Topics

We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)


Nolan Hinshaw
 

On Oct 10, 2020, at 09:41, johnny graybeal <johnnyg@boone.net> wrote:

Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.
What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.


Mike Conder
 

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog=yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal <johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





Mike Conder
 

BTW, great description of the triple valve is here:


Mike Conder

On Sat, Oct 10, 2020 at 11:41 AM Mike Conder <vulturenest1@...> wrote:
Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog=yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal <johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





John Stutz
 

Many thanks for the reference Mike

I was not previously aware of http://www.railway-technical.com/
It is a remarkably informative website.

John Stutz

On October 10, 2020 at 10:45 AM Mike Conder <vulturenest1@...> wrote:

BTW, great description of the triple valve is here:


Mike Conder

On Sat, Oct 10, 2020 at 11:41 AM Mike Conder < vulturenest1@...> wrote:
Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 


Lee Gustafson
 

What happens when an injector is sticking? What do you do?

Lee Gustafson 




On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:


Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog=yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal <johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





John Stutz
 

Mike's reference is a good one, but this one is specific to North American freight brakes:


John Stutz

On October 10, 2020 at 10:45 AM Mike Conder <vulturenest1@...> wrote:

BTW, great description of the triple valve is here:


Mike Conder

On Sat, Oct 10, 2020 at 11:41 AM Mike Conder < vulturenest1@...> wrote:
Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 


John Stutz
 

Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz

On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 


Lee Gustafson
 

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 


On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:


Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 


Climax@...
 

not enough viagra

-----Original Message-----
From: "Lee Gustafson via groups.io"
Sent: Oct 11, 2020 3:46 PM
To: HOn3@groups.io
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 


On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:


Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 


Russ Norris
 

Oh that was soooooo bad.


On Sun, Oct 11, 2020, 4:23 PM <Climax@...> wrote:
not enough viagra

-----Original Message-----
From: "Lee Gustafson via groups.io"
Sent: Oct 11, 2020 3:46 PM
To: HOn3@groups.io
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 


On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:


Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf=aol.com@groups.io> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 


--
Russ Norris, MMR
Cape Cod, Massachusetts
http://blacklogvalleyrailroad.blogspot.com/


John Stutz
 

Lee

I cannot claim much knowledge on the subject, just the basics and a few details.  Injectors came in three basic types: the familiar lifting injector placed high on the boiler, and less known non-lifting injector placed under the cab, which can powered by either full boiler pressure steam or exhaust steam. 

Lifting injectors lift water from the tender or tanks by generating a partial vacuum using a steam jet.  If the water or the injector is too hot, the water will boil and the injector cannot lift it.  Internally the injector is a precise arrangement of concentric converging and diverging cones: A steam jet and venturi for drawing in water and accelerating it, a mixing cone where the steam is condensed, and a pressure cone where the jet's impact builds the pressure needed to force the water into the boiler.  Don't ask me how or why it works - I'm just reporting on what I find in drawings.  But if the feed water contains any suspended grit, or is unusually hard, abrasion or deposition that reshapes the cones will degrade the injector's performance, to possible failure.

With non-lifting injectors, the feed problem is the possibility of drowning the injector with too much water.  They are also subject to the same degradation of the cones.  The exhaust steam version required auxiliary steam from the boiler when the engine was not working, and perhaps on starting, making their construction and operation more complicated than full pressure injectors. These were a fairly late development, say late 1920s, and the only North American narrow gauge use that I am aware of was on the Uintah and NdeM Mallets, and the White Pass 70 & 71.

Probably the most common source of injector failure was operator error, due largely to the multiplicity of designs, each with their unique details and often idiosyncratic operating quirks.

John Stutz

On October 11, 2020 at 12:46 PM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 



On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:

Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 

 


Climax@...
 

John:
This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers?  Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.

Dave

-----Original Message-----
From: John Stutz
Sent: Oct 11, 2020 10:48 PM
To: HOn3@groups.io
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

Lee

I cannot claim much knowledge on the subject, just the basics and a few details.  Injectors came in three basic types: the familiar lifting injector placed high on the boiler, and less known non-lifting injector placed under the cab, which can powered by either full boiler pressure steam or exhaust steam. 

Lifting injectors lift water from the tender or tanks by generating a partial vacuum using a steam jet.  If the water or the injector is too hot, the water will boil and the injector cannot lift it.  Internally the injector is a precise arrangement of concentric converging and diverging cones: A steam jet and venturi for drawing in water and accelerating it, a mixing cone where the steam is condensed, and a pressure cone where the jet's impact builds the pressure needed to force the water into the boiler.  Don't ask me how or why it works - I'm just reporting on what I find in drawings.  But if the feed water contains any suspended grit, or is unusually hard, abrasion or deposition that reshapes the cones will degrade the injector's performance, to possible failure.

