Author Topic: Stuart Boiler Feed Pump  (Read 43660 times)

Online Maryak

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Re: Stuart Boiler Feed Pump
« Reply #45 on: November 18, 2013, 12:43:24 PM »
Hi Florian,

Your diagram looks like a variation on the Weirs Glissard Valve. If bypass ports are fitted the steam can be supplied for the whole length of the stroke to either end by rotating the auxilairy valve which, whilst not 100% fool proof, usually manages to get the pump restarted should it stop on the top or bottom of the stroke, where the main valve has closed off all the ports.

Solution 2 is a bloody big crowbar and a large block of wood under/over the X head.  :hammerbash:

Food for thought maybe?

Best Regards
Bob
Если вы у Тетушки были яйца, она была бы Дядюшкой

Offline Florian Eberhard

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Re: Stuart Boiler Feed Pump
« Reply #46 on: November 18, 2013, 12:53:02 PM »
Hi Bob

I will see how it runs and modify it if it doesnt run nice.
It wouldn't be so bad for me if I had to move it to the right position before starting (auxiliary valve or piston)

But as I said, I will first let it run and see what happens.

Offline Captain Jerry

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Re: Stuart Boiler Feed Pump
« Reply #47 on: November 18, 2013, 04:30:01 PM »
Florian

I'm with you on this one.  Your modification does not change the way that the valve works. It only replaces two piston valves with two slide valves and I think your reasoning for that is valid and also interesting.  Your doubters seem to forget that steam is supplied to the piston by the shuttle valve, which is not directly linked to the eccentric but is more of and either/or device controlled by the primary valve and as you state, is highly unlikely to come to rest between states.   If you have any problems getting regular cycling, i would bet that fine tuning the primary valve will resolve them.

Jerry
There are thing that you can do and some things you can't do.
Don't worry about it. try it anyway.

Offline steamer

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Re: Stuart Boiler Feed Pump
« Reply #48 on: November 18, 2013, 04:38:53 PM »
No nay sayers Jerry....just a polite discussion of the attributes involved.    :ThumbsUp:

The way is should be.



Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline K.B.C

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Re: Stuart Boiler Feed Pump
« Reply #49 on: November 18, 2013, 05:22:40 PM »
Oh, George, when im already having such an old hand with those Pumps reading my thread:

How do you fix the water pump body to the cast iron base? The Stuart plans just "forget" about and I haven't seen any hints on how it was intended.
Am I just blind...?

Also on the internet, i wasn't able to find any hints.

Florian,
I make the water pump casting a hard push fit by hand into the casting and leave it as such until the pump with the piston is complete and with your machinenery and skills you probably will not need to do the following.

You mentioned earlier that one of the main things to get this pump to work was that the 1/4" dia ram had to be  directly in line with the piston in the cylinder and I will confirm that this is so.

I have been given many pumps that wouldn't work because of this so what I do is  make the water pump gun metal casting a loose fit in the main frame .002" - .003" undersize I machine annular groves with a parting tool on the dia, (3-off,) push the piston fully towards the water pump end, coat the undersize water pump grooves with Loctite 603 and push it on to the cast frame, stand it vertical over night and I have never had any further trouble.

A bit unconventional but effective,if you don't need to do as described if you can push the pump ram back and forward by hand when you have the auxiliary bracket fixed to the shaft  I would still run an annular groove on the pump casting and fix with Loctite, after all once on there is no need for it to come back off.

George.
P.S.
I also always fit a Silicone  "O" ring to the 1/2" dia piston
Your never too old to learn.

Offline K.B.C

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Re: Stuart Boiler Feed Pump
« Reply #50 on: November 18, 2013, 08:47:04 PM »
No nay sayers Jerry....just a polite discussion of the attributes involved.    :ThumbsUp:

The way is should be.



Dave

Thank you Dave.

George.
Your never too old to learn.

Offline steamer

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Re: Stuart Boiler Feed Pump
« Reply #51 on: November 18, 2013, 09:24:39 PM »
Thank you George!

Ya know....it ain't easy.    We as a team try to keep is cool and civil.  We all don't have to agree....as a matter of fact disagreement is encouraged to a certain extent....but doing so politely...and most importantly...respectfully is the key.   

If as a group we figure that one out....we're golden...and from what I've seen we're doing just fine!

So keep it talking guys....and gals....keep talking.


Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline K.B.C

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Re: Stuart Boiler Feed Pump
« Reply #52 on: November 18, 2013, 09:31:44 PM »
I have great reservations that your pump will not work.

Hi George

Well, there could theoretically be a case where all the ports are closed. But the probability is very small because the auxiliary valve will have to get over the point where the ports are equally closed until the shuttle valve is going to move.

To describe it with an analogy: It is like having a pendulum stopping with the mass above the bearing point.
It is possible because of friction but the probability is very small and the stability at this state is very low.

Here is a scheme for the principle of my pump:


If you look at it carefully you will find out that it wouldn't work that way, the piston would drive the auxiliary valve to the wrong direction.
But I have drawn the ports this way to make it clearer when looking at it.

If it should happen, that I am really gonna have problems, I will see what I can do.

Greetings Florian


Florin,
May I go back to your post with the C.A.D.  and ask the question.
If the auxiliary valve is operated by the pump rod this means that they are both going in the same direction, as the original Stuart pump.

In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?

George.
Pic of the Stuart pump with the auxiliary valve driven by the pump ram.


