Seeking help: The impact of the viscosity of the conveyed medium on the lifespan of gear pumps
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I have information on American Tuthill gear pumps, which states that with pure water as the fluid at a dynamic viscosity of 1.0 CPS at 20 degrees Celsius, the pump’s lifespan is 20,000 hours. What is the lifespan if a fluid with a viscosity of 0.5 CPS is used? Are there any empirical data on the lifespan of gear pumps in relation to viscosity? Thank you all.
The viscosity level has an impact on the lubrication of the pump; however, no information regarding the relationship between viscosity and lifespan has been found in the available documents. However, materials with high viscosity provide better lubrication for the pump compared to those with low viscosity; consequently, the pump’s lifespan is longer when transporting materials with high viscosity.
I am now using a gear pump to transport a fluid with a viscosity of 0.3 CPS, and I’m not sure about the pump’s lifespan. When I asked the supplier, their reply was just three words: “No problem.” I’ve looked up a lot of information, but I really can’t find any descriptions regarding the impact of the fluid’s viscosity on the lifespan of the pump’s gears. Life testing is carried out through actual operation, which is a rather unfortunate situation.
Reply to 3# NingZY: When considering the viscosity of a medium, it is more accurate to say that we are actually taking into account the lubricity of the material； The materials we come into contact with in daily life generally have poor lubricity when their viscosity is 1 or less, and they are also usually highly volatile; thus, a gas-liquid mixture is formed during transportation. For example, water, ethanol, methanol, benzene, gasoline, diesel ； While kerosene, vegetable oil, lubricating oil, fuel oil, hydraulic oil, etc., have better lubricating properties ； Pumps have a longer service life when used for pumping (good lubrication results in less wear between the gears) ； When the viscosity of the material reaches levels similar to those of toothpaste and sealants, its lubricity becomes poor as well; in such cases, extending its service life is possible only by selecting appropriate materials and reducing the rotation speed as well as the pressure difference. According to your description, if the viscosity of the material is 0.3CP ； If external gear gears are used and the gear material is metal, it is necessary to determine the appropriate pressure and speed in order to ensure a long service life. A lower speed helps to reduce wear, but if the speed is too low, no pressure can be generated at all ； To generate pressure, it is necessary to increase the rotational speed, which leads to increased wear and a shortened lifespan of the gears! Therefore, if the material and hardness of the gear are not special types, under your current operating conditions, a regular gear pump that can last more than half a year already constitutes a pump of good quality!
Reply to 2# lxn_663: Thank you to the moderator for your support and encouragement!