Composition and working principle of pneumatic three-way ball valve

Reference in design, selection and maintenance The original design of a continuous crystallization device is that each mold uses two pneumatic switch ball valves to control the recovery and reflux of its internal materials When the device operates in automatic mode, the two valves will switch alternately according to the change of liquid level in the mould However, the process has two shortcomings: first, when a valve is closed for a long time, low-temperature materials will crystallize in the pipeline in front of the valve, causing local blockage; second, when any crystallizer needs to be repaired due to failure, the whole device must be shut down, resulting in the reduction of equipment utilization Therefore, the author has carried on the technical transformation to it, replaced the original two billiard ball valves with one three-way valve, and redesigned the control scheme, and achieved the expected effect after the actual operation 1 The continuous crystallization process after modification is shown in Figure 1 It can be seen from the figure that the material is first pumped into the mould a from the raw material tank through the feed pump (delivery pump) for cooling and cooling; the cooled material is then turned over from the mould a to the mould B through the turnover pump for further cooling and cooling; and so on, the material is turned over to the mould f for further cooling and cooling; After Zui, the material containing crystal in crystallizer f is sent to the centrifugal separation process by turning over pump for centrifugation, drying and packaging to obtain qualified products Three way valve is used to control the liquid level of each crystallizer: when the liquid level in the crystallizer is higher than the high set value, the material will be automatically turned over to the next level crystallizer through the DCS control valve; when the liquid level in the crystallizer is lower than the low set value, the DCS control valve will automatically recycle The cooling water quantity of each mould is controlled by the regulating valve to ensure the cooling temperature When any mould needs maintenance, the operator only needs to press the maintenance button as shown in Fig 2 in the manual state, open the manual bypass valve on site, and close the manual feed valve and manual return valve At this time, the material will go directly from the upper crystallizer to the next crystallizer through the valve, and it will be separated from the system for maintenance 2 Composition and working principle of pneumatic three-way ball valve pneumatic three-way ball valve is composed of solenoid valve, three position pneumatic actuator and three-way valve body The principles and functions of each part are described as follows 2.1 The structure and principle of the solenoid valve, no matter it is a two position or three position pneumatic actuator, need to use the solenoid valve to control the air circuit switching and realize the valve opening and closing action For the solenoid valve reversing after the single electric control coil is powered on, the solenoid valve resets under the action of the spring in the valve after power loss 8-12mm copper pipe (plastic pipe) connection or Namur connection can be used between solenoid valve and actuator cylinder According to the different internal structure, the solenoid valve can be divided into two position three-way valve and two position five way valve The solenoid valve in the two position three-way working mode includes an air inlet (connected to the air source), an air outlet (supplied to the air source of the cylinder) and an air outlet (installed with a muffler) It is usually used together with a single acting cylinder to realize the two position control of the valve opening and closing; The solenoid valve with two position five way working mode has one air inlet (connected to the air source), one positive acting air outlet and one negative acting air outlet (respectively providing one positive and one negative acting air source for the cylinder), one positive acting air outlet and one negative acting air outlet (both equipped with silencers) It is usually used in conjunction with the double acting cylinder to realize the two position control of valve opening and closing System The voltage level of solenoid valve coil generally adopts 24V (DC), 220V (AC), etc., and it can be divided into explosion-proof and non explosion-proof.