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Mechanical seals according to application (pumps)
    
    
  The main focus of our program are mechanical seals for difficult requirements of sealing technique, partly in special designs.

These types of CHETRA® mechanical seals are adapted to the operating conditions as well as to the aggregate to be sealed.

The following listed cases of application are examples, representing a large number of applications of CHETRA® mechanical seals.
      
      
     
  Heat transfer oils  
  Our concept for the sealing of heat transfer oils is to work without auxiliary cooling (up to a max. of 400C) by means of special double-acting tandem mechanical seals and use of quench vessels (thermosyhon).
     
770
  • double-acting / tandem
  • preassembled cartridge mechanical seal ready for installation
  • balanced
  • independent of direction of rotation
  • metal bellows
 
 
Dimensions: 30-115 mm
pmax: 16 bar (25 bar)
t:  400C
vmax: 25 m/s
  Operation: Quench pressurization / thermosyhon quench

The specific design and the materials used combine to make operation of this mechanical seal possible without expensive and often susceptible auxiliary cooling:
- cooling fin housing, guided and optimized "cold" quench runback a.o. measures dissipate heat and avoid cracking and the formation of oil carbon
- preferred materials: A Q2 G E4 G + A Q2 T

Other CHETRA® mechanical seals for the sealing of heat transfer oils and other "hot products" are: 700S, 711, 775, 875T
     

   
  LATEX/SB Latex/A-Latex a.o.
  The medium Latex demands more from a mechanical seal because of the inherent characteristic features of the medium as well as its tendency to clot.
     
861
862
  • double-acting
  • preassembled cartridge mechanical seal ready for installation
  • balanced
  • independent of direction of rotation
  • multiple springs (protected on the product side)
 
Dimensions: 50-200 mm
pmax: 50 bar
t: -120C...+315C
(acc. to secondary seal)
vmax: 35 m/s
 
   
  Guided circulation flow, protection of sealing elements essential for function a.o. special design features of the mechanical seal ensure reliable operation and high service life.

Application of solid hard alloy seal faces/ secondary seats with special seal face geometry and finish.
     

   
  Pipeline pumps
  Pipeline pumps deliver crude oil products as well as finished products. Because of pressure ratio as well as in connection with dimensions and number of revolutions (p.v factor) the mechanical seal must have robust design and material and be indifferent to solid matter.
     
201
  • single-acting / mechanical seal acc. to API 610
  • preassembled cartridge mechanical seal ready for installation
  • balanced
  • independent of direction of rotation
  • multiple springs (protected)
  • stationary design
 
Dimensions: 30-115 mm
(also in inches)
pmax: 70 bar (125bar)
t: -80C...+315C
(acc. to secondary seal)
vmax: 35 m/s
  Operation: API plan 11+53

Solid mechanical seal in stationary design with solid seal face/ stationary seats for sealing of crude oil as well as refinery and petrochemical finished products in pipeline pumps

Multipoint injection, seal face design for high p.v factor and further constructive measures produce an operationally safe mechanical seal with high service life (MTBR) with these applications.

Preferred materials: Q1U2VG1G1

API Code: BSTFO
      

   
  Quench oil pumps / ethylene plants
  Main quench oil pumps are the "heart" of an ethylene plant. Requirements to the mechanical seal concerning safety of operation and service life (MTBF/MTBR) are accordingly high.
Due to high shut-down and seal exchange costs, the mechanical seal must be designed as a "long-term seal".
     
861
  • double-acting / back-to-back
  • preassembled cartridge mechanical seal ready for installation
  • balanced
  • multiple springs (protected on the product side)
Dimensions: 70-200 mm
pmax: 50 bar
t: - 120C...315C
(acc. to secondary seal)
vmax: 35 m/s
 
Operation: API plan 53, pressure-superimposed, circulating barrier fluid quench - external vessel (s. key plan)

Overdimensioning of the most important sealing elements

flexible, self-aligning arrangement of seal faces/ stationary seats

Solid hard alloy seal faces in special seal face geometry; optimized barrier fluid flow

long-term mechanical seal; proved service life > 4 years in main quench oil pumps
     

   
  Hydrogenation processes / nitriles / fatty acids
  In catalytic hydrogenation processes the mechanical seals in process pumps have to meet highest demands of sealing technique. This is necessary due to the media to be sealed on the one hand and the type of process on the other: Nitriles are classified as detrimental to health; delivered hydrogen is explosive; the inserted metal catalyzers plate on all surfaces (even on seal faces) and are highly abrasive.

The operating conditions stipulate a change of pressure and temperature to a considerable degree in short cycles. The mechanical seal is designed to meet these requirements.
     
881
  • double-acting incl. auxiliary stuffing box
  • preassembled cartridge mechanical seal ready for installation
  • balanced
  • independent of direction of rotation
  • multiple springs
  • stationary design
Dimensions: 30-200 mm
(also in inches)
Techn. data (of this application):
Dimensions: (sd) 82 mm
p: 0 - 36 bar (50 bar)
t: 20C - 280C
v: 12 m/s (25 m/s)
 
  Operation: barrier pressure superposition / auxiliary flushing

Solid mechanical seal with safety reserves: mechanical seal outside the medium up to a max. of 150 bar and auxiliary stuffing box on the atmospheric side

guided circulation flow for optimal heat dissipation

excl. use of solid seal faces / stationary seats flexibly run on bearings

double pumping screw to assist barrier medium circulation

Materials (for this application): U2 U2 K G1 G1 + U2 Q2 V

Aggregate to be sealed: reactor circulation pump in hydrogenation / specific process pump with reinforced shaft and bearing
      

   
  Hot water
  For single-stage pumps with cantilevered rotor disk. Our concept for sealing of hot water up to a max. of 200C is to work without auxiliary cooling, to use a single-acting mechanical seal in stationary design, with rotating throttle bush and a quench fluid vessel/ thermosyphon.
     
208S
  • single-acting
  • preassembled cartridge mechanical seal ready for installation
  • independent of direction of rotation
  • multiple springs (protected)
  • stationary design
Dimensions: 28-75 mm
pmax: 25 bar
tmax: 200C
vmax: 25 m/s
 
  Material: AQ2EGG (altern. Q1Q1EGG)
Operation: "dead-end" with circulation via separate thermosyphon vessel

Assembly aids; solid gland with " connections (ZE/ZA); mechanical seal complete with rotating throttle bush.

Solid seal faces/ stationary seats, "self-aligning" arrangement.

Accessories: Thermosyphon vessel type 8L (6124-4)

Arrangement: acc. to key plan 7153-3/1.

The cessation of auxiliary cooling, which is often rather susceptible (e.g. to calcification of the cooling chamber) makes this concept rather economical. The service life is also usually much longer than with the conventional way of sealing.

Seal 208S for this kind of application is adapted to the resp. aggretate; there have been applications in KSB pumps, HPK, CPK, HDA, Etanorm; Sulzer-, Halberg-, TurboEgger and other pumps.

We also have successful solutions for hot water applications with multiple-stage pumps with double bearings. For inquiries refer to CHETRA.
     

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