Diaphragm Dosing Pump

• Nov 12, 2022

• #2

TugboatEng

Marine/Ocean

Nov 1, 2015

11,839

Diaphragm pumps will free-flow in the direction of flow when stopped. If your dosing tank level is above the pump you may experience this. Consider moving the pump above the dosing tank.

 

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• Nov 12, 2022

• Thread starter
• #3

Elons_Nephew

Electrical

Nov 12, 2022

3

Thank you very much.

 

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• Nov 13, 2022

• #4

LittleInch

Petroleum

Mar 27, 2013

22,602

Agree.

If there is a positive pressure difference between inlet and outlet then flow will continue. The check valves stop the flow going backwards

Also include an actuated valve.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

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• Nov 13, 2022

• Thread starter
• #5

Elons_Nephew

Electrical

Nov 12, 2022

3

Please see above, as I did respond to the first reply with a thank you.
And I thank you as well for your knowledge on this situation.
The chemical pump is slightly below the tank, and the outlet is submerged in a tank of moving water. There once was an actuated valve on the outlet but at some point someone decided it was not required and removed it.

 

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• Nov 13, 2022

• #6

MortenA

Chemical

Aug 20, 2001

2,998

@Elons, so it sound to me that you source is higher than your destination - then the "pump" will free flow - that is it will stop at once but flow will continue at a lower rate. If your desitation has a higher pressure than your source this may not be the case but thats not clear from the describtion "tank of moving water".

Best regards, Morten

--- Best regards, Morten Andersen

 

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• Nov 14, 2022

• #7

LittleInch

Petroleum

Mar 27, 2013

22,602

Elons Nephew said:

There once was an actuated valve on the outlet but at some point someone decided it was not required and removed it.

Click to expand...

Well try and find that person and then make sure you don't listen to them anymore.....

So just replace it.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

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• Nov 14, 2022

• #8

pierreick

Chemical

Nov 20, 2005

1,472

Hi,
Make sure your "new actuated valve " will be open at the start of the pump with proper interlocks! Safety concern.
Safety review needed.
Pierre

 

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• Nov 18, 2022

• #9

bimr

Civil/Environmental

Feb 25, 2003

9,369

This particular pump is not supposed to siphon:

"Back Pressure / Anti-Siphon Valve
1. A spring-loaded diaphragm under the back pressure knob automatically adds approximately 36PSI (15 PSI
for low pressure versions) of back pressure to the discharge side of the pump when the knob is set to the
“BV” position.
2. The diaphragm also prevents siphoning of chemical through the pump."

If all else fails, read the instruction manual:

Pump Manual

 

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• Nov 18, 2022

• #10

LittleInch

Petroleum

Mar 27, 2013

22,602

That only seems to apply IF it's fitted.

Section 2.5 specifically says it's not an anti syphon valve for the main injection valve.

Section 3.7 where your data comes from is optional and also it needs to be set to BV.

We don't know what is fitted or what position this mysterious multi purpose valve is set at if its fitted.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

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