Diaphragm Dosing Pump

[Elons_Nephew]

Hello,

I have a IWAKI EZ B16D1-VCA diaphragm dosing pump. I have a colleague who is adamant that when this pump is running full speed, 360Hz that if you shut it off fluid keeps flowing and the pump continues to pump. With my experience with a diaphragm dosing pump, as soon as the power is removed from the coil the diaphragm stops moving and the check valves stop the flow.
Has anyone had any experience with these pumps acting like this? I have tried reproducing this condition to no avail.

 

[TugboatEng]

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.

 

[Elons_Nephew]

Thank you very much.

 

[LittleInch]

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.

 

[Elons_Nephew]

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.

 

[MortenA]

@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

 

[LittleInch]

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

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.

 

[pierreick]

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

 

[bimr]

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

 

[LittleInch]

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.