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36 Cards in this Set
- Front
- Back
- 3rd side (hint)
Seals |
Devices that prevent the passage of fluids along the rotating shaft. |
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Main Purpose of Mechanical Seals |
To reduce the leakage of fluids to parts per million rather than drops per minute. |
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Packing |
The sealing surrounds the shaft and closes down the clearances around it so that very little product can escape from the space between the packing and the shaft. |
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Primary Sealing Element |
The primary ring is the rotating face of the mechanical seal that is fixed to the shaft but held closely against the casing by means of a spring and hydraulic pressure. |
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Mating Ring |
Stationary face that is mounted in the gland which is mounted on the pump casting. |
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Secondary Seal Element O-Ring |
Used to prevent leakage along the shaft through the inner surface of the primary ring and the mating ring. |
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Load Element Coil Spring |
Used to provide mechanical tension for the sealing between the two sealing faces. |
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Hardware Elements |
Collar, sleeve, and gland plate are the additional hardware elements of a Mechanical seal. Used to support the coil spring. |
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Pusher Type Seal |
Move axially along the rotating shaft to maintain the contact between the two seal faces. They are designed to compensate for the wearing out of the seal faces or misalignment of seal faces with respect to the pump shaft. |
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Non-Pusher Type Seal |
Pushes the rotating faces towards the stationary face by the combined force of bellows and liquid pressure. |
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Cartridge Seal |
A complete seal assembly that can be installed in the field with minor disassembly to the pump. Can be any type of mechanical seal arrangement |
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Dry Gas Seal |
Non-contacting, dry-running mechanical seal that consists of a rotating seal face and a stationary seal face Nitrogen or Gas supplied to the seal prior to starting the equipment. |
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Signal Seal |
Used on products where a small leakage to the atmosphere is acceptable. |
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Double Seal Duel or Tandem Seal |
Used where the leakage of a product to the atmosphere cannot be tolerated, or where fluid pressure is dirty or unstable, or there is a danger of negative pressure being created. back-to-back or face-to-face seals |
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Seal Flush System |
Used to cool and lubricate the seal faces by introducing a small amount of fluid into the seal chamber close to the seal faces. |
discharge side of process |
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Quench |
Neutral fluid, such as steam or water, which is introduced on the atmosphere side if the seal to reduce the formation of a solid that may interfere with the seal movement. |
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Quench Types |
Steam on Hydrocarbon Water on Caustic |
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Seal Cooler |
Heat exchanger that is used for cooling the flush |
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Cooling Water Supply and Return Lines |
Connected to the seal cooler for supplying cooling water to the flush. |
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Seal Reservoir (seal pot) |
Store the fluid that is passed through the seal faces A non-pressurized system uses buffer fluid |
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Instruments |
Used to indicate or alarm the operators when the process variables exceed the set limits. Pressure gauges Pressure Switches Level Switches Flow Meters |
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Single Mechanical Seals |
Has the lowest leakage ratio if seals |
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Coil Spring |
The component that is required to apply the mechanical tension to the primary and mating rings |
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Tandem (double or duel) |
Two identical seals that are arranged one behind the other |
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Quench |
Components of a seal support system used on the atmosphere side if the seal to reduce the formation of solids that may interfere with the seal movement. (Coke and Crystalzation) |
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Plugging of orifice |
Seal Problem- Differential temperature across the orifice |
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Throttled isolation valve or restriction in the quench line |
Lack of quench flow (steam or water) |
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Cavitation |
The formation and subsequent imploding of gas pockets in a pump, causing damage to the internal parts of the pump. Low Net Positive Suction Head aka Lack of Suction |
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Gas Pockets |
Lack of lubrication to the seals, which cause the seals to overheat. Leads to seal failure. |
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Flashing |
Heat builds up in the sealing faces due to friction, the process fluid on the sealing faces begins to vaporize or flash Leaves Coke Banging of the seal faces |
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Improper Flushing |
Pump is running without proper flushing at the seal faces, ot causes excessive heat. Common Factors Plugged seal flush orifice Plugged flush line Flush not being cool enough |
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Improper Venting/ De-gassing |
Gas pockets move into the seal cavity, becomes difficult for the seal flush to force the gas pockets out of the seal cavity and lubricate the seal faces. |
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Plugging or Fouling in Seal Cooler |
Leads up to heating of the seal cavity |
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Poor or Bad Steam Quench |
Formation of coke or solids between the dealing faces may open or damage the seal |
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Poor or Bad Water Quench |
Formation of crystals on the atmosphere side of the seal faces Stops the seal faces from moving forward. |
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Improper Shaft Alignment |
Vibration of the pump, causes shorten of the seal life. |
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