Two-position regulating butterfly valve
Addtime：2021-09-02 From： View：411
Overview
The pneumatic two-position butterfly valve is the core control component in the gas-air ratio regulating actuator of the mobile hot treatment furnace. It is also a part with a relatively high failure rate in the control system of the hot treatment furnace. The understanding of the actuator's principle, operation, and environmental factors directly affect whether the actuator can work properly. At the same time, it can lead to significant fluctuations in the quality of the hot treatment process, thereby increasing the quality cost.
Working principle
The pneumatic two-position butterfly valve consists of a pneumatic actuator and a butterfly valve.
The pneumatic actuator is composed of two single-acting cylinders combined into one unit. It is controlled by two pilot solenoid valves to achieve two opening degrees of 45° and 90°. In each cylinder, there is a set of piston limit adjustment mechanism to control the piston stroke, converting linear motion into circular motion, thereby enabling the butterfly valve to be adjustable within the opening ranges of 0~45° and 45°~90°.
The butterfly valve is composed of the valve body, valve plate, shaft, connecting rod, etc. It converts the stroke position of the piston rod into the opening degree of the valve plate, and has a pointer-type display device to directly read the opening degree value. The starting angle of the valve plate is 150°. When the display is 750°, it is the maximum opening value. The main technical parameters of the pneumatic two-position butterfly valve for the belt conveyor furnace are as follows. Torque limiting mechanism: used to regulate the torque (or thrust) and keep it within the predetermined value.
Factors Affecting the Operation of Pneumatic Two-Position Control Butterfly Valves
Based on years of production experience, the reasons for the malfunction of pneumatic two-position butterfly valves during operation are diverse. There are factors related to improper operation, as well as structural factors that do not adapt to the environment. The analysis is as follows.
(1) Pressure and air source have an impact on pneumatic two-position butterfly valves. When the system pressure is lower than 0.1 MPa, it will cause the pneumatic two-position butterfly valve to malfunction. This indicates that the pneumatic two-position butterfly valve has a narrow range of pressure adaptation. Expanding its pressure adaptation range is one of the means to reduce the failure rate. During the fault handling process, it is often found that the filter and the air passage of the electromagnetic pilot valve are blocked, resulting in insufficient pressure. The main reason is that the compressed air contains excessive free dust. Pneumatic two-position butterfly valves must have pure air during operation. To ensure smooth operation, the air must be purified.
(2) Environmental factors have an impact on pneumatic two-position butterfly valves. Based on years of production experience, pneumatic two-position butterfly valves have strict requirements for the working environment. They require a clean environment without dust or smoke. This is undoubtedly a difficult problem for large enterprises in their heat treatment processes. Especially in the northern winter with low temperatures, the air passages of the filter and the electromagnetic pilot valve often freeze and become clogged, causing the pneumatic two-position butterfly valve to malfunction. This increases the downtime of the heat treatment furnace equipment and reduces production efficiency.
(3) The influence of the actuator of the pneumatic two-position butterfly valve. In the heat treatment process of cast steel, to ensure good mechanical properties of the cast steel, the temperature control of the gas-fired heat treatment furnace is very strict, as shown in Figure 1. The pneumatic two-position butterfly valve is the most important actuator for temperature control in the gas-fired heat treatment furnace. It adjusts the flow of the air source to achieve the purpose of temperature control. Operators constantly adjust the flow of the air source according to the displayed temperature curve. The actuator of the pneumatic two-position butterfly valve frequently operates, causing wear on the sealing elements. Especially in the equalizing and insulation zones, to ensure temperature balance, the switching action is more frequent, with 8 to 10 switching actions per minute. Under the condition of 22 days of operation per month and three shifts per day, the actuator of the pneumatic two-position butterfly valve is severely worn. Due to continuous production, the external temperature of the furnace body keeps rising, and the actuator elements are aged by heat. Ensuring the normal operation of the actuator is the key to avoiding faults in the pneumatic two-position butterfly valve.
(4) Maintenance and upkeep have an impact on pneumatic two-position butterfly valves. Due to the frequent occurrence of faults in the pneumatic two-position butterfly valve, it is necessary to perform maintenance and upkeep to ensure production. During each disassembly and installation process, the positions of the large and small cylinders must be re-adjusted and positioned, resulting in an increase in the angle displacement of the butterfly valve. This further increases the failure rate of the pneumatic two-position butterfly valve.
