1、1,API Piping Plans API 冲洗方案,November 2004,JC Tianjin Training Module 4.3,Seal Environment 密封环境,API Piping Plans API 冲洗方案,Integral (internal) recirculation from pump discharge to seal,Advantage- No external pipingLimitations- Changing flow raterequired dismantling of pump- For clean pumpages only,API
2、 Piping Plans API 冲洗方案,Points to Note for API Plan 02: - The injection tapping is used for venting prior to startup. - API plan 02 is often used together with plan 62, especially on high temperature bellows seals.,API Piping Plans API 冲洗方案,No flushing to the mechanical seal (dead-ended),Points to No
3、te for API Plan 11: - Use an orifice to restrict the flow rate if the discharge pressure is 3 bar higher than seal chamber pressure. - Use on clean and low abrasives duties,API Piping Plans API 冲洗方案,Seal Flushing By-Pass from Discharge 单密封通过出口进行冲洗,Recirculation from seal chamber through a flow contr
4、ol orifice and back to pump suction,Points to Note for API Plan 13: - Use an orifice to restrict the flow rate if the seal chamber pressure is 3 bar higher than suction pressure. - handle abrasives duty better than API plan 11 - higher seal chamber pressure to suppress vaporisation,API Piping Plans
5、API 冲洗方案,+,=,Points to Note for API Plan 14:- Flow back to suction side will evacuate vapours that may collect in seal chamber. - Recommended for light hydrocarbon service.,API Piping Plans API 冲洗方案,Recirculation from pump discharge through a flow control orifice and cooler to seal Open Loop Cooling
6、 Circuit,Cooling Water Outlet,Cooling Water Inlet,API Piping Plans API 冲洗方案,Recirculation from a pumping ring in the seal chamber through cooler and back to seal Closed Loop Cooling Circuit,Throat bushing,Suction,Discharge,18 - 24“,Vent at highest point of the piping,Cooling Water Outlet,Cooling Wat
7、er Inlet,mechanical seal with pumping ring,Heat exchanger,API Piping Plans API 冲洗方案,Points to note for API Plan 23:Thermosyphon design * heat exchanger 18 to 24“ above pump centre line.* Prevent overheating in standby and startup. Install close fitting neck bushing at the bottom of seal chamber to i
8、solate the heat from the impeller end. Used on high temperature applications to minimise heat load on the cooler by cooling only small amount of liquid that is recirculated. For high temperature boiler feed pump applications Other applications * high temperature liquid close to bubble point.,API Pip
9、ing Plans API 冲洗方案,Recirculation from pump discharge through a cyclone separator delivering clean fluid to the seal and fluid with solids back to pump suction line,API Piping Plans API 冲洗方案,Points to Note for API Plan 32:- Chose a proper source of seal flush to eliminate the potential for vaporisati
10、on of the injected fluid and to avoid contamination of the fluid being pumped with the injected flush. - Install a labyrinth bushing at the bottom of the stuffing box to control the flushing and pressure if necessary.,API Piping Plans API 冲洗方案,Single Seal Flushing from External Source 单密封通过外部来源进行冲洗,
11、Throat Bushing,Recirculation from pump discharge through a cyclone separator delivering clean fluid through a cooler and then to seal and fluid with solids back to pump suction line,Cooling Water Outlet,Cooling Water Inlet,API Piping Plans API 冲洗方案,Needle valve,External reservoir providing a dead-en
12、ded blanket of fluid to the quench connection of the gland.,Points to Note for API Plan 51: - Dead ended blanket on atmospheric side of seal to prevent freezing of moisture. Seal face will not stick together when the pump started.Typical application : Pump operating below 0 C - API 610 8th Edition h
