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How to determine whether the oil filter of the hydraulic press is blocked

Views: 1 Author: Site Editor Publish Time: 2025-08-25 Origin: Site

To determine whether the oil filter of the oil press is blocked, it is necessary to combine multi-dimensional means such as pressure monitoring, flow observation, and physical inspection. It is necessary to identify hidden blockage through equipment operation data, and to confirm the degree of blockage through disassembly inspection. The following are the specific methods, sorting from 'convenience' from easy to difficult, covering daily inspections and professional inspection scenarios:

1. Intuitive judgment through the operating status of the hydraulic press (no disassembly required, daily inspection)

A blockage of the oil filter will cause the hydraulic system to 'poor oil supply' and thus cause a series of abnormal manifestations. It can be preliminarily judged by the following phenomena:

1. Observe system pressure abnormalities

When the oil filter is blocked, the resistance of the oil through the filter element increases, which will increase the pressure difference between the inlet and outlet of the oil filter. This is the most core basis for judgment:

Oil filter with differential pressure transmitter (mainstream configuration):
The oil filter comes with a pressure sensor or mechanical message transmitter. When the pressure difference reaches the set value (usually 0.3~0.5MPa, please refer to the equipment manual for details), the indicator light will be on (electrical control) or the mechanical alarm rod will pop up (manual reset), which will directly indicate blockage and the filter element needs to be replaced immediately.
Oil filter without pressure differential transmitter:
Use a pressure gauge to measure the pressures of the oil filter'inlet' and 'outlet' respectively (the pressure measuring ports must be reserved at the inlet and outlet in advance), and calculate the pressure difference:

Normal pressure difference: generally ≤0.1MPa (low resistance to cleaning filter element);
Blockage warning: Pressure difference > 0.2MPa (the resistance increases significantly and the filter element begins to be blocked);
Severe blockage: pressure difference > 0.3MPa (the oil flow is blocked and urgently needs to be treated).

2. Observe the abnormal movement of the actuator

The oil filter is blocked and the oil supply flow is insufficient, and the actuators such as the oil cylinder, motor, etc. of the hydraulic press will have 'insufficient power' or 'slow action', which is specifically manifested as:

The lifting speed of the oil cylinder becomes significantly slower (if it is normal to rise to the position in 10 seconds, it takes more than 20 seconds after blockage);
The pressure drops quickly when maintaining pressure (due to insufficient flow, the pump cannot replenish oil in time);
The movement is stuck and abnormal noise (the oil flow is not smooth, and the system is 'empty' or 'sleeping oil').

3. Observe the abnormal increase in oil temperature

The blocked filter element will hinder the flow of oil. The oil generates additional heat at the filter element due to the 'throttling effect'. At the same time, the pump will consume more power to overcome resistance, which will eventually lead to an abnormal increase in the hydraulic oil temperature:

Normal working oil temperature: generally 30~55℃;
Oil temperature during blockage: It may exceed 60℃, and the outer wall of the oil tank becomes hot and the viscosity of the hydraulic oil decreases (touching the oil tank with your hands makes it feel hot).

2. Assist in determining the oil condition (check the root cause of blockage and avoid secondary blockage)

The essence of the oil filter blockage is that 'there are too many impurities in the oil, which exceeds the filter element's filtering capacity'. It can be further confirmed by the appearance and pollution of the oil:

1. Observe the appearance of the oil

Take a small amount of hydraulic oil and place it in a transparent container. If the oil is turbid, black, and has obvious precipitates or flocs, it means that the oil is seriously contaminated and the oil filter is likely to be blocked (the filter element intercepts a large amount of impurities);
Compare new oil: If the oil color becomes significantly darker (such as from light yellow to dark brown), and the transparency decreases, the blockage situation needs to be judged based on the pressure data.

2. Detection of oil contamination (professional scenarios)

Use an oil contamination detector (such as a particle counter) to detect the number of impurities in the oil (graded according to ISO 4406 standard):

If the pollution level exceeds the equipment requirements (such as the hydraulic press usually requires ISO 18/15/12, that is, 25~50μm particles ≤1000 pieces/mL), it means that the oil filter can no longer be effectively filtered, and may have been blocked or the filter element fails;

If there is no detector, you can remove the oil filter and rinse the filter element with a clean solvent (such as kerosene) to observe whether there are a large amount of metal debris, dust, rubber particles and other impurities in the rinse liquid - the more impurities, the more serious the blockage.

3. Disassemble the oil filter and check directly (final confirmation, and the machine needs to be shut down)

If the above method is still unsure, or the degree of blockage needs to be confirmed, the machine needs to be shut down and disassembled the oil filter (pressure relief must be required before operation to avoid oil spraying):

1. Disassembly steps (taking the tube/plate oil filter as an example)

Turn off the power supply of the oil press, open the system pressure relief valve, and release the pressure from the inlet and outlet of the oil filter (ensure that the pressure gauge reads 0);
Remove the end cover or flange bolts of the oil filter and remove the filter element (be careful to avoid impurities falling into the oil tank);
Blow air from the 'outlet side' to the 'inlet side' with clean compressed air (pressure ≤ 0.2MPa) from the filter element to observe whether there is any air flow or impurities blow out.

2. Filter element status judgment criteria

Suggestions on handling	filter element state	clogging
No obvious impurities on the surface, smooth blowing	Not blocked (normal)	You can continue to use after cleaning the surface dust
A small amount of impurities adhered to the surface, and there is slight resistance to blowing	Mild blockage	After rinsing with kerosene, if the pressure difference returns to normal, it can be reused
The surface is covered with thick impurity layers, the blowing air is not smooth, and the filter element is deformed	Severely blocked	Replace the filter element immediately (not reusable)
Filter element breaks and holes appear	Failure (replace urgently)	Replace the filter element and check for impurities in the fuel tank

4. Precautions (avoid misjudgment or damage to the equipment)

Differentiate between 'blocking' and 'other faults':
slow actuation of the actuator and high oil temperature may also be problems such as 'pump wear' and 'overflow valve stagnation'. These faults need to be eliminated first (such as checking whether the outlet pressure of the pump is normal and whether the overflow valve is relieved), and then focus on the oil filter.
Keep it clean during disassembly:
During the process of disassembly, all tools and containers must be clean to avoid introducing new impurities (otherwise it may cause secondary failures such as valve group stuck, pump wear, etc.).
Regularly replace the filter element:
Even if there is no clogging alarm, the filter element must be replaced regularly according to the requirements of the equipment manual (usually every 3 to 6 months, or 1,000 hours of operation) - After the filter element is used for a long time, the filtration accuracy will decrease, and even if it is not completely clogged, it may lead to oil contamination.

Through the above methods, we can comprehensively and accurately determine whether the oil filter of the oil press is blocked. During daily inspections, it is recommended to pay priority to pay attention to the pressure difference alarm signal and the operating status of the actuator, which can not only detect blockages in a timely manner, but also reduce the frequency of shutdown inspections to ensure stable operation of the equipment.