Water pump locked up??

This topic has 9 replies, 5 voices, and was last updated 28 January 2013 at 20:12 by MICHAEL WILLIAMS.

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25 January 2013 at 20:55 #110057
nigel jones 5
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@nigeljones5
The water pump on my 5" just locked solid and bent the 3/8 stainless ram like a banana! Total strip down required to remove it. I cant see how it can have hydraulicd but theres no sign of abrasion on it. Boiler was at 80+psi when I opened the regulator. Any ideas? (eccentric driven)
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25 January 2013 at 20:55 #6541
nigel jones 5
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@nigeljones5
25 January 2013 at 21:15 #110060
Nigel Hyde
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@nigelhyde97004
Hi

i had the same problem on my tich 2 weeks ago, but on the hand pump

i had fitted nitrile (?) balls and they had squashed themselfs and stopped me from getting water in the bolier, not ideal!

put stainless ones in and no problem

hope this helps

Nigel
27 January 2013 at 01:03 #110166
nigel jones 5
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@nigeljones5
ping ping ping !!
27 January 2013 at 10:06 #110184
Mark P.
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@markp
By pass valve blocked?

Mark P.
27 January 2013 at 12:20 #110199
MICHAEL WILLIAMS
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@michaelwilliams41215
Hi Fizzy ,

There is one thing to look for which is a common cause of bent pistons and rods in full size pumps but which is not too obvious .

Its just down to the geometry of piston , cylinder and connecting rod .

If engagement of piston is too short in cylinder and / or connecting rod comes in at too steep an angle mechanical lock can occur – basically the piston and connecting rod do a hinged buckle and piston is forced hard sideways or up / down ( depending on the set up ) against inside of cylinder .

Michael Williams .

PS: I believe that you mentioned that you were a diver . There is alot of interesting engineering in diving equipment – want to tell us about some of it ?
27 January 2013 at 13:00 #110208
nigel jones 5
Participant
@nigeljones5
Thanks Michael

It sounds like a geometry problem for sure, thing is I dont know how to put it right – any suggestions on do's and dont's? I waas always weary of it as I had to fasten the con rod to the top of the strap (as opposed to the middle) so that it wouls line up with the pump. This worked fine whilst running on air but bent when at steam pressure. Diving equipment – never thought of it as interesting….ust bloody expensive! Its all O ring technology, if an O ring fails you die, so we never ever modified equipment
27 January 2013 at 21:36 #110250
John Hyde 1
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@johnhyde1
Does appear you have given yourself the answer to the fault! Running on air, pumping nothing was easy,water at 80 psi?……..surprised the strap didn't smash as well! I would guess the pumps therefore in the wrong position, requiring lowering. First thing to do is check out what you've got against the drawings for that loco.

(The suggestion of jamming nitrile balls was given earlier on the basis that all else was correct and that the loco had previously been running under steam with no fault.. We have had jamming clacks on two loco's,caused I believe by nitrile balls jamming in the clacks when at working pressure.One result was a smashed hand pump lever! Conversion back to Stainless balls solved the problem.)
28 January 2013 at 18:35 #110337
nigel jones 5
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@nigeljones5
Drawings…..there are no drawings! Apart from designing the joy valve gear its all been pen, paper and imagination!I neglected to count the angle/position of the pump body in relation to the eccentric when building it. Im loathed to strip it all out again as it runs so sweet. Another look, take some measurements and draw it in cad, see what can be done. Thanks.
28 January 2013 at 20:12 #110347
MICHAEL WILLIAMS
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@michaelwilliams41215
Hi Fizzy ,

Pictures would probably do .

Regards ,

Michael Williams
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