Showing posts with label Pratt Industrial. Show all posts
Showing posts with label Pratt Industrial. Show all posts

Thursday, August 30, 2018

An Introduction to Triple Offset Butterfly Valves

Triple Offset Butterfly Valves
Triple Offset Butterfly Valve
(Pratt Industrial)
Triple offset butterfly valves are designed to fill the demand for an alternate solution to gate valves and ball valves. They are preferred when weight, space, performance, and the ability to modulate to the process flow are an issue. Typically available in sizes 3" through 48", and in 150, 300 and 600 pressure classes, they're rated for operation from -50 deg. F. through 750 deg. F.

Designed with metal-to metal seats, triple offset butterfly valves provide distinct advantages over traditional gate valves, namely lower weight, zero-leakage, ease in automation, and capable of being used for modulating service.

Industries Using 
  • Chemical
  • Refinery
  • Power
  • Steam Generation
  • Petrochemical
  • Water/Waste Water Treatment
Triple Offset Butterfly Valves
Click on image for larger view.
Triple Eccentric Disc-Shaft Design (diagram above)
  • Offset 1: It is accomplished by moving the centerline of the shaft away from the seating plane.
  • Offset 2: It is accomplished by moving the centerline of the shaft offset from the centerline bore of the valve.
    • These two design features cause the disc to open and close relative to the body seat in a “camming” action and effectuate the position seated valve design which is typical of the High Performance Butterfly Valve, however there is still contact between the disc and the seat in the first several degrees of opening and closing which can cause premature wear of the seat in the general areas.
    • In order to achieve an API 598 Shut Off classification a 3rd offset needed to be introduced to make the valve a “torque seated” design with graphite and metal seating surfaces.
  • Offset 3: It is accomplished by adjusting the cone angle created by the 1st and 2nd offset angles at some point downstream of the valve in the center of the piping to the adjacent piping wall as depicted in the illustration below “Sticking tendency”. By incorporating the 3 offsets into one design typical of gate valves is eliminated with seat contact throughout the entire stroke reducing run torques and improving actuator modulating performance at the same time.
For more information, contact Piping Specialties by visiting https://psi-team.com or by calling 800-223-1468.

Saturday, September 30, 2017

Disassembling the Pratt Industrial BF Series Resilient Seated Butterfly Valve

On an earlier video we demonstrated how to assemble the Pratt BF Series butterfly valve. In this video we demonstrate how to DISASSEMBLE the valve.


The Pratt BF Series butterfly valve is the resilient seated butterfly workhorse for these industries:
  • Mining
  • Food/Beverage
  • Power
  • OEM’s
  • Chemical/Pharmaceutical
  • Desalination
  • Petroleum/Oilfield
  • Ultra Pure Water
  • Transportation
  • Marine
  • Irrigation
  • HVAC
Sizes: 2" through 48"
Body: Ductile Iron (65-45-12)
Disc: Ductile Iron Nickle Plated, Ductile Iron Nylon 11, CF8M Stainless Steel, Aluminum Bronze
Stem: 416 S.S. Heat Treated
Resilient Seat: EPDM, Buna-N, Viton
Actuation Options: Worm Gear, Lever, Pneumatic, Electric
Pressure Ratings: 2" – 12" 230psi; 14" – 48" 150psi

Features:
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• Innovative 3 point connection, tongue andgroove seat allows for higher pressure rating and full Vacuum service
• Unique secondary shaft seals prevent leakage from shaft.
• Two piece shaft design provides maximum strength and a high flow characteristic disc.

For more information, visit http://www.psi-team.com or call Piping Specialties at 800-223-1468.