Suction And Discharge Valves

Valves are manufactured with the use of low-weight materials and have a short lift so that they quickly open their maximum flow position. They are also short, straight path thread to reduce friction losses incurred in liquids abrupdy change their direction. Valves are designed to minimize the volume needed gap in the cylinder, close tightly, low cost and durable. To facilitate the rapid closing of the valve, the majority of the exhaust valves and some suction valves spring. All of these design features work in the direction of maximum die operating efficiency of the compressor.

In valve design, registered in refrigeration compressors can be divided into four main types: disc, ring plate and reed (flexion). Reed valve type may include floating or flexing a cane. All three types of automatic operation, opening and closing in response to changes in pressure generated by the movement of the piston or the rotor. These valve types are described in the following subsections.

Poppet valve was one of the die first types used in refrigeration compressors. It is essentially a slow speed valve, which limits its use to slow down, open compressors. The valve is similar to the automotive valve except diat its much shorter than the stem. Valve prisoner in a cell, the One drawback all flexion or reed valves type is that they cannot be flush with the valve plate. The presence of their sources, pins and servants requires clearance volume will be increased by all compressors using either ring plate or bending the valves of any design.

The location of the relief valves valves of all compressor tend to be located in the cylinder head. Suction valves are located in the compressor head or crown twice trunk piston. As a rule, the suction valves are located in large compressors, piston, where suction pair enters through the ports in the cylinder wall. With small and medium-sized compressors suction valves tend to be located in the cylinder head. When both valves are located in the cylinder head, the head of casting should be partitioned to permit the separation of the suction and discharge vapors.

Most large compressors are equipped with a secondary security head, which are located in the end of the cylinder and is held in place heavy coil springs. At normal pressure discharge, security head is firmly held by the springs. However, if the slug of liquid or some other noncompressible material enters the cylinder, the security head rises under high pressure, allowing the material to transfer valves per cylinder, limiting the damage of the compressor. In small compressors, discharge valve, as a rule, are designed to provide additional measure of protection against pressure shocks. In large compressors, valves and seats are removable for replacement. In small semi-hermetic compressors suction and discharge valves are usually incoiporated in the valve plate, Assembly, removed and replaced as a unit of...