Butterfly valves for flow balancing through parallel chiller circuits
Butterfly valves for flow balancing through parallel chiller circuits
(OP)
Hi Everyone,
I'm looking for advice how butterfly valves will perform as good as DRVs ( double regulating valves) in flow balancing through parallel chiller(er) water circuits.The butterfly valve I had is 10 diameter, and propose to replace Oventhop Double regulating valve, as the later is more expensive.
I'm looking for advice how butterfly valves will perform as good as DRVs ( double regulating valves) in flow balancing through parallel chiller(er) water circuits.The butterfly valve I had is 10 diameter, and propose to replace Oventhop Double regulating valve, as the later is more expensive.





RE: Butterfly valves for flow balancing through parallel chiller circuits
Most valves will also allow you to put a mechanical stop, so that it will not go 100% open or shut, if required in your Risk Management.
RE: Butterfly valves for flow balancing through parallel chiller circuits
I just have 4 butterfly valves, that is one per circuit in a 4 chillers parallelcircuit configuration.Any comment/comparison of actual experience between the two types of valves ( cheaper against the expensive. The butterfly valves adjustment is manual and a mechanical stop will be placed to prevent further opening during subsequent normal operation once balancing is achieved for the 4 parallel circuits.
I hope to be able to balance the water flow during commissioning using these butterfly valves as good as but not using the more expensive DRVs, and orifice plates to measure flow during the commissioning stages for balancing.
RE: Butterfly valves for flow balancing through parallel chiller circuits
RE: Butterfly valves for flow balancing through parallel chiller circuits
If you need positive seal off for maintenace, then go fo the better seals. Jim is correct on the offset part, but if you are not moving them much, it's not mandatory.
Here will be your problem when balancing the system. This is not always true, but from experience of such systems. Everyone in the plant will want to adjust the valves and water flow. Pretty soon you'l see a slow decline in performance of the cooling system. What you will find is all the valve will be at some partial closed state. You need to find the loop with the least resistance (shortest line or smallest exchanger, whatever.) and make sure that vale is 100% open, then adjust the other three, do not ever close the that valve.
RE: Butterfly valves for flow balancing through parallel chiller circuits
AS the 4 circuits are parallel connected to headrs on both suction and discharge sides, I would not expect the resistance thr' the chillers appreciably different; and even if there are different resistance, should I not start with manually opening 100% the valve in the circuit with the highest resistance, so that the other 3 circuits ( of lesser resistance) can have the valves manually adjusted to less than 100% open to balance the flows thr' all 4 chilers during commissioning and a stop placed on their opening at position where balance were found.
Wellcome any comment and advice.