China Shandong Yizhi Machinery and Equipment Co., Limited Company Cases

Hydraulic pumps may produce abnormal noises during use. What are the causes and main reasons for the abnormal noises? The following hydraulic maintenance manufacturers will explain them in detail for you. Usually, the main cause of abnormal noise in hydraulic pumps is suction phenomenon. During the operation of the hydraulic pump, air is mixed into the oil, which leads to the formation of air pockets in the high-pressure area, resulting in suction noise and noise, mainly due to the following reasons. Hydraulic maintenance Hydraulic pumps may produce abnormal noises during use. What are the causes and main reasons for the abnormal noises? The following hydraulic maintenance manufacturers will explain them in detail for you. Usually, the main cause of abnormal noise in hydraulic pumps is suction phenomenon. During the operation of the hydraulic pump, air is mixed into the oil, which leads to the formation of air pockets in the high-pressure area, resulting in suction noise and noise, mainly due to the following reasons. Hydraulic maintenance

The use and maintenance methods of hydraulic pumps   1. Oil supply method of hydraulic pump There are two types of direct axis inclined disc piston pumps: pressure oil supply type and self suction type. Pressure oil supply hydraulic pumps mostly use oil tanks with air pressure, and some hydraulic pumps themselves have oil replenishment pumps to supply pressure oil to the hydraulic pump inlet. The self suction of the self suction hydraulic pump is very strong. The hydraulic oil tank for pneumatic oil supply should wait for the hydraulic tank to reach the required air pressure before adjusting the operation of the machinery. When there is a lack of air pressure in the hydraulic oil tank, it will act as a machine and cause a pulling phenomenon between the hydraulic pump and the slider, resulting in abnormal wear of the return plate and pressure plate inside the pump. Select a plunger pump with a supplementary oil pump for oil supply. After use, the operator needs to check the plunger pump 1-2 times a day to check if the hydraulic pump is operating normally. If it is found that the speed of the hydraulic cylinder has decreased or the car is stuck, the oil replenishment pump should be checked for collapse, and whether there is any phenomenon at the edge of the impeller and whether the clearance of the internal gear pump is too large. The oil level in the hydraulic oil tank of the self-priming plunger pump must not be lower than the lower limit of the oil gauge, and the quantity of hydraulic oil must be consistently met. The higher the cleanliness of hydraulic oil, the longer the service life of hydraulic pumps. 2. Bearings for hydraulic pumps The main component of a plunger pump is the bearing. Assuming that the bearing has clearance, it cannot provide normal clearance for the three pairs of friction pairs in the hydraulic pump, and it will also damage the thickness of the static hydraulic support oil film of each friction pair, reducing the service life of the plunger pump bearing. According to the information provided by the hydraulic pump manufacturer, the uniform service life of the bearing is 10000 hours. The clearance of the disassembled bearing cannot be checked without an inspection instrument, and only visual inspection can be used. If scratches or discoloration are found on the roller surface.   Let me explain to you the 7 mistakes in hydraulic maintenance It is difficult to avoid damage to hydraulic oil pumps during long-term operation, and the reasons and maintenance methods for each damage are different. If the hydraulic pump repair operator, Mr. Cheng, lacks rich and diverse work experience and professional skills, then secondary damage will occur. Wuhan Hydraulic Repair will explain to you the reasons for the damage of the 7th hydraulic oil pump and the appropriate maintenance methods. 1： Because the piston rod and cylinder liner are related to transitional cooperation, when installing the cylinder liner, the piston rod should be deformed by heat first. Therefore, some maintenance workers will immediately heat the piston rod on fire to exceed the actual effect of encountering heat. That approach is very incorrect because the thickness of the piston rod is uneven in all directions, resulting in different levels of thermal expansion and contraction. Heating with fire can cause uneven heating of the piston rod, which can easily cause deformation; The surface of the piston rod will also adhere carbon ash, reducing the service life of the piston rod. 2： In hydraulic maintenance, many positions of the anchor bolts have specific torque requirements, such as the gearbox, cylinder head, wheel rim, crankshaft, and front axle assembly. The tightening torque is often specified in the instructions and should not be changed arbitrarily. If incorrect anchor bolts or torque are applied, it may cause a component of the hydraulic oil pump to loosen, leading to damage. 3： When the hydraulic oil pump is overloaded during operation, or when the water flow in the storage tank is insufficient or the heat pipe is not well cooled, in order to quickly cool down after working for a long time, immediately add cold water to the storage tank. This behavior is incorrect and may lead to cylinder head and engine block explosions. People should add coolant to the hydraulic oil pump after cooling to ensure the actual heat dissipation effect of the heat pipe.

