Settling return flow oil in the tank

(Werdohl, July 2016)

Settling return flow oil in the tank

Diffusers reduce fluid aeration, foaming and noise generated in hydraulic reservoirs

One of the basic prerequisites for the smooth operation of hydraulic systems is the selection of a well-designed hydraulic reservoir based on the specific requirements, which does not only supply the system with sufficient pressure fluid. It also uses suitable measures (e.g. filler breathers and sufficient tank pressurisation) to prevent solids, water and air from entering the system, contaminating the oil and affecting the function of sensitive components, which quite often results in expensive downtimes and unplanned oil changes.

Another factor that should not be underestimated is surface foaming which can form through uncontrolled return flow of hydraulic oil from the return line into the tank. As an air-in-oil dispersion, this can cause a number of operating problems throughout the system. These include efficiency losses for the energy used, operating malfunctions and a reduced service life of the oil. This can lead to marked oil loss due to oil excess foaming. Cavitation in the pump also increases noise generation in the system drastically, which in extreme cases can lead to a total breakdown and therefore to a system standstill.

This is where diffusers from the SRV series from Stauff come into play: The design of the components is based on two concentric steel tubes where the perforated outlet sections are offset to each other, slowing down the oil in the return flow and settling it effectively. This can prevent the formation of oil foam and permanently reduce noise generated in hydraulic reservoirs. It also effectively prevents the raising of sedimentation and soil deposits from the bottom of smaller tanks.

Diffusers are an ideal supplement to return-line filters with threaded outlets. They are connected directly to the return line or to the filter bowl of the filter housing using BSP or NPT internal threads. The diffusers are positioned fully underneath the minimum liquid level of the reservoir, ideally with the closed surface of the outer steel tube facing the suction end of the pump.

The extensive Stauff product range offers diffusers for a maximum operating pressure up to 20 bar (in the return line), covering the complete spectrum of required flow rates up to 950 litres per minute.

Image 1:

Steel diffusers with perforated outlet areas
(Courtesy of Walter Stauffenberg GmbH & Co. KG)

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Image 2:

Perfect combination: Return-line filter housing with diffuser
(Courtesy of Walter Stauffenberg GmbH & Co. KG)

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Background Information

For more than 50 years now, the STAUFF Group with headquarters in Werdohl (Germany) has been successful in the development, manufacturing and distribution of pipework equipment and hydraulic components for mechanical and plant engineering as well as for service and industrial maintenance. The overall product range currently includes about 33,000 standard products as well as numerous special and system solutions according to customer requirements or based on own developments.

Wholly-owned manufacturing, sales and service facilities with more than 1,150 employees in 18 countries and a tight network of authorised distributors and representatives in all major industrial regions of the world ensure high presence and service paired with a maximum of availability.

In April 2015, VOSWINKEL was acquired and became a member of the STAUFF Group. With two sites located in Meinerzhagen (Germany) and 230 employees, VOSWINKEL is considered to be one of the world's five largest producers of quick release couplings for hydraulic systems. The long-established company also develops and produces a comprehensive range of hydraulic hose fittings – particularly for high-pressure applications – as well as custom-designed piping, primarily for construction and agricultural machinery as well as for commercial vehicles.

In 2015, the companies of the STAUFF Group have generated external sales revenue totalling EUR 230 Mio.

Press Contact

Mr Boris Mette
Head of Marketing Communications
Tel.: +49 (0) 2392 / 916-154
Fax: +49 (0) 2392 / 916-270154