looking for Automatic Airvent (Help and advise )

[bmw318be]

am looking for an Automatic Air Vent Valve to be used with Gear Pumps to clear an air lock while the pump is priming. Please advise if you have a suitable product?

Operating Pressure - Max 10 Barg
SG - 0.92
Viscosity - 30000 cp
Pumping Temperature - 100 deg C (Maximum)

 

[pennpiper]

You could try here:

http://www.watts.com/pages/_products_details.asp?pid=664

or

http://www.spiraxsarco.com/pdfs/sb/s31_06.pdf

or

https://www.google.com/search?q=aut...lMYL09gTB2YHADA&ved=0CE8QsAQ&biw=1024&bih=665

the last one is real good

prognosis: Lead or Lag

 

[bmw318be]

Google yes is the best, however it sometimes recommended user would be best !

 

[bimr]

Why don't you use a manual valve? What fluid are you pumping?

 

[Oldhydroman]

Would a Hydac AEV6 be any good?

Not sure about the 100 deg C operation but you could always ask.

DOL

 

[bmw318be]

THe liquid is polymers

 

[bmw318be]

The liquid is very viscous, Polymer sols which has viscosity about 30,000. I am having a problem, the pump does not get the capacity. Would the issue is caused by airlock ? . Would any Airvent valve is suitable for polymer which has very high viscous.

 

[Pumpsonly]

If you just want to vent the piping, just a manual valve at the high point of the pipoing will do. The gear pump does not air locked . Check the suction pressure. Is it sufficient for the pump NPIPR ? For such high viscosity liquid you will need a lot of pressure.

 

[bmw318be]

Hi pumponly, are u referring to NPSHr is sufficient or not ? . Pump has no noise and the discharge shows 3.5 bars and seems it has sufficient pressure, however the real problem seems the airlock when the pump is designed to pump high viscous liquid.


Can u elaborate how you install the airvent manual, i m not too sure the application of auto vs manual

 

[Compositepro]

What is feeding you gear pump? Gear pumps are generally not self priming. Sounds like you need a screw extruder with a vented barrel. Gear pumps are used on screw extruders for price flow control. If you are relying on gravity feed to the pump, for 30,000 cP, the inlet piping must be large diameter and short in length, and cavitation at the inlet to the pump is quite possible. An air vent will not help.

 

[bimr]

Agree with Compositepro. An air vent is not practical on the liquid that you are describing.

 

[bmw318be]

Hi compositepro, my gearpump
Is actually need NPSHr 1.5
M. I think you are right there is cavitation as the sucking tank is probably not in high elevation. My q is

shoould i increase the elevation of the tank so there is enough NPSHa

What is the purpose for the screw extruder,will it bring down the viscosity ?


When we could use aivent ?

 

[Pumpsonly]

You did not provide info on the pump capacity, RPM , inlet size etc.
The NPSHr 0f 1.5 M for the pump is based on pumping what liquid / viscosity?
The NPSHr will increase with the liquid viscosity even at same flow rate.

With liquid of 30,000cP , you will not hear any noise even if the pump is cavitating.

I don't think the polymer at 100C you mentioned is the same type of polymer Compositepro,is referring to.
The gear pump /extruder combination mentioned in his post is for the plastic industries typically by MAAG pump which act as a booster for the extruder.

 

[bmw318be]

The pump should be able to pump 30 m3 per hr, however it take 200 l / per hr .

The NPSHr 1.5 is for 30,000 cps . It designed
At this rated flow. However the issue is the flow . Anyway i could check the cavitation occurs ?


How to improve the flows

 

[bmw318be]

Does anyone know air vent that could be set at lower differential pressure of 0.5 bar,I am having a supplier hydac which they can provide airvent with diff P 3 bar.
Differential Pmin is too high at 3 bar. I need to close valve  at dp minimum of 0.5 bar, Because the pump currently experiences a differential pressure of approximately 2 bar. So this valve will not close if it requires dp min of 3 bar.

Here is the airvent they offer

https://www.dropbox.com/s/7egea3mga8w5luy/Hydacusa.pdf

 

[bimr]

Why don't your post a P & ID of your system?

 

[bmw318be]

What is P & ID ?

 

[Pumpsonly]

Piping and Instrumentation Diagram.

 

[bmw318be]

Sorry, do not have the configuration:

It basicly sucking from a closed tank and there is a heat exchanger that solidify the polymer solution . Probably there is cavitation on the suction as mentioned by forumer. Would that be possible to have auto vent airvent valve

 

[MikeHalloran]

Did the shaft get bent when the polymer kicked?

Did this system _ever_ work?



Mike Halloran
Pembroke Pines, FL, USA