Plate & Frame Heat Exchanger Leaking...

[murphymok]

Hi,

I have a small plate and frame heat exchanger that pre-heat the domestic water with low pressure steam. It is leaking from the holding bolt connection(the threaded bolt that is used to hold the plates together). What will be the cause? Does it need regasket and recondition of the plates?

Thanks in advance.

 

[EnergyRat]

Hi there:

I always avoided plate and frames for steam service, after seeing one leaking steam. However, I have since been told that they work very well in an application such as yours. However, you have to very careful not to overtorque the bolts holding the plates together. In a liquid to liquid application, most some mechanics tend to simply overtorque the bolts to be on the safe side, without using much care.
This will warp the plates and lead to a leaking heat exchanger.

Not sure how to fix the problem, but I would suggest unbotling the plates, determine which are warped, replace these (if not all), then re-assemble, strictly observing the manufacturer's recommended torque specifications.

Best of luck

 

[rmw]

A P/F hx has a specific dimension to which it is to be compressed. Is yours where it is supposed to be, or too loose, or too tight?

rmw

 

[EdStainless]

You need to hope that it is a gasket replacement job.
It could be a few things.
1. as mentioned, it could be over torqued and distorted. The gaskets will have some compression set so replace them.
2. The gaskets could be the wrong material and be loosing resiliancy as they age. If the gaskets are stiff you need to change elastomers.
3. The worst case, you could have crevice corrosion under the gaskets. For the short term this would require that you replace some plates. For the long term you need to look at other alloys for the plates. Just because it is potable water doesn't mean that it isn't corrosive.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[PHEs]

Hi murphymok


I would try the following steps:

1 Steam inlet at the top.
2 Clamp to the minimum measure, between the frame plates, this measure is often stated on the machine plate, and on the assembly drawing.And try again.
3 If you don’t have the measure, you had to ask the manufacture for the measure per/ plate and multiply with the number of plates, (if some plates are taken out).
And try again.
4 If you can get the measure, find the leak and take the plate before and the plate after the leak out, (always 2 plates, a plate pair), and clamp to the new measure according to the new number of plates. And try again.
5 If you don’t know the manufacture, but have spare gaskets, you can find the measure, by clamping the plate pack together without gaskets in, to metallic contact
to high torque at the bolts.

Good luck
PHEs