With non-lifting injectors, the feed problem is the possibility of drowning the injector with too much water.  They are also subject to the same degradation of the cones.  The exhaust steam version required auxiliary steam from the boiler when the engine was not working, and perhaps on starting, making their construction and operation more complicated than full pressure injectors. These were a fairly late development, say late 1920s, and the only North American narrow gauge use that I am aware of was on the Uintah and NdeM Mallets, and the White Pass 70 & 71.

Probably the most common source of injector failure was operator error, due largely to the multiplicity of designs, each with their unique details and often idiosyncratic operating quirks.

John Stutz
On October 11, 2020 at 12:46 PM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 



On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:

Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 

 


John Stutz
 

Dave

For technical questions, your best source is probably John H White's "American Locomotives", covering early locomotive design and the evolution of design elements up through about 1880-90.  Alfred Bruce's "The Steam Locomotive in America" takes up about where White leaves off, but does not go so far into details.  George Hilton's "American Narrow Gauge Railroads" takes a close look at common carrier narrow gauge power, but Hilton missed the crucial degree to which gauge affected firebox design, and concludes that NG locomotives were basically just downsized SG locomotives.

Early locomotives were fitted with crosshead driven pumps, and this was standard through the 1870s or so.  Some roads did try steam powered pumps of the familiar duplex type, but not many and not for long.  I don't know why this did not work out.  The injector was introduced in the 1860s, enjoyed a brief popularity, was dropped for a decade or so due to reliability issues, then made a comeback; and in its lifting form became the standard into the teens, when non-lifting and later exhaust driven variants made their appearance.  As to why injectors were preferred: clearly the total cost of using injectors was less than that of alternatives, but again I don't know how these costs were balanced.  Pumps were reintroduced for feedwater heater systems, but there the feed was too hot for an injector to handle.  And feedwater heaters were always backed up with an injector.

John Stutz

on October 11, 2020 at 7:59 PM Climax@... wrote:

John:
This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers?  Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.

Dave

-----Original Message-----
From: John Stutz
Sent: Oct 11, 2020 10:48 PM
To: HOn3@groups.io
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

Lee

I cannot claim much knowledge on the subject, just the basics and a few details.  Injectors came in three basic types: the familiar lifting injector placed high on the boiler, and less known non-lifting injector placed under the cab, which can powered by either full boiler pressure steam or exhaust steam. 

Lifting injectors lift water from the tender or tanks by generating a partial vacuum using a steam jet.  If the water or the injector is too hot, the water will boil and the injector cannot lift it.  Internally the injector is a precise arrangement of concentric converging and diverging cones: A steam jet and venturi for drawing in water and accelerating it, a mixing cone where the steam is condensed, and a pressure cone where the jet's impact builds the pressure needed to force the water into the boiler.  Don't ask me how or why it works - I'm just reporting on what I find in drawings.  But if the feed water contains any suspended grit, or is unusually hard, abrasion or deposition that reshapes the cones will degrade the injector's performance, to possible failure.

With non-lifting injectors, the feed problem is the possibility of drowning the injector with too much water.  They are also subject to the same degradation of the cones.  The exhaust steam version required auxiliary steam from the boiler when the engine was not working, and perhaps on starting, making their construction and operation more complicated than full pressure injectors. These were a fairly late development, say late 1920s, and the only North American narrow gauge use that I am aware of was on the Uintah and NdeM Mallets, and the White Pass 70 & 71.

Probably the most common source of injector failure was operator error, due largely to the multiplicity of designs, each with their unique details and often idiosyncratic operating quirks.

John Stutz
On October 11, 2020 at 12:46 PM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 



On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:

Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 

 

 


Mike Conder
 

I think the big thing for injectors over pumps is that the former have no moving parts, virtually no maintenance needed.   Pumps of those days were like small steam engines,  lots of moving parts that needed constant attention and lubrication.   And any failure in it meant the engine would be shut down before the boiler ran out of water. 

As for a sticking injector, I'm guessing that may refer to the valve that opens and closes it?  Not sure if that was manual or steam driven. 

Mike Conder 

On Sun, Oct 11, 2020, 10:36 PM John Stutz <john.stutz@...> wrote:
Dave

For technical questions, your best source is probably John H White's "American Locomotives", covering early locomotive design and the evolution of design elements up through about 1880-90.  Alfred Bruce's "The Steam Locomotive in America" takes up about where White leaves off, but does not go so far into details.  George Hilton's "American Narrow Gauge Railroads" takes a close look at common carrier narrow gauge power, but Hilton missed the crucial degree to which gauge affected firebox design, and concludes that NG locomotives were basically just downsized SG locomotives.