Florian,
May I go back to your post with the C.A.D.  and ask the question.
If the auxiliary valve is operated by the pump rod this means that they are both going in the same direction, as the original Stuart pump.

In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?

George.
Pic of the Stuart pump with the auxiliary valve driven by the pump ram.

Your never too old to learn.

Offline K.B.C

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Re: Stuart Boiler Feed Pump
« Reply #53 on: November 18, 2013, 09:40:09 PM »
Florian

I'm with you on this one.  Your modification does not change the way that the valve works. It only replaces two piston valves with two slide valves and I think your reasoning for that is valid and also interesting.  Your doubters seem to forget that steam is supplied to the piston by the shuttle valve, which is not directly linked to the eccentric but is more of and either/or device controlled by the primary valve and as you state, is highly unlikely to come to rest between states.   If you have any problems getting regular cycling, i would bet that fine tuning the primary valve will resolve them.

Jerry

Jerry
If you look at the pic Florian posted and the pic that I have posted you will see that no eccentrics are used.
The auxiliary valve is driven in the same direction as the pump ram.
Also there will be no way to fine tune the valves as Florian is cutting a steam space on the underside of the top steam chest with no way of access to see what is happening, not like a valve chest that has a bolt on cover, so I still have my doubts but willing to be shown how it can be done, never too old to learn.

George.
Your never too old to learn.

Offline Captain Jerry

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Re: Stuart Boiler Feed Pump
« Reply #54 on: November 18, 2013, 09:54:45 PM »
My apologies to anyone that I offended with my remarks.  I am a little confused as to what was offensive as it was not intended to be.  Several of my recent post seem to have caused ill feelings so it must have something to do with my general attitude which, I must admit, has not been good lately.  I will refrain from posting until I have a better outlook.

Jerry
There are thing that you can do and some things you can't do.
Don't worry about it. try it anyway.

Offline steamer

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Re: Stuart Boiler Feed Pump
« Reply #55 on: November 18, 2013, 10:49:53 PM »
I saw nor construed nothing offensive Jerry....Deep breath everybody....hmmm.

Dave
 
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Florian Eberhard

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Re: Stuart Boiler Feed Pump
« Reply #56 on: November 19, 2013, 12:08:35 AM »

In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?


As I said, the drawing (made with paint) is not correct.
I only made it for showing ports and valve arrangment.
The auxiliary valve would of course have to be on the other side so the piston ram could move it to where it already is in my drawing.
This would then cause the shuttle valve to switch position as well and the piston would go into the wrong direction.

BUT:
On my Pump, the ports between the auxiliary valve and the shuttle piston are crossed. And that would then make everything right.

As you see, my drawing can not be drawn correctly but I did chose to draw it that way because crossed ports in that drawing might confuse someone.

Cheers Florian

Offline steamer

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Re: Stuart Boiler Feed Pump
« Reply #57 on: November 19, 2013, 12:25:58 AM »
That seems understandable and reasonable Florian.   Please proceed. 8)

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline Don1966

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Re: Stuart Boiler Feed Pump
« Reply #58 on: November 19, 2013, 12:39:05 AM »
I am intrigued by this discussion, you both have some very good points and I will stay tuned in the see how it all works out. I can see both sides of this and can't make up my mind who is correct. Florian you are showing so great engineering skills.
George your pump is gorgeous and thanks for starting the discussion.

Regards Don

Offline K.B.C

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Re: Stuart Boiler Feed Pump
« Reply #59 on: November 19, 2013, 11:30:39 AM »

In your drawing it shows the piston in mid stroke and the Shuttle valve covering both ports, is this a small mistake, if not how does the steam get into the L/H. side to blow the piston to the bottom and as the shuttle is hard against the R/H side how are you to move it to get steam behind the piston to blow it to the top. ?


As I said, the drawing (made with paint) is not correct.
I only made it for showing ports and valve arrangment.
The auxiliary valve would of course have to be on the other side so the piston ram could move it to where it already is in my drawing.
This would then cause the shuttle valve to switch position as well and the piston would go into the wrong direction.

BUT:
On my Pump, the ports between the auxiliary valve and the shuttle piston are crossed. And that would then make everything right.

As you see, my drawing can not be drawn correctly but I did chose to draw it that way because crossed ports in that drawing might confuse someone.

Cheers Florian

Florian,

Gotcha !!
Yes you will need to transfer the ports to get the shuttle to work.

I have made a small 3" high vertical WEIR type pump from stock material and  from the drawings by Southworth pumps and there is a plate between the steam chest and the cylinder face which has the steam ports transferred to get the shuttle to work, I hope that it's visible on the enclosed pic.
This little pump is very reliable and works down to about 5 p.s.i and is self starting every time, pics enclosed and I hope you can see the groove to transfer the steam.

I have also made a vertical WEIR type pump 6" high from a set of castings and it transfers the steam by various galleries to get the steam transferred, both of these pumps are slide valve operated.

I didn't quite understand your C.A.D. drawing but thanks for explaining, technology has passed me by I am afraid to say and I still rely on sketches on a pad, unfortunately I didn't take any pics of the slide valve arrangement but I could scan and post them to you by e-mail if you wish, just P.M. me with your mail address.

Keep up the good work and I look forward to seeing you complete the project.

George.

This is the 6" high pump.

 
« Last Edit: November 19, 2013, 04:08:36 PM by K.B.C »
Your never too old to learn.