13、as eliminated this piping plan.,API Piping Plans API 冲洗方案,Piping Systems,API Piping Plans API 冲洗方案,A fluid used as a lubricant or buffer between dual mechanical seals. The buffer fluid is always at a pressure lower than the pump process pressure being sealed.,A fluid which is introduced between dual
14、 mechanical seals to completely isolate the pump process liquid from the environment.Pressure of the barrier fluid is always higher than the pump process pressure being sealed.,The purpose of fluid circulation is to remove heat from mechanical seal,API Piping Plans API 冲洗方案,On applications below amb
15、ient temperature, circulation of barrier fluid may not be desirable.The atmosphere will heat the reservoir and consequently add heat to the seal area.,Fluid circulation by temperature difference between the seal and reservoir. Higher temperature liquid at seal has lower density rises to the reservoi
16、r. Lower temperature liquid at reservoir has higher density falls to the seal to provide cooling.,External Force Circulation,Thermosyphon,Pumping Ring,Dead Ended,API Piping Plans API 冲洗方案,Points to Note for API Plan 52:Typically used with an Arrangement 2 unpressurised dual seal. During normal opera
17、tion, circulation is maintained by an internal pumping ring. The reservoir is usually continuously vented to a vapour recovery system and is maintained at a pressure less than the pressure in the seal chamber.,Pressure Gauge,Level Gauge,Fill valve,Orifice,Drain,Level Switch (H),Level Switch (L),Pres
18、sure Switch,(Normally Open),Vent valve,External reservoir providing buffer fluid for the outer seal of an unpressurised dual seal arrangement.,API Piping Plans API 冲洗方案,Pressure Gauge,Level Gauge,Level Switch (L),Vent Valve (Normally Close),Orifice,Pressure Switch,External Pressure Source,One-way Bl
19、ock Valve (Normally Open),Points to Note for API Plan 53:Typically used with an Arrangement 3 pressurised dual seal. During normal operation, circulation is maintained by an internal pumping ring.The reservoir pressure is greater than the process pressure being sealed.,External reservoir providing p
20、ressurised barrier fluid for the outer seal of an pressurised dual seal arrangement.,Drain,API Piping Plans API 冲洗方案,Points to Note for API Plan 54:Typically used with an Arrangement 3 pressurised dual seal. During normal operation, circulation is maintained by an external pump or pressure system.Th
21、e circulating barrier fluid pressure is greater than the process pressure being sealed.,External barrier fluid system providing pressurised barrier fluid for the outer seal of an pressurised dual seal arrangement,API Piping Plans API 冲洗方案,Safe to use, handle, store Stable liquid at ambient temperatu
22、res Not a VOC, VHAP or other regulated compound Non flammable Non foaming when pressurised Clean and good lubricity Compatible with process fluid Compatible with seal materials Good heat transfer properties Good flow qualities at very low temperatures Low solubility of gas Local availability Low cos
23、t,VOC : Volatile Organic Compound VHAP : Volatile Hazardous Air Polutants,Selection of Buffer / Barrier Fluid,API Piping Plans API 冲洗方案,Tapped connections for the purchasers use,Point to Note for API Plan 61:Typically this plan is used when the purchaser is to provide fluid (such as steam, gas, or w
24、ater ) to an auxiliary sealing device.,API Piping Plans API 冲洗方案,Points to Note for API Plan 62:The quench may be required to prevent solids from accumulating on the atmospheric side of the seal. Typically used with a close-clearance throttle bushing.,API Piping Plans API 冲洗方案,Single Seal Quench fro
