In this serie, it contains all kinds of our sealing gaskets. From material, we have PVC material, and also we have EPDM rubber material. From the types, we have H type, J type etc. From the colors, we have gray one, black one and white one. From the sizes, we have so many sizes which can suit for your different door thickness. For detailed information, you can search this serie or directly ask us in any time. Truck Door Seal,PVC Seals,Extruded Rubber Seal Gasket,EPDM Door Sealing Jiaxing Ganland Auto Parts Co., Ltd. , https://www.ganlandparts.com
Air valve common fault and troubleshooting
First, the common problems of air valve: (1) the outlet pressure of the valve is almost equal to the inlet pressure, no decompression: Failure phenomenon: the pressure of the inlet and outlet of the valve is nearly equal, and the outlet pressure is not regulated by the rotation of the pressure regulating handle And change. The cause of this failure and the exclusion method is as follows: ①due to the main valve body or sink hole on the edge of the body bore burr or the gap between the main valve body and the hole in the card there is dirt, or due to the Lord Valve plug or valve hole tolerance tolerance, resulting in hydraulic clamping, the main spool stuck in the maximum opening (max) position, due to the large opening, the oil is not decompression. At this point according to the above circumstances were taken to deburring, cleaning and repair valve hole and spool accuracy method to be ruled out. ② due to the main spool and the valve hole with tight, or pull the valve hole or valve spool assembly, the valve core stuck in the maximum opening position, then the optional clearance. J-type valve with the gap is generally 0. 007 ~ 0. 015mm, with the appropriate before grinding the valve hole, matched spool. ③ The main spool short hole or seat orifice clogging, loss of automatic adjustment function, the main valve spring force will push the main valve to the maximum opening, into a straight through, the inlet pressure equal to the outlet pressure. Available φ1. Omm steel wire or compressed air through the orifice, and cleaning and reassembly. ④ J-type pressure reducing valve with damping orifice damping member is pressed into the main spool, the use may be due to insufficient interference and out. After flushing, the pressure in the oil inlet chamber and the oil outlet chamber are equal (no damping), while the force area in the upper and lower spools is equal, but the oil outlet cavity has a spring, so the main spool is always in the position of maximum opening, The pressure is equal to the inlet pressure. In this case, rework the slightly larger outer diameter damper and re-press the main spool. ⑤ JF-type valve, the factory drain Drainage L is blocked with a plug. When the plug is not used out of use, make the main valve cavity (spring cavity) trapped in oil, resulting in the main valve opening at maximum pressure without decompression. J-tube valve with the same. J plate valve If the design of the mounting plate did not make the L port connected to the oil pool will also appear this phenomenon. ⑥ on the J-tube valve, it is easy to remove the valve cover installed in the wrong direction (wrong 90 ° or 180 °), the leakage port blocked, unable to drain oil, resulting in the same trapped oil phenomenon, so that the main valve At the maximum opening without decompression. When repairing the bonnet assembly direction can be installed. ⑦ on the JF-type pressure reducing valve, the top cover installed in the wrong direction, will make the output hole and drain holes connected, resulting in no decompression, also must be noted. (2) Symptom two: the outlet pressure is very low, even tighten the pressure regulating hand wheel, the pressure rise can not rise; cause of this failure and troubleshooting are as follows: ①relief valve inlet and outlet reversed: the plate valve There was an error in the design of the mounting plate and the pipe valve was taken over. J-type valve inlet and outlet with the Y-type relief valve out of the port exactly the opposite. Users should pay attention to the mark on the valve near the port mark (Pl, P2, L and other words), or access to hydraulic components catalog, not design errors and wrong. ② inlet pressure is too low, after the relief valve spool orifice, the output pressure from the oil outlet is lower, this time should identify the cause of the low inlet pressure (such as relief valve failure). ③ pressure relief valve downstream loop load is too small. Pressure can not be established at this time can be considered in the downstream of the pressure reducing valve in series to solve the throttle. ④ Pilot valve (cone valve) and the valve seat with the surface due to the retention of dirt and poor contact, do not meet; or pilot cone valve has a serious scratch, valve seat with larvae L out of round, a