Early locomotives were fitted with crosshead driven pumps, and this was standard through the 1870s or so.  Some roads did try steam powered pumps of the familiar duplex type, but not many and not for long.  I don't know why this did not work out.  The injector was introduced in the 1860s, enjoyed a brief popularity, was dropped for a decade or so due to reliability issues, then made a comeback; and in its lifting form became the standard into the teens, when non-lifting and later exhaust driven variants made their appearance.  As to why injectors were preferred: clearly the total cost of using injectors was less than that of alternatives, but again I don't know how these costs were balanced.  Pumps were reintroduced for feedwater heater systems, but there the feed was too hot for an injector to handle.  And feedwater heaters were always backed up with an injector.

John Stutz

on October 11, 2020 at 7:59 PM Climax@... wrote:

John:
This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers?  Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.

Dave

-----Original Message-----
From: John Stutz
Sent: Oct 11, 2020 10:48 PM
To: HOn3@groups.io
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

Lee

I cannot claim much knowledge on the subject, just the basics and a few details.  Injectors came in three basic types: the familiar lifting injector placed high on the boiler, and less known non-lifting injector placed under the cab, which can powered by either full boiler pressure steam or exhaust steam. 

Lifting injectors lift water from the tender or tanks by generating a partial vacuum using a steam jet.  If the water or the injector is too hot, the water will boil and the injector cannot lift it.  Internally the injector is a precise arrangement of concentric converging and diverging cones: A steam jet and venturi for drawing in water and accelerating it, a mixing cone where the steam is condensed, and a pressure cone where the jet's impact builds the pressure needed to force the water into the boiler.  Don't ask me how or why it works - I'm just reporting on what I find in drawings.  But if the feed water contains any suspended grit, or is unusually hard, abrasion or deposition that reshapes the cones will degrade the injector's performance, to possible failure.

With non-lifting injectors, the feed problem is the possibility of drowning the injector with too much water.  They are also subject to the same degradation of the cones.  The exhaust steam version required auxiliary steam from the boiler when the engine was not working, and perhaps on starting, making their construction and operation more complicated than full pressure injectors. These were a fairly late development, say late 1920s, and the only North American narrow gauge use that I am aware of was on the Uintah and NdeM Mallets, and the White Pass 70 & 71.

Probably the most common source of injector failure was operator error, due largely to the multiplicity of designs, each with their unique details and often idiosyncratic operating quirks.

John Stutz
On October 11, 2020 at 12:46 PM "Lee Gustafson via groups.io" <bagustaf=aol.com@groups.io> wrote:

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 



On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:

Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf=aol.com@groups.io> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 

 

 


Nolan Hinshaw
 

On Oct 11, 2020, at 19:59, Climax@mindspring.com <Climax@Mindspring.com> wrote:

John:
This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers? Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.
Take a good look at early lithographic drawings of locos, especially 4-4-0s, and you may notice a crosshead-driven piston with pipes leading to/from it.


Earl Knoob
 

The great advantage of injectors is that they heat the water being injected into the boiler.  An injector will take water at ambient temperature and by combining the water with the steam, will heat the water up to 180 degrees.  While still less than the 280 degrees or so water boiling at 200psi, it was a big improvement over simply pumping cold water into the boiler.  The cold water, in addition to knocking the steam pressure to hell, produced extra stresses on the boiler.

Some railroads in Central America used crosshead pumps until they gave up steam in the 1960's.


From: HOn3@groups.io <HOn3@groups.io> on behalf of Nolan Hinshaw via groups.io <cearnog@...>
Sent: Monday, October 12, 2020 12:19 PM
To: HOn3@groups.io <HOn3@groups.io>
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)
 
On Oct 11, 2020, at 19:59, Climax@... <Climax@...> wrote:
>
> John:
> This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers?  Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.

Take a good look at early lithographic drawings of locos, especially 4-4-0s, and you may notice a crosshead-driven piston with pipes leading to/from it.







Climax@...
 


Great information and answers a lot of questions Earl.  Thank you .
Dave

-----Original Message-----
From: Earl Knoob
Sent: Oct 12, 2020 5:13 PM
To: "HOn3@groups.io"
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

The great advantage of injectors is that they heat the water being injected into the boiler.  An injector will take water at ambient temperature and by combining the water with the steam, will heat the water up to 180 degrees.  While still less than the 280 degrees or so water boiling at 200psi, it was a big improvement over simply pumping cold water into the boiler.  The cold water, in addition to knocking the steam pressure to hell, produced extra stresses on the boiler.

