How Do You Test A Hydraulic Cylinder

Hydraulic cylinder test is necessary before application to make sure if it is qualified. All of our produced hydraulic cylinder will be 100% tested before shipping. Test method and operating instructions are as follows.

Trial operation of hydraulic cylinder.

The hydraulic cylinders at each station are in place, prepare the “Hydraulic Cylinder Factory Test Recording Table”, manually record the hydraulic cylinder code, connect the tested hydraulic cylinder (two hydraulic cylinders can be tested at the same time), open the ball valve, start the oil pump, and check each For key parts, operate the electro-hydraulic reversing valve to change direction, and the hydraulic cylinder will start pre-operation.

Starting pressure.

Pre-connect the pressure gauge to the working chamber to test, manually visually inspect the digital display electronic pressure gauge, operate the electro-hydraulic reversing valve and adjust the control handle of the relief valve slowly until the hydraulic cylinder starts to start. Then observe and record the pressure value on the table. Run for 2-3 cycles for exhaust, and the number of cycles is adjustable. It is mainly to observe whether the cylinder has long stroke crawling, severe jitter, and whether the short stroke hydraulic cylinder is stuck in parallel operation and other abnormal conditions.

Pressure test.

The pressure test also includes a static pressure holding test. After the tested hydraulic cylinder reaches the end of its stroke, the medium and high pressure are automatically switched, and the ultra-high pressure pump automatically continues to pressurize the working chamber. The pressure is smoothly and effectively supplied through the pre-adjusted relief valve. At this time, keep the electro-hydraulic valve at the reverse position, and let the high-pressure plunger pump continue to pressurize for 1-2 minutes (the pressure is 1.25 or 1.5 times the working pressure). Due to the selection of high-performance hydraulic locks, hydraulic cylinders can also be used. After the pressure in the test chamber rises to a certain value, the high-pressure system is also unloaded, and the pressure is maintained by the hydraulic lock. The time is adjustable according to the product itself.

telescopic hydraulic cylinder pressure test
hydraulic cylinder test

Leakage test.

External leakage

During the first, second, and third tests, check the welding points on the outside of the hydraulic cylinder, the piston rod and the guide sleeve, the guide sleeve and the cylinder liner, the joints and flange connections on the cylinder block, etc. Whether there is leakage or leakage at the seal.

Internal leakage

The test method focuses on the third item (pressure holding test in the pressure test). It must be combined with the pressure test, that is, after the continuous pressure stops, the high-pressure system is unloaded and the hydraulic oil return returns to the tank directly. The hydraulic control check valve automatically locks the oil circuit, and the hydraulic cylinder oil cavity maintains pressure. After confirming that there is no leakage in the system oil circuit of the test bench or the natural leakage value of the system, check the pressure drop per unit time for indirect feedback. Eligibility should be based on the actual situation of the site to formulate standards.

Hydraulic cylinder buffer test.

Observe the cushioning effect when the hydraulic cylinder reaches the two ends, adjust the cushion throttle rod of the cylinder (if the product does not have this adjustment, just omit it), watch the buffer speed change, manually monitor the impact of the piston and the cylinder end cover, and analyze whether the product is needed adjust the rationale to pass.

Hydraulic stroke detection test.

During the above test of the hydraulic cylinder on the test bench, the effective extension length (longest and shortest) of the piston rod can be measured manually or mechanically during the static pressure holding period. At this time, the results are recorded and compared with the original design data. , To find out whether the stroke of the hydraulic cylinder meets the regulations, and at the same time, the speed of the stroke of the hydraulic cylinder under a certain flow rate can be calculated, and the maximum accuracy per unit time can reach 1mm/sec.

Drain the oil after the test is over.

After completing the hydraulic cylinder test, the electrical control system will check whether the cylinder is qualified and save the record on the base of the internally stored test data and the manually recorded observation data.

There is a special “Cylinder Test Qualified” button. This button is mainly for whether the leakage in the cylinder is qualified. And setting, press this switch to automatically display whether the product is qualified or not.

Qualified products will have a corresponding green light to indicate. Unqualified products will also have corresponding red warning lights or buzzer to give an alarm, after confirming the hydraulic cylinder is qualified. Manually record the model, number, quantity and sequence, and the unqualified product manually compares the test results of each link, makes necessary processing, and the operator corrects or retests on base of the experience and the data obtained.

After the test, draining and resetting the hydraulic cylinder is necessary regardless of whether it is qualified or not. After confirming that there is no high pressure after releasing pressure from the inner cavity of the hydraulic cylinder, manually switch the hydraulic cylinder oil discharge control button. At this time, no matter where the piston rod of the tested hydraulic cylinder is, it will be moved back and forth several times without load.

For example, the piston rod is extended, the gas enters the rod cavity of the hydraulic cylinder under the action of the reversing valve, the rodless cavity interface of the hydraulic cylinder has been directly connected to the oil return pipe, and the other end of the oil return pipe is connected to the small oil collecting tank. The piston rod is forced to retract, the hydraulic oil in the rodless cavity of the hydraulic cylinder is discharged from the interface under the action of the piston movement, and flows back into the oil collecting tank along the oil return line. After the piston rod runs to the end, press the other operating button and repeat the above p After confirming that the hydraulic oil in the cylinder body is basically drained, the piston rod is reduced to the shortest size, the line is manually taken off the assembly line, and the qualified product is packaged, end the hydraulic cylinder test.

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