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I understand for temp >180F we should be using a cooler to seal..what if the pressure is high enough to exceed the vapour pressure of water considersably..is taht OK or should we still be cooling? Somebody told me that the lubricity characteristic of water goes down, hence exceeding the vapour...

One more question on this topic..say we have bubbles inside the seal chamber prior to starting up the pump but it is flooded..what issues will arise in the pump if the bubbles are recirculated back to suction? Do those implode after passing back through the impeller eye and damage impeller...

Thanks very much for the info! Appreciate all the help!

To add to that last question JJPellin, the example you had worked out was determining the target seal chamber first..30psid between the VP and Seal Chamber..but what if we need to have full discharge in the seal chamber to maximize the VP margin..can we still go with a 14? If so, how would this...

JJPellin, The last comment in the thread you referencing is the following: "If the pump is a verticasl turbine style model, than a plan 13 is really all you need. A plan 11 in that situation would provide zero flow as the respective pressures (discharge and seal chamber) would be equal." That...

Thanks folks..so if I would like to increase the heat transfer of the process fluid through the tubes, I should increase the flow rate to ensure it is turbulent flow..this way the exit temp will lower as opposed to slowing the flow rate down which creates a laminar flow which depends on the...

Hi All, Quick question..vertical pump does not have back wear rings and balance holes due to high suction pressure..we need full discharge pressure in the seal chamber to maintain the API (30%) vapour pressure margin..I am suggesting API Plan 13 to right choice, however, would you open up the...

Thanks for the response folks. The vapour pressure was 114psia which I then converted to gauge. One more question for you folks..I was told by a pump vendor that even though the suction pressure is very close to the vapour pressure, there is nothing to worry about as there is sufficient...

Hello, could you someone explain to me the effect of increasing the process fluid flow rate, in the tube, in regards to the heat transfer to the cooling water in the shell? What happens if I increase or decrease the flow rate in the tube by keeping the cooling water flow rate constant? What...

Hopefully somebody could correct me here as I must be doing something wrong. The suction pressure on this vertical pump is 106psig and the vapour pressure is 100psig. The suction pressure was taken off of the centrifugal pump datasheet. Subtracting the vapour pressure from the suction...

Seal vendor has asked for the tubing to be 3/4 to minimize losses as the vapour pressure margin is low and we will need close to full discharge in the seal chamber..but our connection on the casing is 1/2NPT..if we have a 1/2Px3/4T connector, does this not restrict the flow? Should we go with...

Could anybody be kind enough to explain to me what is a fluid film load support..I was looking at an FEA completed for the washer and seat and the results have load support..what is this and what is significant about this? What are the factors which effect this?

Why would it be better to have the shaft in tension as opposed to compression? Whats the benefit? Also, by having a higher pressur between the impeller and throat bush, are we not have a net thrust towards the impeller? How does this really balance? Sometimes I hear they plug only one or two...

Could somebody please explain to me the reason behind removing the back wear rings and balance holes on a high suction, end suction pump? I know it is to balance thrust force, but how does this happen in theory? By having higher pressure between impeller and throat bush are we not having a...

Thank Airsporter1st! Just for my personal knowledge..could you explain your point #2..how would cavitation occur?

The pumping ring is in the direction of flow..but with another piece of metal piggy backed on the seal head..are we not creating a higher centrifugal force as well which is perpendicular to the flow? Also we have close 0.062" clearance between the pumping ring OD and the gland bore..will this...

Sorry..to add..I understand for a Plan 54 no pumping ring is required, but a seal sold to the customer has this but we found out too late the API plan is 54..now they are asking if they could use the same seal w/pumping ring with the plan 54

What is disadvantage of having an axial scroll pumping ring on O/B seal of dual seal...but have a plan 54? This is a horizontal pump..if the external pump is creating flow of say 3GPM and the pumping ring is <3GPM, is this hindering the flow rate? What would happen?

We were testing a dual - tandem metal bellows seals (rotating seal heads) on a vertical pump..the outboard seal has a pumping ring for the plan 53B barrier fluid..we had injected the barrier into the seal at the location of 2 O'Clock and piped up the barrier out at 12 O'clock..the seal squealed...

We are being asked to size of the orifice for API Plan 76 where the vapour is being directed to either flare or a vapour recovery system. 1. Whose responsiblity is it to supply orifice size, seal vendor, pump vendor, or end user? 2. What factors are considered when calculating orifice size...