Some railroads in Central America used crosshead pumps until they gave up steam in the 1960's.


From: HOn3@groups.io <HOn3@groups.io> on behalf of Nolan Hinshaw via groups.io <cearnog@...>
Sent: Monday, October 12, 2020 12:19 PM
To: HOn3@groups.io <HOn3@groups.io>
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)
 
On Oct 11, 2020, at 19:59, Climax@... <Climax@...> wrote:
>
> John:
> This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers?  Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.

Take a good look at early lithographic drawings of locos, especially 4-4-0s, and you may notice a crosshead-driven piston with pipes leading to/from it.







Randy Hees
 

Before injectors, cross head pumps were used.  They were driven off the locomotives piston rods.  The down side was you had to move to put water in the boiler.  Some locomotives had pumps to suck water.  I have used such a pump on a steam tractor to put water in the boiler.  Additionally steam fire engines used thier pumps to put water in the boiler commonly.  I believe that an injector uses less steam.

Randy Hees

On Sun, Oct 11, 2020 at 7:59 PM <Climax@...> wrote:
John:
This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers?  Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.

Dave

-----Original Message-----
From: John Stutz
Sent: Oct 11, 2020 10:48 PM
To: HOn3@groups.io
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

Lee

I cannot claim much knowledge on the subject, just the basics and a few details.  Injectors came in three basic types: the familiar lifting injector placed high on the boiler, and less known non-lifting injector placed under the cab, which can powered by either full boiler pressure steam or exhaust steam. 

Lifting injectors lift water from the tender or tanks by generating a partial vacuum using a steam jet.  If the water or the injector is too hot, the water will boil and the injector cannot lift it.  Internally the injector is a precise arrangement of concentric converging and diverging cones: A steam jet and venturi for drawing in water and accelerating it, a mixing cone where the steam is condensed, and a pressure cone where the jet's impact builds the pressure needed to force the water into the boiler.  Don't ask me how or why it works - I'm just reporting on what I find in drawings.  But if the feed water contains any suspended grit, or is unusually hard, abrasion or deposition that reshapes the cones will degrade the injector's performance, to possible failure.

With non-lifting injectors, the feed problem is the possibility of drowning the injector with too much water.  They are also subject to the same degradation of the cones.  The exhaust steam version required auxiliary steam from the boiler when the engine was not working, and perhaps on starting, making their construction and operation more complicated than full pressure injectors. These were a fairly late development, say late 1920s, and the only North American narrow gauge use that I am aware of was on the Uintah and NdeM Mallets, and the White Pass 70 & 71.

Probably the most common source of injector failure was operator error, due largely to the multiplicity of designs, each with their unique details and often idiosyncratic operating quirks.

John Stutz
On October 11, 2020 at 12:46 PM "Lee Gustafson via groups.io" <bagustaf=aol.com@groups.io> wrote:

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 



On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:

Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf=aol.com@groups.io> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.





 

 


Nolan Hinshaw
 

On Oct 12, 2020, at 14:13, Earl Knoob <earlk489@hotmail.com> wrote:

[...]

The cold water, in addition to knocking the steam pressure to hell, produced extra stresses on the boiler.
One way to mitigate that was to admit the water to the top of the boiler and have a trough running the length with holes in it to allow the water to acquire more heat[0] gradually, and OhByTheWay, a side effect was to precipitate minerals which could form scale or contribute to foaming.

[0] and possibly increase temperature


Kent Hinton
 

Based on personal experience, I’d second John’s notion that operator error may be the most common failure.  An example would be dialing down the feed water flow to allow for a longer sustained injection and reducing the frequency with which you need to inject, then forgetting to open it back up when you close the injector.

From training materials we use at Roots of Motive Power in Willits, CA for the Monitor Edna Type-A screw injector, reasons the injector will not prime include:

- No water in the tank.
- Tank valve is closed.
- Water supply pipe or strainer is clogged.
- Injector water supply valve is closed.
- Air leaks in the suction (water supply) pipe.
- Water in the supply pipe is too hot.
- Overflow valve is closed.
- Defective steam valve or nozzle inside the injector.
- Obstructed boiler check valve.
- Obstructed line (injector exit) check valve.
- Obstructed delivery pipe (nozzle) or the combining and condensing tubes.
- Steam valve to the injector not fully open.
- Insufficient water to condense the steam, due to the water valve or the tank valve not being fully open. (See my example above.)