gap, resulting in pilot valve core Not fit with valve seat hole. ⑤ disassembly, missing cone valve or cone valve is not installed in the seat hole. In this regard, you can check the cone valve assembly or close situation. ⑥ The main orifice on the main damping orifice clogged with dirt, as shown in Figure 3-21, P2 cavity of the oil can not flow through the long damping orifice e flow into the main valve spring cavity, the feedback pressure P2 of the delivery chamber less than the pilot cone Valve, the pilot valve to lose the main valve outlet pressure regulation. After the damping hole is blocked, the main valve P. The cavity loses the effect of the hydraulic pressure p3, turning the main valve into a direct acting spool with a weak spring force (only the main valve balance spring), so that when the pressure at the outlet is low, the balance spring can be overcome Force and pressure reducing valve orifice shut off small ymin, so into the oil pressure p1 by ymin throttle significantly depressurized to p2, so that the pressure on the port does not come. Long holes should be made smooth. ⑦ pilot valve spring (pressure regulating spring) is wrongly installed as a soft spring, or due to spring fatigue permanent deformation or breakage and other reasons, resulting in p2 pressure is not high, can only be transferred to a certain low value, this value is much lower than Pressure regulator valve to adjust the maximum pressure. ⑧ regulator handle due to thread tension or effective depth is not enough, can not be screwed in the end so that the pressure can not be transferred to the maximum. ⑨ bad seal between the bonnet and the valve body, a serious oil spill. The cause may be O-ring leakage or damage, tighten the screw is not tightened and the valve cap surface flatness error occurs, usually around the convex, the middle concave. ⑩ main spool due to dirt, burrs stuck in a small opening position, so that the export pressure is low. Can be cleaned and deburred. (3) Symptom III: Unstable, large pressure vibration, and sometimes large noise; According to the relevant standards, J-type pressure relief valve pressure swing ± o. lMPa, JF type ± o. 3MPa, more than this standard pressure swing large, unstable. The cause of this failure phenomenon and exclude the following methods: ①J-type and JF-type valve for the pilot, pilot valve and relief valve common, so the reasons for the generation of pressure swing and the exclusion of the method may refer to the relief valve Partially carried out. ② When the pressure reducing valve is used at more than the rated flow, the oscillation of the main valve will often occur and the pressure reducing valve will not be regulated. At this moment, the pressure of the oil outlet will appear "cycle of step-up / step-down and step-down and step-down" , So be sure to choose a pressure reducing valve that fits your model's specifications. ③ L drain port by the back pressure, will also have large pressure swinging and unstable phenomenon, drain pipe should be separate back to the oil. ④ spring deformation or stiffness is not good (heat treatment is not good), resulting in large pressure fluctuations, replacement of qualified springs. (4) Symptom 4: After the setting of working pressure, the pressure of the oil outlet will increase by itself. The cause and preclusion of this failure phenomenon: In some of the pressure reducing control circuits, the outlet pressure of the pressure reducing valve is used Control of electro-hydraulic valve or external control sequence valve and other control of oil pressure size, when the electro-hydraulic valve or external control sequence valve to change or work, the valve outlet flow becomes zero, but the pressure Still need to maintain the original set pressure. In this case, because the valve outlet flow is zero, the flow through the pressure relief port has only pilot flow. As the pilot flow rarely, usually within 2L / min, so the main valve pressure relief port is basically close to the fully closed position (opening degree is very small), the pilot flow from the triangular groove or inclined cone at the outflow, if the main valve with Too loose or wear too much, then the amount of leakage increases. According to the continuity of flow theory, this part of the leakage must also flow from the main spool orifice, which flows through the orifice by the pilot flow and leakage of two parts, and the orifice area and the main valve spring cavity oil pressure Unchanged (the spring chamber oil pressure is adjusted by the pre-compression of the regulated spring), to increase the flow rate through the orifice, it inevitably causes the pressure drop in the lower part of the main valve. Therefore, when the relief valve outlet pressure is set, if the outlet flow is zero, the outlet pressure will increase due to the main spool with loose or excessive wear and tear.