Expansion joints for fan application
Expansion joints for fan application
(OP)
I am working on an industrial fan application. These are 50 hp, 1800 rpm, 10,000 cfm fans operating at a pressure of 57" WG.
The fans are mounted using vibration isolators on structural steel. There are flanged connections to both the suction and discharge ductwork. Maximum vibration is 68 mils.
In the fan manufacturers documentation they are saying that expansion joints are required on fan inlet and outlet. The problem is that I have extremely limited space as it is. I am planning to simply use approx. 1/2" rubber gasket between the flanges on both inlet and outlet.
Just wondering what some of your thoughts are on going this route instead of one of the commerically availble expansion joints.
Thanks.
The fans are mounted using vibration isolators on structural steel. There are flanged connections to both the suction and discharge ductwork. Maximum vibration is 68 mils.
In the fan manufacturers documentation they are saying that expansion joints are required on fan inlet and outlet. The problem is that I have extremely limited space as it is. I am planning to simply use approx. 1/2" rubber gasket between the flanges on both inlet and outlet.
Just wondering what some of your thoughts are on going this route instead of one of the commerically availble expansion joints.
Thanks.





RE: Expansion joints for fan application
regards
Dave
www.wsec1.com
RE: Expansion joints for fan application
Whatever you end up doing, store bought expansion joints or shop built, (both work) they should accomplish the purpose of isolating the fan from the duct loads.
No situation that I have ever seen with enough duct expansion that required EJ's would have been solved with a 1/2" piece of rubber gasket between the flanges (which is what I interpreted you to have said, as opposed to a stand off type EJ made out of 1/2" think rubber.)
You did not give a temperature, but 57" wg is not necessarily a plain vanilla EJ. Be careful. If it is air at ambient temps, don't forget internal EJ's if your duct is large enough to get into.
rmw
RE: Expansion joints for fan application
Sample spec, with some basis in practicality -
Fans and Air Handling Units:
1. Such units shall have electrical flexible connections not less than 36" long and the flexible duct connections with a free length of not less than 8".
RE: Expansion joints for fan application
rmw
RE: Expansion joints for fan application