Features of the B177 External
Automatic Bypass Valve
The CORKEN B177 external bypass valve is designed to
maintain a constant differential pressure across a sliding
vane pump or any other piece of equipment requiring
differential pressure control. Since horsepower is directly
related to the amount of differential pressure generated by
a sliding vane pump, limiting pressure limits horsepower.
This is particularly important on electrically driven pumps
used to load or unload product from bobtails or transports. If
a valve is inadvertently closed, it can overload the motor or
cause the pump to build too much pressure. To prevent this
from happening, an external bypass valve is installed in the
piping system.
To ensure optimum performance of the external bypass
valve and the entire pumping system, follow the instructions
in this manual.
Installation of the B177 External
Automatic Bypass Valve
The B177 external bypass valve may be installed in either
a vertical or horizontal position. Figure 1.1 illustrates how
the B177 is installed as a pump differential bypass valve.
The minimum size of the inlet and outlet piping should not
be smaller than the opening of the external bypass valve.
The outlet piping of the external bypass valve should return
to the liquid or vapor section of the storage tank.
Do not
connect the outlet piping of the external bypass valve
to the inlet piping of the pump .
NOTE: A balance line must connect the valve bonnet
to the storage or supply tank. The minimum size for the
balance line is indicated in the following table.
Valve Model
Minimum Balance Line Tubing Size
B177-2
B177-2.5
1/2"
Operation of the B177 External
Automatic Bypass Valve
The differential pressure setting of the B177 external bypass
valve is adjustable. The range of differential pressure
depends on the size of the spring installed in the bypass
valve. When the bypass valve ships from the CORKEN
factory, a tag identifying the spring size is attached to the
valve bonnet. The table below shows the part number
and differential pressure range for each spring. All of the
springs are interchangeable with each valve size.
Valve Model
Spring Number
Differential
Pressure (PSIG)
B177-2
B177-2.5
1783
10–40
1785
30–80
1786
80–110
1786-1
100–125
Figure 1.1: Typical installation.
5
Summary of Contents for B177-2
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