Mechanical seal
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This document discusses mechanical seals and tandem seals used in equipment. It describes the components of mechanical seals including rotary elements like carbon rings and stationary elements like tungsten carbide rings. It discusses types of mechanical seals such as single seals, double bellow seals, and unbalanced seals. It explains that hydraulic balance percentage below 65% can cause leaks. The document also covers barrier fluids used with tandem seals, circulating barrier fluids and quench fluids to control heat and removal, and suitable barrier fluids for different temperature ranges.
Mechanical seal
- 1. 1 Equipment GLAND THROAT BUSH FOLLOWER PACKING LANTERN RING SLEEEVE PACKING WITH SLEEVE PACKING WITH SLEEVE * Wear is on the sleeve
- 2. 2 Horizontal Surface wear Shaft wear Equipment Now it essential to find a solution to avoid shaft wear, Such as finding another surface of another parts to be worn but easy and cheap to be replaced, It is the MECHANICAL SEAL
- 3. 3 Equipment Vertical surface wear Scarifying elements
- 4. 4 Rotary Elements 1 - Carbon ring 2 - Snap Ring 3 - O Rings 4 - Springs 5 - Sleeve Stationary Element Tungsten Carbide ring Or Silicon Carbide ring Equipment Single mechanical seal Single mechanical seal
- 5. 5 Double Mechanical seal Bellow type Double Mechanical seal Bellow type BELLOW BELLOW
- 6. 6 Unbalanced mechanical seal Stationary Carbon ring Product + Springs Product + Springs Contact face pressure Contact face pressure > PRESSURE P STRESS S
- 7. 7 FACE AND SEAT AREA EQUAL 100% BALANCE FACE AND SEAT AREA EQUAL 100% BALANCE F = P * A F = S * A P * A = S * A P = S A = Contacted Surface area S = Contacted Surface stress P = Product + Spring pressure F = Acting force S P = 100 % A P Carbon ring A S Stationary ring
- 8. 8 P S A1 ( projected area of P ( ) product + spring pressure ( ) contacted surface stress ( = A ( contacted surface area ( 120 cm2 230 cm2 = Mechanical seal has the following data : A = contacted surface area = 230 cm2 A1 = ( projected area of P) = 120 cm2 Calculate the hydraulic balance Percentage SOLUTION = . 0 52 * 100 = 52 % Hydraulic balance % is less than 65 % This Mechanical is prone to leak Hydraulic balance % is less than 65 % This Mechanical is prone to leak
- 11. 11 Heat control / removal API Plan 21 API Plan 21
- 14. 14 Tandem Seal Tandem Seal Barrier fluid Circulation Product Circulation Equipment Pp Barrier fluid Circulation Barrier fluid Circulation PBF = 1 bar max
- 15. 15 Barrier fluid Type Barrier fluid Type Temperature Range Temperature Range Barrier fluid Barrier fluid - 120 to - 90 Propanol - 120 to - 90 Propanol 0 C - 90 to - 30 Methanol - 90 to - 30 Methanol 0 C - 30 to + 20 Kerosene or Hydraulic oil - 30 to + 20 Kerosene or Hydraulic oil 0 C + 20 to + 200 L.G.O. or H.G.O . + 20 to + 200 L.G.O. or H.G.O . 0 C