Selection of gas pressure reducer need to consider a number of factors, we summarise the following five factors.
Ⅰ.Gas type
1. Corrosive gases
If oxygen, argon and other non-corrosive gases, you can generally choose ordinary copper or stainless steel pressure reducer. But for corrosive gases such as hydrogen sulfide, chlorine and other corrosive gases, you must choose corrosion-resistant materials made of pressure reducer, such as Hastelloy or Monel alloy and other materials made of pressure reducer, in order to prevent the pressure reducer from being corroded and damaged, to ensure the safety and normal use.
2. Combustible gases
For flammable gases such as hydrogen, acetylene, etc., choose a pressure reducer specially designed for flammable gases. These pressure reducers usually have special sealing structure and explosion-proof measures, such as the use of oil-free lubrication design, to avoid the contact of lubricating oil and combustible gases caused by fire or explosion hazards.
Ⅱ.Input and output pressures
1. Input pressure range
The pressure range of the gas source needs to be specified. The maximum input pressure of the pressure reducer must be able to fulfil the maximum pressure requirement of the gas source. For example, if the maximum pressure of the gas cylinder is 15MPa, then the maximum input pressure of the selected pressure reducer should be not less than 15MPa, and there should be a certain safety margin, it is generally recommended to select a pressure reducer with the maximum input pressure 10% – 20% higher than the actual maximum pressure of the gas source.
2. Output pressure range
Determine the output pressure range according to the requirements of the actual equipment. Different equipment has different requirements for gas pressure, such as laboratory gas chromatograph may require a stable gas pressure of 0.2 – 0.4MPa, welding equipment may require 0.3 – 0.7MPa acetylene or oxygen pressure. To choose the output pressure range can cover the equipment required pressure reducer, and can accurately adjust the output pressure to meet the fine pressure control requirements of the equipment.
Ⅲ.Flow Requirements
1. Equipment Flow Requirements
Understand the flow requirements of the equipment using the gas. For example, a large industrial cutting equipment requires a large amount of oxygen and gas, its flow rate may reach dozens of cubic metres per hour, it is necessary to choose a high-flow pressure reducer to meet the equipment’s gas supply needs. For small laboratory instruments, the flow demand may be only a few litres per minute, and accordingly a small flow reducer can be selected.
2. Pressure reducer flow parameters
Check the flow parameters of the pressure reducer, usually expressed in terms of the maximum output flow at a specific input pressure. When selecting, make sure that the maximum output flow rate of the pressure reducer can meet the maximum flow demand of the equipment and that the pressure reducer can maintain a stable output pressure within the normal operating flow range of the equipment.
Ⅳ.Precision requirements
1. Pressure regulation accuracy
For some of the pressure accuracy requirements of high precision equipment, such as precision instrument analysis, electronic chip manufacturing and other fields of equipment, need to choose a high-precision pressure regulator function. These pressure reducers usually use high-precision pressure regulating valves and sensitive pressure gauges, which can control the fluctuation of output pressure within a very small range, such as ± 0.01MPa.
2. Gauge accuracy
The accuracy of the pressure gauge on the pressure reducer is also important. A high accuracy pressure gauge can display the pressure value more accurately, which is convenient for the user to adjust and monitor the pressure accurately. The accuracy of pressure gauges on pressure reducers for general industrial use can be around ±2.5%, while for applications requiring high accuracy, the accuracy of pressure gauges may need to be ±1% or higher.
Ⅴ.Safety performance
1. Safety valve setting
The pressure reducer should be equipped with an effective safety valve. When the output pressure exceeds the set safety pressure, the safety valve can open automatically to release the gas, preventing the pressure from being too high to cause damage to the downstream equipment or cause safety accidents. The opening pressure of the safety valve should be adjustable and will not malfunction within the normal operating pressure range.
2. Other safety measures
Some pressure reducers are also equipped with safety features such as overcurrent protection and anti-flameback devices (for flammable gases). For pressure reducers used in special environments, such as in high temperature, humidity or explosion hazardous environments, it is also necessary to consider the protection level of its shell (such as IP rating) to ensure that the pressure reducer can operate safely and reliably.
Post time: Dec-06-2024