Nearly half of the above fall under the operator error category.

We’ve also had issues with a Sellers MS injector which our Chief Engineer attributed to a partially fouled delivery check valve which allowed steam from the boiler to back flow into the injector, causing it to overheat and making it difficult to achieve lift.

Kent Hinton


On Oct 11, 2020, at 7:59 PM, "Climax@..." <Climax@... wrote:


John:
This is really going to show my stupidity, but with all this fiddling around with injectors and potential problems why didn't they just use a steam driven pump, kind of like the steam driven generators, to flow water to the boilers?  Like I said I may be missing some huge point, kind of like a blind man in a zoo first feeling an elephants trunk and wondering what it is.

Dave

-----Original Message-----
From: John Stutz
Sent: Oct 11, 2020 10:48 PM
To: HOn3@groups.io
Subject: Re: We be injections (was AIR BRAKES 101.... was Re: RGS #20. Was: [HOn3] Division Point K-27 question)

Lee

I cannot claim much knowledge on the subject, just the basics and a few details.  Injectors came in three basic types: the familiar lifting injector placed high on the boiler, and less known non-lifting injector placed under the cab, which can powered by either full boiler pressure steam or exhaust steam. 

Lifting injectors lift water from the tender or tanks by generating a partial vacuum using a steam jet.  If the water or the injector is too hot, the water will boil and the injector cannot lift it.  Internally the injector is a precise arrangement of concentric converging and diverging cones: A steam jet and venturi for drawing in water and accelerating it, a mixing cone where the steam is condensed, and a pressure cone where the jet's impact builds the pressure needed to force the water into the boiler.  Don't ask me how or why it works - I'm just reporting on what I find in drawings.  But if the feed water contains any suspended grit, or is unusually hard, abrasion or deposition that reshapes the cones will degrade the injector's performance, to possible failure.

With non-lifting injectors, the feed problem is the possibility of drowning the injector with too much water.  They are also subject to the same degradation of the cones.  The exhaust steam version required auxiliary steam from the boiler when the engine was not working, and perhaps on starting, making their construction and operation more complicated than full pressure injectors. These were a fairly late development, say late 1920s, and the only North American narrow gauge use that I am aware of was on the Uintah and NdeM Mallets, and the White Pass 70 & 71.

Probably the most common source of injector failure was operator error, due largely to the multiplicity of designs, each with their unique details and often idiosyncratic operating quirks.

John Stutz
On October 11, 2020 at 12:46 PM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

John,

Thank you for the injector information. A better question is what causes injectors to fail?

Lee Gustafson 



On Oct 11, 2020, at 1:40 PM, John Stutz <john.stutz@...> wrote:

Lee

It is not clear what you are asking.  There are a number of reasons why an injector can fail to inject water into the boiler, most of which I have forgotten.  But I cannot recall any that I would describe as "stuck". 

None have anything to do with air brakes.

If an injector fails, you can hope to finish your run on the other one.  If both fail, you can try to make it into a siding with the water already in the boiler, but you had damm well better drop the fire before the crownsheet is uncovered.

John Stutz
On October 10, 2020 at 11:32 AM "Lee Gustafson via groups.io" <bagustaf@...> wrote:

What happens when an injector is sticking? What do you do?

Lee Gustafson 





On Oct 10, 2020, at 12:41 PM, Mike Conder <vulturenest1@...> wrote:

Sort of, I think.  The injector uses internal venturis powered by steam.  The venturis create a high velocity and low pressure (via conservation of energy) and then the mix is going fast enough and is now dense enough to get into the boiler.  Seems like magic, but it's just brilliant mechanical engineering! (and the triple valve is ALSO brilliant mechanical engineering!)

Mike Conder, mechanical engineer

On Sat, Oct 10, 2020 at 10:54 AM Nolan Hinshaw via groups.io <cearnog= yahoo.com@groups.io> wrote:
On Oct 10, 2020, at 09:41, johnny graybeal < johnnyg@...> wrote:

> Reading the old books on this can be very confusing, but less so than talking about how a check valve lets water of less pressure go into a boiler of higher pressure. That still gives me headaches.

What forces water from an injector through a check valve is impulse, not pressure, It's the energy water (density higher than steam's) gets passing through an injector and gaining velocity (momentum is mass times the square of velocity, wherefrom impulse, which depends on compressing that momentum into very small intervals of time,...). Simple Newtonian mechanics at work - nothing to see here - move along...

From a pump, there's the force multiplier between the steam cylinder(s) and the water cylinder(s) that produces a positive pressure differential at the check.