Introduction to Pressure Regulating Valves and Their Working Principle

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What is a pressure regulating valve? The pressure regulating valve is a combined assembly consisting of a pressure regulating valve, an oil-water separator, and a check valve. Valve types are classified based on their purpose and function, key parameters, pressure, operating temperature of the medium, special applications, driving energy source, and structure. The most common classification method is to divide control valves into nine major categories according to their structure: 6 types are of straight-stroke type and 3 types are of rotary-stroke type. Working principle of the pressure regulating valve: The principle behind this valve relies on the balance between spring force and pressure. When the pressure exerted by the spring is less than the air pressure, the valve remains closed. When the pressure exceeds the spring’s force, the compressed air beneath the rubber pressure-regulating diaphragm exerts a force on the diaphragm, causing it to arch upward and move away from the valve seat, thereby allowing air to flow into the air chamber. At this point, the unloading piston moves under the influence of the air pressure, pushing the discharge valve away from its seat; as a result, the air filled into the air chamber by the air compressor is discharged into the atmosphere through the discharge valve and exhaust port, causing the air compressor to run idly. The difference between a pressure regulator and a safety valve: A pressure regulator is a valve that regulates and controls the output pressure, while a safety valve is a valve that protects equipment when the pressure exceeds the specified safe level; it opens automatically once that pressure limit is reached. A safety valve releases excess pressure when it reaches a critical value. This release of excess pressure should not be confused with that of a pressure regulator, as a pressure regulator is used to adjust pressure, whereas a safety valve serves as a protective mechanism against overpressure in cases of failures elsewhere or blockages in the pipelines. Safety valves cannot be used as control valves. The protection factor of a safety valve is determined based on industrial and operational conditions, and it can be adjusted according to specific parameters. If all pressure is relieved or only excess pressure is removed, such a device can at most be called a protection valve. Control valves come in various forms, including manual, automatic, and micro-controlled types; under strict industrial and operational conditions, it is not recommended to use safety valves as substitutes.