Bighorn Valve Inc. Successfully Completes Functional Testing of a Manual Magnetically Operated (“Zero Leakage”) Globe Throttle Valve
In March 2016, Bighorn Valve Incorporated (Sheridan, Wyoming) was awarded a contract from the Naval Nuclear Laboratory to modify an existing class 2500 globe throttle valve to employ a magnetic operator. Recently, the initial functional testing of the valve was completed. The testing included hydrostatic testing to 5250 psig, stem force measurements as a function of magnetic torque applied, and flow testing including valve operation as a function of differential pressure. The test results met the expected design performance and provide additional proof that the Bighorn valve design and construction methods are suitable for producing commercial valves for zero leakage service. The following photograph shows the modified valve.
Testing showed that the valve operator was able to provide ~1770 lbf of seating force with ~100 in-lbf of magnetic torque. As a result of this design work, methods to substantially improve (3x) this seating force have been determined.
The following plot shows force transmitted as a function of rotation of the magnetic coupling. The measured values were consistent with the modeled values. It should be noted that once the maximum torque is reached, the magnetic coupling releases due to pole slip and the maximum seating force is limited. This is seen as a valuable design feature in that it provides inherent over-torque protection, eliminating the use of cheater bars and the snapping of valve stems. Should higher torques be desired, either a different (magnetically stronger) operator can be used or the existing operator can be engaged over a longer length.
"We are pleased with the successful operational test of this unit, and look forward to continued design improvements to extend the application of this zero leakage valve technology," commented Kevin Burgess, CEO Bighorn Valve Incorporated.