Mechanical Seal Selector
Five questions about your duty, and you get a starting specification: elastomer, face pair and arrangement. It uses the same order of reasoning we use on site, so you can sanity check what you have been quoted.
What is the pump handling?
The fluid decides the elastomer before anything else does.
Mechanical seal selection questions
How do I choose the right mechanical seal for my pump?
Work through the fluid, the maximum temperature, the seal chamber pressure, whether solids or dry running are present, and what happens when the pump stops. Those five answers decide the elastomer, the face pair and whether you need a single or a double seal. This selector applies that same order and gives you a starting specification in under a minute.
Which elastomer should I use in my mechanical seal?
Nitrile for oils and water to about 100C, EPDM for hot water, steam and caustics but never with mineral oil, FKM for oils, fuels and many chemicals to about 200C, and FFKM where the chemistry is mixed or the temperature is above 200C. The elastomer is the most common cause of a chemically driven seal failure.
Which seal face materials are best?
Carbon against silicon carbide is the general purpose choice on clean fluids. Silicon carbide against silicon carbide handles abrasives and aggressive chemistry but will not tolerate dry running. Tungsten carbide is used where pressure and shock loading are high.
When do I need a double mechanical seal?
When the fluid is toxic, flammable, crystallising or must not reach atmosphere, when there are heavy solids, or when the pump stopping stops the plant. A double seal needs a barrier or buffer system, so it should not be fitted where a correctly specified single seal would last.
Is this selector a substitute for a proper specification?
No. It gives you a sound starting point based on the five factors that decide most seal specifications. Send us the pump make and model, shaft diameter, fluid concentration and any standard you must meet and we will confirm or correct it, including telling you when a cheaper option is the right one.