Loading valves.

Loading valves

Expression 2.2 shows that allowing excess fluid from a pump to return to the tank by a pressure relief valve is wasteful of energy and can lead to a rapid rise in temperature of the fluid as the wasted energy is converted to heat. It is normally undesirable to start and stop the pump to match load requirements, as this causes shock loads to pump, motor and couplings.

In Figure 2.18, valve V1 is a normal pressure relief valve regulat­ing pressure and returning excess fluid to the tank as described in earlier sections. The additional valve V2 is opened or closed by an external electrical or hydraulic signal. With valve V2 open, all the pump output flow is returned to the tank at low pressure with minimal energy cost.

Hydraulic pumps and pressure regulation-0048

When fluid is required in the system the control signal closes valve V2, pressure rises to the setting of valve V 1, and the system performs as normal. Valve V2 is called a pump loading or a pump unloading valve according to the interpretation of the control signal sense.

Related posts:

Pumps:Reciprocating pump types
Low pressure and vacuum:Hopper off-loading and Trickle valves
Air movers: Types of air mover and Aerodynamic compressors.
Air movers:Specification of air movers
Low pressure and vacuum:Gate lock valves
Low pressure and vacuum:Rotary valves and Drop-through valve
Introduction to pneumatic conveying and the guide:Industries and materials and Mode of conveying
Hydraulic fluids:Fire-resistant fluids
Hydraulic accessories:Heat exchangers
Maintenance and troubleshooting:Safety
Hydraulic Pumps and Pressure Regulation:Pressure regulation
Air Compressors, Air Treatment and Pressure Regulation:dynamic compressors
Sequencing Applications:Pneumatic limit switches
POWER AND REFRIGER A TION CYCLES:AN OVERVIEW OF RECIPROCATING ENGINES
POWER AND REFRIGER A TION CYCLES:DEVIATION OF ACTUAL VAPOR POWER CYCLES FROM IDEALIZED ONES

Leave a comment

Your email address will not be published. Required fields are marked *