Water pump locked up??

[nigel jones 5Participant @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)

[nigel jones 5Participant @nigeljones5]

[Nigel HydeParticipant @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

[nigel jones 5Participant @nigeljones5]

ping ping ping !!

[Mark P.Participant @markp]

By pass valve blocked?

Mark P.

[MICHAEL WILLIAMSParticipant @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 ?

[nigel jones 5Participant @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

[John Hyde 1Participant @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.)

[nigel jones 5Participant @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.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi Fizzy ,

Pictures would probably do .

Regards ,

Michael Williams

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