Mechanical seals according to standards

Acc. to API 610/ API 682(API = American Petroleum Institute)

API standards are referred to world-wide mainly in the area of refineries, oil&gas, petrochemical industries.API 610 and API 682 are relevant specifically for mechanical seals and pumps. API 610(10th edition) is still being used for the "API Plans" (refer below) as well as the API Code (ref. below)

API Code:

1st letter B = balancedU = unbalanced

2nd letter S = single-actingT = double-acting (tandem/ unpressurized)D = double-acting (pressurized with barrier pressure)

3rd letter type of coverP = plain, without throttle bushT = throttle bush with quench, leakage and / or drainage connectionA = additional/ auxiliary seal (has to be stated)

4th letter secondary seal materials5th letter face materialsExample for sealing and material code:BSTFO = balanced, single-acting mechanical seal with throttle bush, with dynamic and static secondary seals (O-rings) made of FKM and seal faces/ secondary seats made of tungsten carbide against silicon carbide

API 682 (3rd edition) is the up-to-date version (also coverd by ISO 21049).API 682 (3rd edition) specifies different Sealing Systems using as parameters: category, configuration (arrangement), seal type and API plan(s).

For Example: a Mechanical Seal designated as: C2 A1 A 3161 is a Mechanical Seal according to Category 2: Arrangement 1: Seal type A: 3161:

up to 41 bar; 400°Csingle seal/cartridgebalanced, inboard, pusher type sealAPI plan 31 and 61

For further details refer API 682 (3rd edition); further Information through www.api.org API plans for various circulation systemsThe most widely used API plans: API plan 01:Inherent product circulation from pump pressure connection to mechanical seal

API plan 11: Inherent product circulation from pressure connection via orifice to mechanical seal

API plan 32: Auxiliary flushing/ auxiliary injection with pure liquid to mechanical seal

API plan 52:pressureless, circulating quench - external vessel (thermosiphon and/or forced circulation); tandem mechanical seal

API plan 53: pressure superimposed, circulating quench - external vessel (thermosiphon and/ or forced circulation), back-to-back arrangement

API plan 62: external quench (steam, gas, water)

(For further, also more detailded information refer to chetra@chetra.de or www.api.org.)

Typ207A

single-acting preassembled cartridge mechanical

seal ready for operation balanced independent of direction of rotation multiple springs (protected) stationary design

Dimensions: 20-100 mm(also in inches)

pmax: 50 bar t: -20°C...+220°C

(acc. to secondary seal)

vmax: 35 m/s

Single seal for almost all applications in the area of refineries and petrochemical industry up to a max. of 220°C

Mechanical seal complete with throttle bush, circulation and quench connections

Universal high-quality material design with exchange components

Specifically suitable for standardization measures = shortening of repair time = increased availability factor of plant

Upgrade of MTBF/ MTBR value

Typ851T

double-acting preassembled cartridge mechanical

seal ready for operation balanced independent of direction of rotation multiple springs

Dimensions: 20-200 mm(also in inches)

pmax: 50 bar t: -120°C...+315°C

(acc. to secondary seal)

vmax: 25 m/s

Operation: API plan 52

Safety tandem mechanical seal, specifically suited for sealing of easy inflammable or spontaneously inflammable media, light hydrocarbons, LPG/ liquid gas, solvents and similar media in connection with flare; also for low temperature applications.

Special seal face geometry as well as use of excl. solid seal face/ stationary seats combine to form mechanical seal with lowest level of seal face distortion when exposed to compressive load and thermic pressure - leading to higher safety of operation and improved service life.

Mechanical seal complies with TA-Luft-requirements as well as with TÜV-LPG regulation TRB 1801.

As double-acting mechanical seal in back-to-back arrangement available: style 851BOperation: API plan 53 (higher barrier fluid pressure) with adequate auxiliary equipment (supervision of measured values recommended) specifically suited for:sealing of toxic and explosive media, e.g. aromatics like benzene, toluene, xylol and others.

Typ875

double-acting preassembled cartridge mechanical

seal ready for operation balanced independent of direction of rotation metal bellows

Dimensions: 30-150 mm(also in inches)

pmax: 28 bar t: -40°C...+400°C

vmax: 25 m/s

Operation: API plan 52

Guided and optimized circulation guiding for better cooling in the area of seal faces

The refinery seal for "hot" pumps, for sealing of hot-oils, for hot cracking products with catalyzer, in FCC plants and others (acc. to use of adequate auxiliary equipment)

API 682API 682 "Sealing systems for centrifugal pumps" refers to pumps used in refineries/ petrochemical industry (hydrocarbon-processing industries).

API 682 specifies cartridge (cartridge preassembled) mechanical seals, as well as dynamic test runs for all types of mechanical seals and arrangements with defined conditions.

API 682 requires continuous operation of at least 3 years, increased safety of operation and simplified maintenance. Arrangement and types of seals:Arrangement 1: single seal

Arrangement 2: double seal without pressurizationArrangement 3: double seal with pressurizationType A: O-ring seal/group springbackingType B: seal with metal bellows, with O-ring secondary sealsType C: seal with metal bellows, with graphite secondary sealsType SD: special sealing design

Dimensions from 30-120 mm (also in inches)

API 682 CHETRA mech. seal ApplicationA1 207A

pmax:t: vmax:

50 bar -40°C...+220°C 25 m/s

universal for applications non-hydrocarbons, volatile and non-volatile hydrocarbons, alkaline solutions, amines, acids, crude oil

B1 700Apmax:t: vmax:

25 bar-40°C...+260°C25 m/s

hydrocarbon condensatefuel oil (heavy)hydrocarbons (general)

C1 700SApmax:t: vmax:

25 bar-80°C...+400°C25 m/s

heavy gas oil; high temp. up to 350°Cheat transfer oils

A2 851T-Apmax:t: vmax:

50 bar -120°C...+260°C 25 m/s

easy and self-inflammable media,light hydrocarbons,LPG, solvents a.o. (in connection with flare)

A3 851B-Apmax:t: vmax:

50 bar -120°C...+260°C25 m/s

toxic, highly explosive media, e.g. aromatics like benzene, toluene, xylol

C2 875Apmax:t: vmax:

28 bar -40°C...+400°C 25 m/s

high temperature applications- hot-oils- hot cracking products with catalyzer (auxiliary equipment required, dep. on application)

SD 2 und 3 881D-Apmax:t: vmax:

50 bar -120°C...+280°C 35 m/s

specifically difficult environment, such as: solid material, frequent changing of operating conditions; mechanical seal with double pressure balance

Materials:Metal components 316SSSprings: Hastelloy C (ZM.Cabot)Secondary seals: fluorine elastomer/ graphite Seal face/ stat. seats: hard carbon, reaction bounded silicon carbideThrottle bush: carbonMetal bellows: Inconel 718 / Hastelloy C