API_Piping_Plans_join_crane_约翰克兰机械密封冲洗方案

7/31/2019 API_Piping_Plans_join_crane_

1/34

2001 John Crane EAA 1

API Piping PlansAPI

November 2004

JC Tianjin Training

Module 4.3

Seal Environment


2/34

API Piping Plans API


3/34

Integral (internal) recirculation

from pump discharge to seal

Advantage- No external piping

Limitations- Changing flow rate

required dismantling of pump- For clean pumpages only



4/34

Points to Note for API Plan 02:

- The injection tapping is usedfor venting prior to startup.

-API plan 02 is often usedtogether with plan 62,

especially on high temperaturebellows seals.


No flushing to the mechanical seal (dead-ended)


5/34

Points to Note for API Plan

11:

- Use an orifice to restrict theflow rate if the dischargepressure is 3 bar higher thanseal chamber pressure.

- Use on clean and lowabrasives duties


Seal Flushing By-Pass from Discharge


6/34

Recirculation from seal chamber through a flow

control orifice and back to pump suction


- Use an orifice to restrict the flow rate ifthe seal chamber pressure is 3 bar higherthan suction pressure.

- handle abrasives duty better than APIplan 11

-higher seal chamber pressure tosuppress vaporisation



7/34

+ =Points to Note for APIPlan 14:

- Flow back to suctionside will evacuate

vapours that maycollect in seal chamber.

- Recommended forlight hydrocarbonservice.



8/34

Recirculation from pump dischargethrough a flow control orifice and cooler to seal

Open Loop Cooling Circuit

CoolingWaterOutlet

CoolingWaterInlet



9/34

Recirculation from a pumping ring in the sealchamber through cooler and back to seal

Closed Loop Cooling Circuit

Throat bushing

Suction

Discharge

18 - 24"

Vent at

highestpoint ofthe piping

CoolingWaterOutlet

CoolingWaterInlet

mechanical sealwith pumping ring

Heat exchanger



10/34

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 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 liquidthat is recirculated.

For high temperature boiler feed pump applications

Other applications* high temperature liquid close to bubble point.



11/34

Recirculation from pump discharge through a cycloneseparator delivering clean fluid to the seal

and fluid with solids back to pump suction line

Clean overflow

Underflow

Inlet



12/34

Points to Note for API

Plan 32:

- Chose a proper source of sealflush to eliminate the potentialfor vaporisation of theinjected fluid and to avoidcontamination of the fluidbeing pumped with the

injected flush.- Install a labyrinth bushing atthe bottom of the stuffing boxto control the flushing andpressure if necessary.


Single Seal Flushing from External Source

ThroatBushing


13/34

Recirculation from pump discharge through a cycloneseparator delivering clean fluid through a cooler and then to

seal and fluid with solids back to pump suction line

CoolingWaterOutlet

CoolingWaterInlet



14/34

Needlevalve

External reservoir providing adead-ended blanket of fluid to thequench connection of the gland.


-- Dead ended blanket on atmosphericside of seal to prevent freezing ofmoisture. Seal face will not sticktogether when the pump started.

Typical application :Pump operating below 0 C

-- API 610 8th Edition has eliminatedthis piping plan.



15/34



16/34

A fluid used as a lubricant or buffer betweendual mechanical seals.

The buffer fluid is always at a pressure lowerthanthe pump process pressure being sealed.

A fluid which is introduced between dual

mechanical seals to completely isolate the pumpprocess liquid from the environment.

Pressure of the barrier fluid is always higherthanthe pump process pressure being sealed.

The purpose of fluid circulationis to remove heat from mechanical seal



17/34

Pumping ring

Pump

On applications belowambient temperature,circulation of barrier fluid maynot be desirable.

The atmosphere will heatthe reservoir andconsequently add heat to the

seal area.

T2

T1

Fluid circulation bytemperature differencebetween the seal andreservoir.

Higher temperatureliquid at seal has lowerdensity rises to the

reservoir. Lower temperature liquidat reservoir has higherdensity falls to the seal toprovide cooling.



18/34


Typically used with an Arrangement 2unpressurised dual seal.

