Compressed-air filters

How does a hydraulic pressure filter work?

Pressure filters play a central role in the safe operation of hydraulic systems, as they ensure the longevity and reliability of the systems.

Hydraulic pressure filters are installed downstream of the system pump and thus provide direct component protection, for example of servo valves and other sensitive system components. In addition, they are used to achieve and maintain the desired oil cleanliness in the hydraulic system. Without pressure filters, dirt particles, abrasion and other impurities in the oil cause the components to wear prematurely, which jeopardizes operational reliability and reduces the performance of the entire system.

The design of pressure filters and all other system components must always be tailored to the respective application and its requirements. When selecting suitable filter components, a number of factors must be considered. These include the maximum operating pressure, differential pressure loads, volume flow, filter rating, connection size, temperature range and the fluid used.

How is a hydraulic pressure filter constructed?

Pressure filters consist of a filter housing, filter element and additional components.

The filter element is the core component and removes dirt particles from the hydraulic fluid.

The maintenance-friendly housing is made of aluminum or steel and can withstand the operating pressure over the long term.

A bypass valve protects the filter element at high pressure differentials and when the filter element reaches saturation point, ensuring that the system continues to be supplied with oil.

A clogging indicator (optical or electrical) indicates when the filter element needs to be changed.

As soon as the dirt holding capacity of the filter element installed in the pressure filter is reached, the pressure conditions in the filter housing increase. As a result, the bypass valve opens at a defined pressure to continue supplying the system with hydraulic fluid and to prevent damage to the system components. The clogging indicator plays a crucial role in this context, since a timely filter change is essential for operational reliability. When the bypass valve is open, no filtration takes place through the filter element, so dirt particles are carried further in the hydraulic system.

What are the special features of hydraulic pressure filters?

In hydraulic systems with particularly critical components, we recommend using only pressure filters without bypass valves. These filters must be equipped with a filter element that can withstand even higher differential pressure loads without being damaged. In such systems, the clogging indicator is of particular importance.

What types of hydraulic pressure filters are there?

In the field of hydraulics, a distinction is generally made between four pressure ranges:

• Low-pressure filters up to an operating pressure of approx. 100 bar
• Medium-pressure filters from 100 to 200 bar operating pressure
• High-pressure filters from 200 to approx. 500 bar operating pressure
• Ultra-high pressure filters with operating pressures above 500 bar

Our product range of pressure filters is diverse and covers all areas of application. We offer you the right pressure filter for your requirements in a wide variety of designs.

Pressure filter in modular system from Elsässer Filter-Technik

In addition to the various pressure filter series, which we would be happy to design for you and deliver ready for installation and use, we also have a modular system ready for you.

The advantage of our modular system:

We keep selected filter housings in stock, combined with the desired filter element and maintenance switch, which usually allows us to ship your order on the same day. Our modular system includes the following components:

1. filter housing (often with bypass valve)

2. suitable filter element (in the required filter fineness)

3. Optional maintenance switch (optical or electrical)

We usually have pressure filter housings with bypass valves in stock. You select the appropriate filter housing and filter element and complete the pressure filter after delivery. This means that you can put your new pressure filter into operation in just a few simple steps.

This results in a multitude of possible combinations for your individual requirements. We would be happy to configure the pressure filter according to your specifications.