Common problems encountered in hydraulic pump repair The common problems encountered in hydraulic pump repair include abnormal pressure in the hydraulic system, inability to increase or decrease pressure. Pressure is one of the two basic parameters of the hydraulic system, which largely determines the performance of the hydraulic system. This problem manifests as: when regulating the pressure of the hydraulic system, there may be a failure to establish the system pressure, a lack of pressure, no pressure at all, perhaps the pressure cannot be adjusted down, or it may rise and then fall down again, and the regulated pressure is unstable and fluctuates greatly. 1. The impact of abnormal pressure ① Execution components (such as hydraulic cylinders, hydraulic motors) do not act or, although they act, stop operating with a load or are powerless, unable to overcome the load and do work; ③ Some valves that rely on pressure control cannot operate, such as hydraulic directional valves, hydraulic control check valves, plug-in valves, pressure relays, etc. Hydraulic maintenance also leads to the hydraulic system not functioning properly: ⑤ Malfunctions, including safety accidents, occur due to uncontrolled stress regulation, Overheating of the motor is a common problem that occurs during the operation of high-temperature oil pumps. The specific analysis and testing are as follows: 1. Does the usage range (flow rate, head) exceed the design requirements of the high-temperature oil pump? Select the appropriate motor according to the series spectrum 2. Does the medium density exceed the configuration of the high-temperature oil pump motor? Configure a suitable motor for the Dajiang high-temperature oil pump 3. Is the packing gland pressed too tightly or the mechanical seal spring adjusted too tightly? Adjust the compression amount of the spring for the pressure cover or mechanical seal again 4. The assembly quality of the gear pump is poor, and there are friction areas or the motor and pump shaft are not concentric during hydraulic maintenance   During hydraulic maintenance, identify the cause of the malfunction from the following three points and make improvements to the system: (1) Check the internal leakage of the boom cylinder. A simple method for Z is to raise the boom and see if there is any noticeable free descent. If the drop is obvious, disassemble the oil cylinder for inspection. If the sealing ring is worn, it should be replaced. (2) Check the control valve. Firstly, clean the safety valve and check if the valve core is worn. If worn, replace it. If there is still no change after the installation of the safety valve, the hydraulic maintenance should check the wear of the control valve core again. The clearance limit is generally 0.06mm, and if the wear is severe, it should be replaced. (3) Measure the pressure of the hydraulic pump. If the pressure is too low, adjust it. If the pressure still cannot be adjusted, it indicates that the hydraulic pump is severely worn.

