300 psi TSC pump surging when using small drills.

ChipSplitter

Titanium

Joined

May 23, 2019

Location

Maybe

• Jun 2, 2020

• #1

I noticed it today when we were using a 5.9 mm drill.
Tool is an OSG Mega Muscle with really small coolant holes, probably .02-.03" dia.
It surges up and down and the coolant flow is changing constantly.
The pump does fine with other tools that have larger coolant holes.

Anything to do about it? Or is it just normal?

 

D

D.D.Machine

Stainless

Joined

Dec 10, 2003

Location

poulsbo, wa, usa

• Jun 3, 2020

• #2

I have a feeling your pump is cavitating do to the little amount of flow its seeing ,,, you might try a dump valve so you can increase the flow going throe the pump ,,, I have had lathe pumps do that when there is only one small jet to flow coolant … I just put in a dump valve and would dump some coolant from the pump back into the sump to fix it ..

 

J

johansen

Stainless

Joined

Aug 16, 2014

Location

silverdale wa

• Jun 3, 2020

• #3

cavitation is also influenced by the gas pulled out of the fluid on the suction side of the pump. if the gas does not get pushed downstream it flows around the impeller through the seals. or lack of seals, and the pumping action nearly stops.

check inlet filter restrictions.

 

ChipSplitter

Titanium

Joined

May 23, 2019

Location

Maybe

• Jun 3, 2020

• #4

I was wondering about that, because it sounded like it was cavitating a bit.
So it's more or less bypassing internally?

 

Mike1974

Diamond

Joined

Nov 5, 2014

Location

Tampa area

• Jun 3, 2020

• #5

I don't know this for fact, but I was taught that 300psi isn't enough for smaller tools... don't know the reasoning behind that?

 

M

Mark Rand

Diamond

Joined

Jul 9, 2007

Location

UK Rugby Warwickshire

• Jun 3, 2020

• #6

If it's a centrifugal pump, it is either stalling with the low flow or the coolant is recirculating in the pump. A dump valve will help cure either case. Cavitation in a centrifugal pump occurs when the inlet is restricted and the net positive suction head gets below the vapour pressure of the fluid.

 

ChipSplitter

Titanium

Joined

May 23, 2019

Location

Maybe

• Jun 3, 2020

• #7

Would the dump valve be activated via an M-code?
And how would you control the flow being relieved, IOW so it doesn't all go through the dump valve?

 

ChipSplitter

Titanium

Joined

May 23, 2019

Location

Maybe

• Jun 3, 2020

• #8

Mike1974 said:

I don't know this for fact, but I was taught that 300psi isn't enough for smaller tools... don't know the reasoning behind that?

Click to expand...

Theory is that you need more pressure to force coolant through the small holes.
All too true......

 

S

SIM

Titanium

Joined

Feb 19, 2004

Location

Staten Island NewYork USA

• Jun 3, 2020

• #9

T the line it with a manually adjustable valve. Turn coolant on and open valve till your pumps working correctly and run it that way for all your tools. When done with job, shut the valve. OR buy an electric valve to go more elaborate that opens and shuts the T- feed to the manual...you still need to control the flow.

 

ChipSplitter

Titanium

Joined

May 23, 2019

Location

Maybe

• Jun 3, 2020

• #10

SIM said:

T the line it with a manually adjustable valve. Turn coolant on and open valve till your pumps working correctly and run it that way for all your tools. When done with job, shut the valve. OR buy an electric valve to go more elaborate that opens and shuts the T- feed to the manual...you still need to control the flow.

Click to expand...

I could probably put a solenoid valve and a flow control together and control it that way.....

 

mhajicek

Diamond

Joined

May 11, 2017

Location

Maple Grove, MN, USA

• Jun 3, 2020

• #11

I believe there's an overpressure relief valve, that could be toggling. I have 1000PSI TSC, and when a small drill is in the work I'll hear a rhythmic thumping sound as it oscillates. Don't hear it if there's reasonable flow or if it's fully blocked with a non-TSC holder.

 

ChipSplitter

Titanium

Joined

May 23, 2019

Location

Maybe

• Jun 6, 2020

• #12

mhajicek said:

I believe there's an overpressure relief valve, that could be toggling. I have 1000PSI TSC, and when a small drill is in the work I'll hear a rhythmic thumping sound as it oscillates. Don't hear it if there's reasonable flow or if it's fully blocked with a non-TSC holder.

Click to expand...

Yes, that's what it sounds like. I'll put a dump valve in the next time we use that tool (2-6 weeks) and let you guys know if it worked.

 

ChipSplitter

Titanium

Joined

May 23, 2019

Location

Maybe

• Jun 9, 2020

• #13

Update:

We had a job this morning that used that same drill so I teed in a needle valve. The pump now sounds a lot better and doesn't cavitate.

Thanks for all your help guys.