Different Types of pressure controller

No matter which pneumatic or hydraulic system you see, you will find pressure controller valves in almost all the systems and as the name suggests, their main purpose is to control pressure. From keeping the system pressure below a particular limit to maintaining a particular pressure level in the part of the circuit, pressure controllers have a variety of different and useful functions which is why they are required in most of the industries. Pressure controllers are even used in critical equipment like ventilators and anesthesia machines which require consistent flow of pressure at all times, failing which can cause fatal injuries or even deaths to patients.

There are different types of pressure controllers and each one has different usage as per the requirement of the industry. Each type of controller is discussed in brief below.

Pressure relief valves

Most of the systems whether they are pneumatic or hydraulic are designed in such a way that they work within a specific and defined range of pressure. The forces generated inside the system due to excess pressure must be controlled so that the expensive and critical components of the system could be saved from getting damaged. Pressure relief valves do this job perfectly by limiting maximum pressure in the system as they divert the excess gases whenever pressure in the system either crosses the desired limit or gets too high.

Sequencing valves

It becomes important to move actuators in a specific order or a sequence in the circuits that have more than one actuator and digital control devices like timers, limit switches etc can do this job. Sequencing valves resemble direct acting relief valves and the difference lies in the draining of their spring chambers. Their spring chambers are drained externally instead of internally where lies the major difference. This Sequencing valve allows pressure to flow to the second function only after the first or the priority function has been completed successfully first. A sequence valve when closed allows gas to flow freely to the primary circuit so that the first or the primary function is fulfilled and satisfactorily performed

Pressure reducing valves

The pressure reducing valves are the most common types of valves used to maintain pressure across pneumatic and hydraulic systems. These types of valves are usually two-way open valves which are closed when there is a sufficient downstream pressure in the system. Direct acting and pilot operating valves are the two types of pressure reducing valves. In direct acting pressure reducing valves, the maximum pressure available in the secondary circuit is limited regardless of the change in pressure in the primary circuit whereas in case of pilot operating valves, the spool is balanced by downstream pressure at both ends hydraulically. In order to ensure that the flow through the main valve equals the overall requirements of the circuit with the reduced pressure, the pilot valve relieves enough gas to position the spool.

Counterbalance valves

In order to counterbalance a weight, these counterbalance valves are used to maintain a desired pressure in the particular portion of a circuit. These valves are typically closed where the primary port of the valve is connected to the rod end of the cylinder while the secondary port is connected to the secondary directional control valve. To avoid the risk of the free falling of the load, the pressure is set slightly higher than what is required. The cylinder extends and increases pressure at the rod end when the pressurized fluid flows through the cap end of the cylinder. This process shits the main spool in the valve.