25、m External Source 单密封通过外部急冷,API 682 2nd Edition API 682 第二版 New Piping Plans 新的冲洗方案,Plan 14 (Plan 11+13) Plan 53s - Arrangement 3, Contacting Wet (CW) Seals 53a traditional configuration 53b bladder accumulator 53c piston pot/ accumulator Containment Seal Plan 72 Arrangement 2 w/ Containment Seal (C
26、S) Plan 75 Arrangement 2 w/ Containment Seal (CS) Plan 76 Arrangement 2 w/ Containment Seal (CS) Gas Barrier Seals Plan 74 Arrangement 3, Non-Contacting (NC) Seals,Plan 53a (A.4.12),Arrangement 3, Contacting Wet (CW) Seals Dual Pressurised (Double) Seals Utilises direct nitrogen blanket for pressure
27、 due to nitrogen entrainment in the barrier liquid API 682 limits the maximum nitrogen pressure to 10 barg, JC recommendation is maximum nitrogen pressure 21 barg, as long as the barrier fluid temperature is less than 120C,API 682 2nd Edition API 682 第二版 New Piping Plans 新的冲洗方案,Plan 53b (A.4.12),Arr
28、angement 3, Contacting Wet (CW) Seals Dual Pressurised (Double) Seals Utilizes bladder accumulator for pressure Bladder eliminates nitrogen contact with barrier liquid Allows for higher pressure applications,Configuration Includes: Accumulator Pressure Indicator Pressure Switch Heat Exchanger,API 68
29、2 2nd Edition API 682 第二版 New Piping Plans 新的冲洗方案,Plan 53c (A.4.12),Arrangement 3, Contacting Wet (CW) Seals Dual Pressurised (Double) Seals Utilizes piston pot for pressure,API 682 2nd Edition API 682 第二版 New Piping Plans 新的冲洗方案,Plan 53c (A.4.12),Allows for higher pressure applications Configuratio
30、n includes: Piston pot Pressure indicator Pressure switch Heat exchanger Level switch,Piston pot eliminates nitrogen contact with barrier liquid Piston provides constant pressure ratio to seals (1.1:1),Spring,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Barrier Fluid Temperature (7.3.4.1.1
31、) 隔离流体温度,Liquid barrier systems shall be designed such that that maximum temperature differential between the barrier fluid inlet and outlet immediately adjacent to the seal chamber is:8 degree C for glycol /water or diesel barrier fluids; and 16 degree C for mineral oil barrier fluid,Plan 11 with P
32、lan 53,Arrangement 3 may use Plan 11 & 53 Improved heat transfer Reverse pressure capability “Back to Back ” seals uses Plan 53,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 72 (A.4.16),Arrangement 2, w/ Containment Seal (CS) Dual Un-Pressurised (Tandem) Seals Dry-running secondary con
33、tainment seal Low pressure nitrogen sweep (purge) Sweeps primary leakage to collection system Dilutes primary leakage to lower emission levels Used in conjunction with Plan 75 or 76,CSV: containment seal vent CSD: containment seal Drain GBI: gas buffer inlet FIL: coalescing filter,API 682 2nd Editio
34、n API 682 第二版New Piping Plans 新的冲洗方案,Plan 74 (A.4.17),Arrangement 3, Non-contacting Seals (NC) Dual Pressurised (Double) Gas Barrier Seals Nitrogen gas barrier 1.75 - 2 bar (25-30 psi) above seal chamber pressure Zero emissions Essentially a T2800 panel,GBI: gas buffer inletGBO: gas buffer outlet (N
35、C) (used only to depressurize),API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 75 (A.4.18),Arrangement 2, w/ Containment Seal (CS) Dual Un-Pressurised (Tandem) Seals Dry-running secondary Condensate collection reservoir (8.6.5.2) Used when primary seal leakage may condense ( does not com
36、pletely vaporize) May be used in conjunction with Plan 72,API 682 2nd Edition API 682 第二版New Piping Plans 新的冲洗方案,Plan 76 (A.4.19),Arrangement 2, w/ Containment Seal (CS) Dual Un-Pressurised Seals (Dry-running secondary) Primary leakage routed to flare or vent Used when primary seal leakage will not condense (completely vaporizes) Essentially a 48SC or 28LD panel leakage detection May be used in conjunction with Plan 72,API 682 2nd Edition API 682 第二版 New Piping Plans 新的冲洗方案,
