Technical Seating Features

Anti-Blowout Stem Design

Upstream Seat:

Line Pressure acting on the seat area (A1)
does not equalize against the line pressure
acting on the seat area (A2). The difference
in the area (D1) times the line pressure
creates “piston effect” force which pushes
the seat against the ball surface resulting in a
tight effective seal.

Downstream Seat:

When the body cavity pressure is greater
than the downstream pressure, the body
cavity pressure acts on the seal area (A4).
The net pressure difference, acting over area
(D2), pushes the downstream seat tightly
against the ball creating a positive seal.

THE ULTIMATE BENEFIT OF USING THE “
DOUBLE PISTON SEAT” DESIGN:

In case of upstream seat leakage, the downstream
seat maintains a pressure assisted tight shut off by
sealing against the ball surface.

PB=Body Cavity Pressure

Self Relieving Seat Design

Upstream Seat:

The difference in the area (D1) times the line
pressure creates a “piston effect” which
forces the seat against the ball surface. Also
the springs behind the seat adds the force to
the seat which keeps the seat in contact with
the ball surface by providing the tight seal.

Downstream Seat:

When the body cavity pressure exceeds the
spring pressure, automatic pressure relief
will occur by relieving the body cavity
pressure past the downstream seat. This
eliminates the need for the body relief valve.

Double Block and Bleed

The double block and bleed condition is
available in all seat design configurations.
When the ball is in the closed position the
body cavity pressure may be drained down to
‘zero’ by opening the bleed valve and
draining the fluid by removing the drain plug.
Each seat works independently assuring tight
shut off seal against ball on the upstream and
downstream side.

PB=Body Cavity Pressure is Zero
Cavity Pressure is Drained or Vented to Atmosphere

 

GET OUR STOCK PRICE LIST
Join our members club to receive discounts, special pricing, and offers only available by signing up here. You will receive a PDF with stock valve pricing emailed to you immediately upon signup.
We hate spam. Your email address will not be sold or shared with anyone else.