    Do you know the installation taboos for hydraulic maintenance?   1. Avoid using hydraulic pumps with weak foundations. 2. If the coaxiality between the hydraulic pump shaft and the prime mover shaft exceeds the tolerance, the operation of the hydraulic pump should be stopped. 3. It is forbidden to use a rigid connection between the hydraulic pump transmission shaft and the electric motor transmission shaft. Generally, an elastic coupling should be used for connection. 4. Avoid using the front cantilever of a regular electric transport machine to support the hydraulic pump. 5. Avoid using hydraulic pump support brackets (bent plates) with poor rigidity. 6. Avoid placing hydraulic pump devices with painted casings below the oil level in the tank. The part of the inclined plate in contact has an oil chamber, which is connected to the working chamber in the cylinder body through a small hole in the middle of the plunger. After hydraulic maintenance, a layer of oil film is formed between the contact surface of the sliding shoe and the inclined plate, which plays a role in static pressure support, greatly reducing the force of the sliding shoe on the plate and thus reducing wear. A single acting vane pump has one oil discharge port and one oil suction port. The rotor rotates once, and the volume between each two blades absorbs and discharges oil once. If the eccentricity between the rotor and stator is made variable in structure, it is a variable vane pump. The single acting vane pump is suitable for low-pressure and high flow applications. The double acting vane pump has a rotor that moves back and forth twice in the groove every revolution, and hydraulic maintenance completes two oil suction and discharge operations. Due to its two oil suction zones and two oil discharge zones, symmetrically distributed relative to the center of the rotor, the forces acting on the rotor are balanced and the flow rate is relatively uniform.

  Several yearts  ago,  we   manufactured  a  test bench  for  a  Iranian customer whose  request  is  high.  This  test bench is  with  famous brand  driving  motor  and  frequency converter.    Below is  the details of  his  test bench.       Hydraulic Pump test bench       Functional requirements: Available to test hydraulic pump (open, closed, double open pump), high speed motor to be tested according to working-state test and low-speed hydraulic motor is tested in simple way.   The computer on the test bench acquires the test data of hydraulic pump and the hydraulic motor and record them and then form displaying curves and print test report.       II. , Test Items:   1, Displacement test: no-load pressure test, displacement test   2, Test of volume efficiency: the volume efficiency under rated operating conditions,   3. Overload test: maximum displacement of hydraulic pump or motor (high speed), nominal speed, running for 1 minutes or less under rated pressure of 110% or under the maximum pressure     4. External Leakage test: in the test above, check the leakage of the sealing parts.     III. Function and parameters of the test bench 1. driving mode: by electric motor, 160kw+22KW+2.2KW+0.75KW+   2, speed adjusting mode: frequency converter control 0-1500r/min.     3, loading mode: two-way loading, through manual relief valve, 42 Mpa, Tandem pumps can be tested.     4. displaying mode: rotation speed, flow, and the temperature are showed in digital .meter. Pressure is displayed by mechanical meter   Oil supply from test bench to pump needing test:: both self priming ,and in forced way   5. what can be tested? the test bench mainly test open hydraulic pumps, tandem open pumps, closed pumps, and high-speed hydraulic motors. , and auxiliary test hydraulic valve and low speed motor ,etc. 6 The test bench is able to test both clockwise rotation and counterclockwise rotation pumps   7. the test bench can generate and print test report.     8. the test bench is with filter equipment for recovery of leakage oil.   9,oil tank volume: 850L   10. oil in and oil out are filtered with alarm function Main configuration details No. Name Model or Specification Qty 1   Siemens Electric motor 160 kW 1 2 Siemens Electric motor 22kw   1 3 Siemens Electric motor 2.2 kw   1 4   ABB Frequency converter 160KW 1   5   Torque tester   ±1000/n.m   2       Power Control cabinet     1 set 6 Oil filtering equipment , 0.75 KW 1 7 Relief vale Cartridge type and plate type 10 8 One-way valve Cartridge type and plate type 6 9 Hydraulic manifold block   4 10 Oil-return filter 10u 2 11 Oil absorbing filter   1 12 Air filter   1 13     1 14       15 Oil tank and hoses   1 set 16 Flow sensors   3sets 17 Digital meters   6 18       19   Hydraulic Pumps     2 pcs   20 Proportional controller   2 21 Ball Valve   2 22 Hydraulic hose   1 set 23 Wind cooler 400L 1 unit 24 Touch screen computer   1 25 Printer HP brand 1   26       27 hydraulic motor A2FE160 1   28 ammeter     1 29 voltmeter     1   30   The connecting round discs and couplings for pumps and motors, can be made in the buyer's local processing factory by giving them drawings.     31       The assisting pump for testing motors is prepared by the buyer.   A constant-displacement pump is recommended as the assisting pump.