Breather Filters for Construction Equipment

Selection by Reference Number and System Application

Identification is based on the reference number of the installed breather filter or on the technical assignment to the respective tank, gearbox or housing system. In spare parts operations, this allocation is critical, as thread types, designs and filter media vary significantly depending on the application.

Reference numbers are used across manufacturers, including HIFI FILTER, Donaldson, MANN+HUMMEL, ARGO-HYTOS, Filtration Group, Elsaesser and others.

Accurate identification prevents incorrect orders and avoids installation issues during maintenance and service operations.

Function in Tank, Gearbox and Housing Systems

Breather filters allow controlled air exchange between the system interior and the surrounding environment. This pressure equalization is required when overpressure or vacuum conditions occur due to temperature changes, fluid level variations or operational movement.

At the same time, they limit the ingress of dust, particles and moisture into hydraulic tanks, oil reservoirs, gear housings and other closed systems. This supports fluid cleanliness and reduces contamination-related wear.

In contrast to air filter elements, filtration does not take place in the engine intake system, but at the ventilation point of closed systems.

Typical Applications

• Hydraulic tanks: pressure equalization and reduction of moisture ingress during level and temperature changes
• Gear housings: ventilation under thermal expansion and fluctuating load conditions
• Oil reservoirs and storage tanks: limitation of particle and water ingress from the environment
• Closed housings and aggregates: controlled air exchange under varying operating conditions and outdoor exposure

Breather filters are used in construction equipment, agricultural machinery and industrial applications, particularly where tanks and housings “breathe” during operation and must be protected against environmental contamination.

Filter Types and Media

• Standard breather filters: filtration of incoming and outgoing air under general dust conditions
• Desiccant breathers: additional reduction of moisture ingress, typically using drying media
• Special designs: depending on system requirements and operating conditions
• Breather housings and assemblies: with integrated or replaceable filter media depending on design

Filter media selection depends on dust load, humidity, required filtration efficiency and the air exchange characteristics of the system.

Connection Sizes, Designs and Installation

In addition to the reference number, thread size, nominal diameter, installation height and housing design are critical selection parameters. Even minor deviations can lead to installation issues or improper system performance.

For desiccant breathers, capacity must be matched to the moisture exposure of the system.

System Context within Filtration Technology

Breather filters are part of construction equipment air filters and are integrated within the broader category of filters for construction equipment.

They operate alongside air filter elements, cabin air filters and air filter accessories, but serve a distinct function in pressure equalization and contamination control of closed systems.

For fluid filtration within hydraulic circuits, refer to hydraulic filters.

Maintenance and Replacement

Breather filters are maintenance-relevant components. Service intervals depend on dust exposure, humidity, air exchange rate and operating conditions.

A saturated or unsuitable breather filter reduces air exchange efficiency and can no longer effectively prevent contamination. In desiccant versions, moisture absorption capacity decreases as saturation increases.

Verification Before Ordering

Before ordering, reference number, system application, connection size and filter type must be verified.

Check Before Ordering

• Reference number of the installed filter
• System application (tank, gearbox, housing)
• Connection size / thread
• Design and installation height
• Standard, desiccant or special version

Technical Support

Selection is based on correct technical assignment to the existing system and the specific operating conditions of the machine or installation.