Hydraulic filters

The viscometer assembly is placed in the constant temperature column compartment of the chromatograph between the column outlet and the refractometer. A combination of two Waters Associates M-45 hydraulic filters in series with a capillary tubing coil (length 10 ft., I.D. 0.01 in.) is used to dampen the line pressure fluctuations caused by the pump. With the above pressure damping modifications the overall system noise was reduced to less than 1 millibar at 1.0 ml/min flow rate in tetrahydrofuran (THF) for a set of six p-Styragel columns 10 ,... 

The noise due to the reciprocating action of the dual-headed pump in the 150C ALC/GPC has a constant frequency pattern and can be reduced by hydraulic filters as shown in Figure 3. A 60% reduction in the peak-to-peak noise is achieved by using a Mark II dampener (Laboratory Data Control, River Beach, Florida), while the M-45 filters under same conditions have reduced the noise by 90%. 

Figure 3. Effect of the commercial hydraulic filters on the baseline noise of the viscometer trace (Mobile Phase THF, Flow Rate 0.5 ml/min. Temperature 30 C)...

Industrial hydraulics filter elements get make over... 

Etonaldson Company has redesigned its Triboguard line of industrial hydraulics filter elements in order to increase dirt capacity and low er pressure drop. 

TheTriboguaid Mneof iiiJurtrial hydraulics filter Elmnti from Donaldson. 

Zone 3 comprises granular soils (dgs > 2.0 mm), and the hydraulic filter efficiency can often be easily maintained using a geotextile which meets the retention requirements for Zone 2 soils. 

A quasi-steady calculation of the cam-follower contact learns that film thicknesses of the order of 1 pm and even smaller can be expected. This necessitates a filter which will arrest all particles larger than 3/4 of the minimum film thickness. Absolute submicron filters do not permit a sufficiently large fluid flow in main stream applications, so it was decided to put it in a bypass, see Fig.4. The main stream contains a large hydraulic filter 4. From there the stream is divided over three parallel flows, i.e. the double hydrostatic bearing 2, the absolute filter 3 and the jet 1. Eventually all fluid will arrive... 

Change a hydraulic filter and other system components... 

Change the hydraulic filter (could be the return or pressure filler). 

Never touch a hydraulic filter with your hand during installation. By touching the filter you will introduce contamination to the hydraulic system. 

Abrasive particles contained in a hydraulic oil system, if unfiltered, enter the system, they would damage sensitive components like pumps, valves, and motors. The nonwoven hydraulic filter is designed to remove these parficles from the oU flow to prevent hydraulic system failure from any premature component wear. Nonwoven filters either contain novel materials, such as magnetic polymer fibres, or have special designed structures (eg, multilayer composite filter medium for serial filtration ) that are employed to filter the solid abrasive particulates, soft particles, corrosive chemical particles, and some microorganisms. 

Aluminium-free hydraulic filters are used extensively in the mining industry for various applications, including roof supports, tunnelling and drilling machines, shearers, materials handling equipment, locomotives, hydraulic power packs, winches and haulages. 

In the power generation industry, equipment failures can be disastrous and the highest standards of cleanliness are needed to protect system components and prevent malfunction of essential safety control systems. Hydraulic filters are also used extensively on off-shore rigs and in the production of industrial chemicals. 

In the oil industry, hydrostatic transmissions on cranes, winches, well servicing equipment and so on, are fitted with hydraulic filters to help eliminate contamination-related pump or motor failures, and to increase valve service fife. Hydraulic filters are used to protect rotating machinery in petrochemical plants, such as turbines, pumps and compressors. 

In a broad sense, hydraulic filters may be described as high pressure, medium pressure and low pressure filters. High pressure filters will operate in excess of 400 bar working pressure, with flows of 4501/min (although some operate to more than 1000 bar and for flows up to 10001/min). They can be manifold mounted and include both single and duplex housings. 

Medium pressure hydraulic filters are suitable for a variety of pressure and return line applications. Typically, they can operate up to 250 bar maximum working pressure, with flows up to 800 1/min. They are often used as an alternative to spin-on filters, which can sometimes be underspecified for tough cyclic operating conditions. 

Low pressure hydraulic filters are typically designed for operating pressures up to 28 bar, with flows up to 1200 1/min. Generally they have a wide application range, particularly for industrial and mobile applications, including high flow tank top and tank top return line filters. Many versions are of the spin-on type and can be provided as dual flow assembly off-line filtration. Core-less low pressure filler elements contain no metal and are designed to minimize waste disposal. 

The filter medium and element construction employed for specific hydraulic filters is chosen on the basis of filter performance required, acceptable pressure drop, mechanical strength, compatibility with the fluid being used, and other working... 

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