Selection of throttle valve

The main functions of the sequence valve are: (1) Control the sequence action of multiple components; (2) Used in the pressure holding circuit; (3) Prevent the cylinder piston from falling due to its own weight and be used as a balance valve; (4) Use external control sequence The valve is used as an unloading valve to unload the pump; (5) The internal control sequence valve is used as a back pressure valve. The selection of sequence valve: The sequence valve can realize different return sequence valves according to the different assembly structure. The main functions of the sequence valve are: (1) Control the sequence action of multiple components; (2) Used in the pressure holding circuit; (3) Preventing factors Self-weight causes the cylinder piston to fall and use it as a balance valve; (4) Use an externally controlled sequence valve as an unloading valve to unload the pump; (5) Use an internally controlled sequence valve as a back pressure valve. Selection of sequence valve: Sequence valve can realize different circuit functions, such as overflow valve, sequence valve and balance valve according to the different assembly structure. If the opening and closing characteristics of the sequence valve are too poor, the pressure will be too high when the flow is large, and the efficiency of the circuit will decrease. The opening and closing has a hysteresis loop, the opening pressure is lower than the closing pressure, and attention should be paid when the load flow changes. Open the valve with too low pressure, and when the pressure is lower than the set pressure, forward leakage will occur, causing the actuator to malfunction. When the flow rate through the valve is much smaller than the rated flow rate, vibration or other instability occurs. At this time, measures must be taken on the loop. 1) Selection of valve type Regulating valve The best choice for valve type is a fully functional, light-weight, full-featured ultra-light regulating valve to replace other regulating valve products, which can simplify the selection of futures products due to incomplete functions and worry about improper selection (such as straight stroke) The problem of anti-blocking of similar valves; the relationship between cut-off and pressure difference, etc.) troubles. 2) Selection of actuators Selection of actuators: ①Select imported electronic actuators to overcome a series of unreliability problems; ②Use fine and small series for membrane type actuators; ③Consider the gear and pinion type for piston type actuators; ④Tell the valve The closed pressure difference is determined by the size of the actuator selected by the manufacturer. 3) The choice of materials This issue is more complicated. Since many corrosive media do not corrode PTFE, it is advisable to choose a full tetrafluoroethylene corrosion-resistant valve, which greatly simplifies the selection of corrosion-resistant occasions, but when the temperature is >180 ℃, <-40 ℃, PN≥2.5KPa At the time, consider the corrosion-resistant alloy. 4) Selection of spring range For valves equipped with membrane actuators, positioners are now installed in most occasions, which can make full use of 250KPa air source. Choose a spring with medium stiffness and large output force of 60～180KPa. ; Similarly, choose 150～300KPa for the piston actuator. 5) Flow rate selection ① When the parameters are inaccurate, choose logarithmic special: ② When the response speed of the system to be adjusted is fast, such as flow adjustment, liquid pressure adjustment , Choose the logarithmic special; when the response speed of the system is slow, select the liquid level system, the temperature regulation system, and the linear special; ③ When the S value is small, choose the logarithmic special; ④ When the valve may work with a small opening, choose the logarithmic special.