1、1,API Piping Plans API 沖洗方案,November 2004,JC Tianjin Training Module 4.3,Seal Environment密封環(huán)境,API Piping Plans API 沖洗方案,Integral (internal) recirculation from pump discharge to seal,Advantage - No external piping Limitations - Changing flow rate required dismantling of pump - For clean pumpages only

2、,API Piping Plans API 沖洗方案,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 沖洗方案,No flushing to the mechanical seal (dead-ended),Points t

3、o Note 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 沖洗方案,Seal Flushing By-Pass from Discharge 單密封通過出口進(jìn)行沖洗,Recirculation from seal chamber through a flow c

4、ontrol 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 Pl

5、ans API 沖洗方案,+,=,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 沖洗方案,Recirculation from pump discharge through a flow control orifice and cooler to seal Open Loop Co

6、oling Circuit,Cooling Water Outlet,Cooling Water Inlet,API Piping Plans API 沖洗方案,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

7、 Water Inlet,mechanical seal with pumping ring,Heat exchanger,API Piping Plans API 沖洗方案,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

8、 to isolate 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.,AP

9、I Piping Plans API 沖洗方案,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 沖洗方案,Points to Note for API Plan 32: - Chose a proper source of seal flush to eliminate the potential for vapo

10、risation 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 沖洗方案,Single Seal Flushing from External Source 單密封通過外部來

11、源進(jìn)行沖洗,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 沖洗方案,Needle valve,External reservoir providing a d

12、ead-ended 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 Ed

13、ition has eliminated this piping plan.,API Piping Plans API 沖洗方案,Piping Systems,API Piping Plans API 沖洗方案,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 betwe

14、en dual 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 circulationis to remove heat from mechanical seal,API Piping Plans API 沖洗方案,On applications be

15、low ambient 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

16、reservoir. 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 沖洗方案,Points to Note for API Plan 52: Typically used with an Arrangement 2 unpressurised dual seal. During nor

17、mal operation, 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

18、 (L),Pressure Switch,(Normally Open),Vent valve,External reservoir providing buffer fluid for the outer seal of an unpressurised dual seal arrangement.,API Piping Plans API 沖洗方案,Pressure Gauge,Level Gauge,Level Switch (L),Vent Valve(Normally Close),Orifice,Pressure Switch,External Pressure Source,On

19、e-way Block 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 pr

20、oviding pressurised barrier fluid for the outer seal of an pressurised dual seal arrangement.,Drain,API Piping Plans API 沖洗方案,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

21、 system. The 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 沖洗方案,Safe to use, handle, store Stable liquid at ambien

22、t temperatures 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 availabil

23、ity Low cost,VOC : Volatile Organic Compound VHAP : Volatile Hazardous Air Polutants,Selection of Buffer / Barrier Fluid,API Piping Plans API 沖洗方案,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 stea

24、m, gas, or water ) to an auxiliary sealing device.,API Piping Plans API 沖洗方案,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 沖洗方案,Single Se

25、al Quench from External Source 單密封通過外部急冷,API 682 2nd Edition API 682 第二版New Piping Plans 新的沖洗方案,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/ Contain

26、ment Seal (CS) 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

27、for pressure 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 新的沖洗方案,Plan 53b

28、(A.4.12),Arrangement 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 Exch

29、anger,API 682 2nd Edition API 682 第二版New Piping Plans 新的沖洗方案,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 新的沖洗方案,Plan 53c (A.4.12),Allows for higher pressure applications C

30、onfiguration 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 新的沖洗方案,Barrier Fluid Temperature

31、 (7.3.4.1.1)隔離流體溫度,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,Pla

32、n 11 with Plan 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 新的沖洗方案,Plan 72 (A.4.16),Arrangement 2, w/ Containment Seal (CS) Dual Un-Pressurised (Tandem) Seals Dry-running secondary containment 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 filte