Tuesday, January 5, 2010

Mono Block Valve

hydo said...
Sorry but i forgot how to post a new question and just jumped in this .
iam having a problem with gear pump witch is connected via a monoblock to a pressure guage.
problem is that when i switch the dcv 'on' the guage showes 190 bar ,but for just for one second
then it start to go doun to 100 bar and stay at 100 bar.

as i switch off and then on again
it goes to 150 and then goes down again.
is it relief walve which is releasing pressure and not settlig down again till pressure goes down to 100 bar , if it is pressure should rise again .can a pilot oprated relief solve this .
forgive me for a so basic and not mind frying question.

January 5, 2010 3:51 AM


JDK said...

Thank you for the question.

A direct operated relief is typically faster acting than a pilot relief - usually less than 100 msec. If you are seeing this on a gage, maybe your relief is dirty and therefore lagging. Maybe your monoblock is shifting slowly and temporarily blocking fluid. If you are clearly seeing this spike on a gage I would start with a problematic relief.

Buddha said...

what abt case drain leakage?

have u ruled that out..?

JDK said...

Please explain??

punter said...

Thanks JDK

but thats what i did after posting last question.
fully tighten the monoblock relief
Not worked.

then i put another line mounted relief diractly on the outlet of the pump resulet was the same
Everything workes right until pressure goes to 175bar,then starts to go down untill 50 or 70 bar and stays there.

then i tried the pilot relief but in vane.

is the pump worn out ?

there is no positive responce even if i increase the input rpm on the pump.

the pump is heating up .

one more thing it workes well when the relief sat at 120 bar, 130 bar,or even 150.

JDK said...

What is your relief valve setting?

hydo said...

frist i started with relief fully open.
started the pump then slowly turned the setting screw and the guage showed 100 bar and stayed still , it mean pressure is 100 bar and relief is opening at 100 bar ,

then i truned it more after showing 175 bar the guage reading goes down ,even if i set the relief at full pressure 315 bar.

JDK said...

"then i truned it more after showing 175 bar the guage reading goes down ,even if i set the relief at full pressure 315 bar."

1. Goes down to what?
2. How are you blocking the fluid flow to set the relief?

hydo said...

the third port on thr relief is blocked .fluid is going no where , the only way out is the relief valve.

any how i am installing a new pump tommarow.

hydo said...

new pump is working fine, it was a pump problem.

can any one tell ,wahat is the pump "maximum working pressure rating" is.

if the manufacturer says 210 bar .
it means 0 pressure on suction port and 210 bar on outlet.

can i give 50 bar on suction port and make the pump work at 260 bar without redusing the pump lifetime.
the pump is not going to explode at 260 i am sure.

JDK said...

Maximum Suction and Outlet port pressures are specified by the pump manufacturer and are usually not related.