Hydraulic Oil Filter Element 938291Q 938293Q 938294Q 938290Q 938292Q 938269Q 938273Q

Pre-filtered oil: The oil about to enter the hydraulic system is preliminarily filtered to capture larger particulate contaminants, such as assembly residues, seal fragments, and dust brought in by air.

Enhance system reliability: By protecting the hydraulic pump – the heart of the entire system, ensure the stable operation of the entire hydraulic system and reduce downtime caused by pump failures.

Ii. Working Principle
As an oil suction filter element, 938291Q mainly operates on the principle of deep filtration and is equipped with a protection design to prevent the pump from being sucked empty.

Suction filtration: When the hydraulic pump is in operation, a negative pressure (vacuum degree) is generated at the oil suction port. Under the effect of atmospheric pressure, the oil in the oil tank passes through the filter medium of the filter element. Contaminants are retained on the outer surface of the filter element or deeply accumulated inside the filter material. Clean oil then enters the interior of the filter element and flows towards the oil suction port of the pump.

Filtration method: Oil-absorbing filter elements typically use filter materials with high porosity and low flow resistance (such as metal mesh or special fibers), mainly for deep filtration, relying on the complex fiber structure to adsorb and retain particles.

Bypass valve protection

The bypass valve of the oil suction filter is usually integrated into the filter element (which is different from the return oil filter).

Working principle: When the filter element is clogged by contaminants or the oil viscosity is too high (such as during cold start), causing the pressure difference between the inlet and outlet to increase to the set value (for example, 0.1-0.2 bar), in order to prevent the pump from insufficient oil suction and causing cavitation and damage, the bypass valve integrated inside the filter element will be pushed open, allowing the oil to enter the pump port directly without filtration. This is a necessary measure to protect the pump.

Once the bypass valve is opened, the system loses its filtration protection. The filter element should be replaced as soon as possible when conditions permit.

Iii. Operation and Installation
Installation steps (for the oil suction filter element immersed in the oil tank) :

Safety and Preparation

Completely cut off the power supply of the equipment and ensure that the hydraulic system does not start accidentally.

Clean the top of the fuel tank and the surrounding area to prevent contaminants from falling into the tank.

Open the cleaning cover or flange on the fuel tank.

Replace the filter element

Carefully remove the old filter element assembly vertically from the fuel tank. Be careful not to stir the sediment at the bottom of the fuel tank.

Thoroughly clean the sealing area on the old filter element installation seat (connecting flange).

Check whether the O-rings or gaskets of the new filter element (938291Q) are intact and elastic, and apply a small amount of clean hydraulic oil for lubrication.

Place the new filter element vertically and steadily into the oil tank, ensuring it is aligned with the installation base. Then, evenly tighten the screws of the connecting flange to guarantee a reliable seal.

Important: Ensure that the bottom of the filter element is kept at a sufficient distance from the bottom of the fuel tank (usually with a recommended value) to prevent sediment at the bottom of the fuel tank from being sucked in.

Completion and Inspection

Install and tighten the fuel tank cap.

Before starting the system, if possible, it is best to pre-oil the pump through the oil drain port or by tapping the pump.

Start the system and run it for a period of time under no-load or low pressure conditions to check for any abnormal noises (cavitation sounds) or leaks.

Iv. Usage Scenarios
The 938291Q oil suction filter element is widely used in the hydraulic systems of various industrial equipment and mobile machinery, especially in those situations with high requirements for pump protection:

Injection molding machine

Machine tool (hydraulic station

Hydraulic oil tanks for construction machinery (such as excavators and loaders)

Casting machinery

Pressure machinery

Ship hydraulic system

V. Product Attributes/Technical Specifications
Attribute description

The filtration accuracy is usually 100μm or 150μm (this is the typical accuracy range for oil absorption filtration, and the specific range needs to be confirmed with the filter element label).
The filter medium is usually a metal mesh or special coarse-precision fibers
The structural features include a built-in bypass valve, a support spring at the bottom, and a seal at the top
Sealing parts: Nitrile rubber (NBR) O-rings or gaskets
The installation method is immersion type, which is installed inside the fuel tank through the top flange
Vi. List of Series Models
“938291Q” is a specific part number. Oil-absorbing filter element models of the same series or similar functions are usually distinguished by changing the precision, length and interface.

Common alternative or similar series models:

Different levels of precision

938290Q: It may have a precision of 125μm.

938292Q: It may have a precision of 200μm.

(Note: The precision code has a weak correlation with numbers. Please refer to the precision marked on the physical product label.)

Different sizes/flow rates

There is a complete series of oil suction filter elements, with numbers such as 9382XXQ (XX represents different digits), corresponding to different lengths, flow rates and interface sizes, to meet the flow requirements of oil tanks and pumps of different sizes. For example, there might be 938293Q, 938294Q, etc.

Alternative model

Other brands (such as HYDAC, MANN, Donaldson) also have oil-absorbing filter elements of corresponding sizes and precision, but their part numbers are completely different.

938253Q 938257Q 938261Q 938265Q 938269Q 938273Q