During normal operation, circulation ismaintained by an internal pumping ring.

The reservoir is usually continuouslyvented to a vapour recovery system and

is maintained at a pressure less than thepressure in the seal chamber.

Pressure Gauge

Level GaugeFill valve

Orifice

Drain

Level Switch (H)

Level Switch (L)

Pressure Switch

(Normally Open)Vent valve

External reservoir providing buffer fluidfor the outer seal of an unpressurised

dual seal arrangement.



19/34

Pressure Gauge

Level GaugeLevel Switch (L)

Vent Valve(Normally Close)

Orifice

Pressure SwitchExternal PressureSource

One-way Block Valve(Normally Open)


Typically used with an Arrangement 3pressurised dual seal.

During normal operation, circulation ismaintained by an internal pumping ring.

The reservoir pressure is greater thanthe process pressure being sealed.

External reservoir providing pressurisedbarrier fluid for the outer seal of anpressurised dual seal arrangement.

Drain



20/34


Typically used with anArrangement 3 pressuriseddual seal.

During normal operation,circulation is maintained byan external pump orpressure system.

The circulating barrier fluidpressure is greater than theprocess pressure beingsealed.

External barrier fluid system providing pressurised barrier fluid

for the outer seal of an pressurised dual seal arrangement



21/34

Safe to use, handle, store

Stable liquid at ambient 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 availability

Low cost VOC : Volatile Organic CompoundVHAP : Volatile Hazardous Air Polutants



22/34

Tapped connections for the purchasers use

Point to Note for API Plan 61:

Typically this plan is usedwhen the purchaser is toprovide fluid (such as steam,gas, or water ) to an auxiliarysealing device.



23/34


The quench may be requiredto prevent solids fromaccumulating on theatmospheric side of the seal.

Typically used with a close-clearance throttle bushing.


Single Seal Quench from External Source

API 682 2 d Edi i


24/34

API 682 2nd Edition API 682 New Piping Plans

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 (CS)



Gas Barrier Seals

Plan 74 Arrangement 3, Non-Contacting (NC) Seals

API 682 2 d Edi i


25/34

Plan 53a(A.4.12) Arrangement 3, Contacting Wet (CW) Seals

Dual Pressurised (Double) Seals

Utilises direct nitrogen blanket for pressure

due to nitrogen entrainment in the barrier liquid

API 682 limits the maximum nitrogen pressure to 10 barg, JCrecommendation is maximum nitrogen pressure 21 barg, as long as

the barrier fluid temperature is less than 120 C


API 682 2nd Editi


26/34

Plan 53b(A.4.12) Arrangement 3, Contacting Wet (CW) Seals


Utilizes bladder accumulator for pressure

Bladder eliminates nitrogen contact with barrier

liquid Allows for higher pressure applications

ConfigurationIncludes:

Accumulator

PressureIndicator

Pressure Switch

Heat ExchangerBI

BO

TI BIBO

FWhen

Specified


API 682 2nd Editi API 682


27/34

Plan 53c(A.4.12) Arrangement 3, Contacting Wet (CW) Seals


Utilizes piston pot for pressure

BI

BO

BIBOF

WhenSpecified




28/34

Plan 53c(A.4.12)

Allows for higher pressureapplications

Configuration 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 682New Piping Plans


29/34

Barrier Fluid Temperature (7.3.4.1.1)

Liquid barrier systems shall be designed such thatthat maximum temperature differential between thebarrier fluid inlet and outlet immediately adjacentto the seal chamber is:

8 degree C for glycol /water or diesel barrierfluids; and

16 degree C for mineral oil barrier fluid



30/34

Plan 11 with Plan 53

Arrangement 3 may use Plan 11 & 53

Improved heat transfer

Reverse pressure capability

Back to Back seals uses Plan 53




31/34

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 ventCSD: containment seal DrainGBI: gas buffer inletFIL: coalescing filter


API 682 2nd Edition API 682


32/34

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 inlet GBO: gas buffer outlet (NC)(used only to depressurize)




33/34

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

completely vaporize) May be used in conjunction with Plan 72




34/34

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


Documents

API_Piping_Plans_join_crane_约翰克兰机械密封冲洗方案