Flowserve BB 1 - Manual (Page 5)

5
Swing and dual-plate check valves BB feature two separately suspended semi-circular plates pivoting
on an independent hinge pin. The two plates open and close automatically allowing fluid to flow
in one direction only. The opening pressure and closing time can be customized by modifying the
spring characteristic. Hydraulic dampers are also available as optional extras to solve waterhammer
problems. Installation in any position, with due regard to our installation recommendations. Our
dual-plate check valves are fitted with eyebolts for easy installation and transit protection.
Please note that dual-plate check valves should not be used on reciprocating compressors, piston
pumps or where pulsating flow exists.
The low opening pressure of the dual-plate check valves is a function of the spring characteristics.
When the opening pressure is reached the hinge sides of the plates open first, thereby eliminating
any possibility of the seats scuffing. As the pressure and flowrate rise, the opening angle increases
symmetrically. Media entering the valve at an unfavourable angle (e. g. due to pipe bends) may cause
an asymmetrical opening of the plates. If centrifugal pumps are installed upstream of the valve it
becomes necessary to arrange for a defined stabilizing section. Systems where pulsating flow exists
require specially designed dual-plate check valves. Make sure to install valves that are not fitted with
springs in a vertical position with upward flow. Please note the installation recommendations outlined
in the following pages.
Function
Scope of supply
Explanatory Notes
BB 1...
 Dual-plate check valve type BB ...
 Installation manual
BB 2...
 Dual-plate check valve type BB 2...
 Installation manual
BB 1... D
 Dual-plate check valve type BB ... with dampers
 Installation manual
BB 2... D
 Dual-plate check valve type BB 2... with dampers
 Installation manual
Description