Cartridge logic valves.

Cartridge logic valves

These are simple two position Open/Shut valves using a poppet and seat. Figure 4.46 shows the construction and symbol for a nor­ mally open (pilot to close) valve. A normally closed (pilot to open) valve can be constructed as Figure 4.47.

Because a cartridge valve is a two position valve, four valves are needed to provide directional control. Figure 4.48 shows a typical circuit for moving a cylinder. Note these are operated in pairs by a solenoid operated two position valve; 2 and 4 cause the cylinder to extend and 1 and 3 cause the cylinder to retract. As drawn the cylin­der will drive to a fully extended or fully retracted position. If the cylinder was required to hold an intermediate position the single

Control valves-0127Control valves-0128

two position solenoid valve would be replaced by a three position centre blocked valve with one solenoid for extend and one for retract.

At first sight this may be thought over complex compared with the equivalent spool valve circuit, but cartridge valves have some

Control valves-0129Control valves-0130

Figure 4.48 Direction control using four cartridge valves. As shown the cyclinder will fully extend or fully retract. If two solenoid valves are used, one for open, one for close, the cylinder can hold position

distinct advantages. Because of their construction they have very low leakage and can handle higher flows than spool valves of a similar size. They are also modular and are connected by screwing into a pre-drilled manifold. This provides high reliability and easy fault diagnosis and replacement. They are commonly used on mobile plant and with water based fluids where leakage can be a problem.

Related posts:

Pumping system hydraulic characteristics:Pump curves and Pump operating point.
Compressed Air Transmission and Treatment:Pressure gauges and indicators.
Air flow rate evaluation:The influence of pressure and System influences.
Air movers:Air compression effects and Delivery temperature.
Gas–solid separation devices:System considerations and Blow tank systems.
Health and safety:Conveying systems and Closed systems.
Low pressure and vacuum:Hopper off-loading and Trickle valves
Erosive wear:Hard materials and Particle concentration
Introduction to pneumatic conveying and the guide:Nomenclature
COMPRESSORS:Axial Compressors
MAINTENANCE OF HYDRAULIC SYSTEMS:MEASURING SUCCESS.
Pneumatic piping, hoses and connections.
Servo valves.
Fundamental Principles:Fundamental Principles
PROPERTIES OF PURE SUBSTANCES:THE IDEAL-GAS EQUATION OF STATE

Leave a comment

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