Fluid
Proposal for the selection of hydraulic clindern
The proposal for the selection of equipment features depend on a number of operating conditions.
The correct equipment is crucial for the hydraulic cylinder's quality and reliability, its friction force and its wear behaviour.
Beside the operating temperatures and the travelling distances and speeds determined in the hydraulic design, especially the fluid should be considered:
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Hydraulic oil HLP or HLPD according to DIN 51502 and DIN 51524. HLP is a mineral oil with anti-ageing, anti-corrosion and anti-wear additives. These are the most commonly used for hydraulic applications today. HLPD has these as well, and also detergents and dispersants. Due to the demulsifiers they contain, HLPD oils are better for corrosion protection than HLP oils. They are used in humid environments or for interval operation. |
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Flame-resistant hydraulic fluid HFA HFA fluids are oil-in-water-emulsions with a water content of more than 80%. |
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Flame-resistant hydraulic fluid HFC HFC fluids are aqueous polymer solutions with a water content of more than 35%, usually water-glykol mixtures. Their viscosity is similar to that of mineral oil. |
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Flame-resistant hydraulic fluid HFD HFD fluids are water-free synthetic ester fluids. There are HFDR, phosphoric esters and HFDU, which includes all other synthetic fluids such as polyester or diester. |
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Brake fluid DOT 4 Brake fluids are poly-glycol-based hydraulic fluids. According to standard no. 116 of the DOT, United States Department of Transportation, there are three classes - DOT 3, DOT 4, DOT 5. Class DOT 5 is further divided into silicone-based DOT 5 and glycol-based DOT 5.1. |
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Hydraulic fluid for PU/ NBR-based seals If the fluid used is definitely compatible with PU, NBR und PTFE, the sealing materials commonly used in hydraulic systems. This applies for example to most HLP and HLPD hydraulic oils. |
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NBR-based hydraulic fluid for seals If the fluid used is definitely compatible with the sealing materials NBR und PTFE. These are for example hydrous media. |
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FKM-based hydraulic fluid for seals If the fluid used is definitely compatible with the sealing materials FKM and PTFE. These are for example some HFD fluids. |
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EPDM-based hydraulic fluid for seals If the fluid used is definitely compatible with the sealing materials EPDM and PTFE. These are for example brake fluids and some HFD fluids. |
The proposal issues are based on nothing but the operating conditions requested here. Due to potential factors unknown to us, we cannot take any responsibility for the correctness of these recommendations.
In case of other influencing factors, please contact our application support.
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