Why Pumps have Vent and drain?

(1) ethanhan Vent and drain 20 March 2008, 05:41 PM

(2) pumps100 (John) Dear Ethanhan, I think you... 20th March 2008, 06:31 PM

(3) S. L. Abhyankar Vent and Drain are also... 21st March 2008, 04:50 PM

(1) To all experts

Why vent and drain are needed in pump??? probably where is it located?

Thanks(especially John)

Hor Win Han (Ethanan)

(2)

Dear Ethanhan,

I think you are referring to vent and drain connections pursuant to API 610 sealing plans. Can I ask that for future queries if the query relates to API pumps please say so.

I will assume that your query relates to API610. I must confess that I don’t have that much experience in relation to centrifugal pumps used in the petroleum, petrochemical and natural gas industry; but I will try my best to answer your query.

Within API 610 there are a number of shaft sealing plans which I believe cross relate to API 682 Shaft sealing systems for centrifugal and rotary pumps. See also ISO 21049.

The standards will provide for a number of tappings (normally half inch NPT I think?) in the seal chamber on the API 610 pumps. These tappings may be used, or not used, dependent on the pumping application. These are normally located in the seal chamber.

The vent and drain connection – sometimes also called the quench connection can be used for a number of purposes. For example suppose you were pumping some really thick stuff like bitumen or tar you could introduce low pressure steam to stop the ‘liquid’ solidifying on the shaft/mech seal when the pump was stopped or when the liquid cooled down to ambient temperature.

You could also use the tapping to use a water flush to take away any leakage from the seal area. In the event of a seal failure (if a double mech seal was used) the ‘vent’ could take away this liquid – this is handy for example if you were pumping something nasty like acid or other highly corrosive or toxic liquids.

But please look at API 610 and API 682 for further guidance as I am no expert in this field.

Regards

John

(3)

Dear Mr. Hor Win Han,

Vent and Drain are also provided on most volute casings of centrifugal pumps.

The vent connection is to release any air or gases likely to get entrapped in the casing, which is always a possibility especially with split casing pumps and end-suction pumps with side discharge volute.

Drain connection is of course at the bottom-most portion to drain, better still, flush and drain any settle-able foreign matter entraining in the flow or material disintegrating due to corrosion or abrasion.

The drain connection will be of fairly large size in case of solids-handling pumps, such as paper stock pumps.

Hygienic pumps, such as pumps in dairies need flushing at regular intervals. So, instead of a simple drain connection, the pumps are provided with quick clamping and unclamping feature.

Hope, this clarifies your query.

S. L. Abhyankar