The pneumatic two-position butterfly valve is the core control component in the gas-air ratio regulating actuator of the mobile hot treatment furnace. It is also a part with a relatively high failure rate in the control system of the hot treatment furnace. The understanding of the actuator's principle, operation, and environmental factors directly affect whether the actuator can work properly. At the same time, it can lead to significant fluctuations in the quality of the hot treatment process, thereby increasing the quality cost.
Working principle
The pneumatic two-position butterfly valve consists of a pneumatic actuator and a butterfly valve.
The pneumatic actuator is composed of two single-acting cylinders combined into one unit. It is controlled by two pilot solenoid valves to achieve two opening degrees of 45° and 90°. In each cylinder, there is a set of piston limit adjustment mechanism to control the piston stroke, converting linear motion into circular motion, thereby enabling the butterfly valve to be adjustable within the opening ranges of 0~45° and 45°~90°.
The butterfly valve is composed of the valve body, valve plate, shaft, connecting rod, etc. It converts the stroke position of the piston rod into the opening degree of the valve plate, and has a pointer-type display device to directly read the opening degree value. The starting angle of the valve plate is 150°. When the display is 750°, it is the maximum opening value. The main technical parameters of the pneumatic two-position butterfly valve for the belt conveyor furnace are as follows. Torque limiting mechanism: used to regulate the torque (or thrust) and keep it within the predetermined value.
Factors Affecting the Operation of Pneumatic Two-Position Control Butterfly Valves
Based on years of production experience, the reasons for the malfunction of pneumatic two-position butterfly valves during operation are diverse. There are factors related to improper operation, as well as structural factors that do not adapt to the environment. The analysis is as follows.
(1) Pressure and air source have an impact on pneumatic two-position butterfly valves. When the system pressure is lower than 0.1 MPa, it will cause the pneumatic two-position butterfly valve to malfunction. This indicates that the pneumatic two-position butterfly valve has a narrow range of pressure adaptation. Expanding its pressure adaptation range is one of the means to reduce the failure rate. During the fault handling process, it is often found that the filter and the air passage of the electromagnetic pilot valve are blocked, resulting in insufficient pressure. The main reason is that the compressed air contains excessive free dust. Pneumatic two-position butterfly valves must have pure air during operation. To ensure smooth operation, the air must be purified.
(2) Environmental factors have an impact on pneumatic two-position butterfly valves. Based on years of production experience, pneumatic two-position butterfly valves have strict requirements for the working environment. They require a clean environment without dust or smoke. This is undoubtedly a difficult problem for large enterprises in their heat treatment processes. Especially in the northern winter with low temperatures, the air passages of the filter and the electromagnetic pilot valve often freeze and become clogged, causing the pneumatic two-position butterfly valve to malfunction. This increases the downtime of the heat treatment furnace equipment and reduces production efficiency.
(3) The influence of the actuator of the pneumatic two-position butterfly valve. In the heat treatment process of cast steel, to ensure good mechanical properties of the cast steel, the temperature control of the gas-fired heat treatment furnace is very strict, as shown in Figure 1. The pneumatic two-position butterfly valve is the most important actuator for temperature control in the gas-fired heat treatment furnace. It adjusts the flow of the air source to achieve the purpose of temperature control. Operators constantly adjust the flow of the air source according to the displayed temperature curve. The actuator of the pneumatic two-position butterfly valve frequently operates, causing wear on the sealing elements. Especially in the equalizing and insulation zones, to ensure temperature balance, the switching action is more frequent, with 8 to 10 switching actions per minute. Under the condition of 22 days of operation per month and three shifts per day, the actuator of the pneumatic two-position butterfly valve is severely worn. Due to continuous production, the external temperature of the furnace body keeps rising, and the actuator elements are aged by heat. Ensuring the normal operation of the actuator is the key to avoiding faults in the pneumatic two-position butterfly valve.
(4) Maintenance and upkeep have an impact on pneumatic two-position butterfly valves. Due to the frequent occurrence of faults in the pneumatic two-position butterfly valve, it is necessary to perform maintenance and upkeep to ensure production. During each disassembly and installation process, the positions of the large and small cylinders must be re-adjusted and positioned, resulting in an increase in the angle displacement of the butterfly valve. This further increases the failure rate of the pneumatic two-position butterfly valve.