METAL BELLOWS CARTRIDGE SEAL. Operating Conditions

Transcription

1 S--E Applications The Type is a metal bellows cartridge seal with computer optimised asymmetric bellows. General industrial applications including chemical processing, mining, pulp and paper and wastewater treatment. Used in areas where hygiene and purity are essential such as food, beverage, biotechnology and pharmaceutical industries. The even stress distribution in the bellows and the smooth profile lead to greater reliability, whilst the cartridge arrangement makes pump conversion and maintenance procedures faster and more reliable. For easy installation and maintenance, the slotted gland plate has an integral throttle bush and connections for seal flush, quench and drain. Available in Metric and Inch sizes to suit popular DIN and ANSI pumps without modification. Operating Conditions Temperatures: -4 C to +2 C/ -4 F to +39 F depending on materials used Pressures: Up to 2 bar g/ 29 psig Speed: Fluids Abrasives Aqueous Solutions Caustics Lubricants Slurries Chemicals Up to 25 m/s/ 5 fpm METRIC AND INCH RANGE

2 Design Features Asymmetric Formed Metal Bellows Results in even stress distribution, greater strength, higher flexibility and longer seal life. Throttle Bush Fitted as Standard Optional lipseal for containment of liquid quench media. Smooth Profile Smooth, open bellows profile is ideal for slurries and fibrous liquids. Simple Setting and Drive Mechanism Setting ring eliminates requirement for removable setting clips. Easily converted to indirect drive when grubscrew contact on the shaft/sleeve is unacceptable.

3 Type Typical Arrangement/Dimensional Data ØD4 ØD3 ØD3 L42 L L56 L39 THROTTLE BUSH (STANDARD) ØD26 ØD ØD95 MAX. D27 MIN. P.C.D. ØD94 MAX. Minimum fixing bolt P.C.D. D27 and slot width D28 are sized to suit stud or bolt diameters according to the seal size code, as shown below: 24 to 32 M1 or 3 8in. 33 to 48 M12 or 1 2in. 5 to 8 M16 or 5 8in. 825 to 116 M2 or 3 4in. D95 is the maximum distance between the bottom of opposing slots. BREAK EDGE 1mm RADIUS 2.5mm 1 For ease of installation, the lead-in edge of the shaft or sleeve should be chamfered as shown. Chart 1. Type Metric Range (mm) Seal Size Seal Size D4 (mm) Code D D3 Min. Max. D26 D27 D28 D3 D94 D95 L15 L39 L42 L

4 Type Typical Arrangement/Dimensional Data L42 L L56 L39 SEAT O-RING QUENCH/DRAIN D28 FLUSH ØD4 ØD3 ØD3 ØD26 Chart 2. Type Inch Range (mm) ØD±.5 Seal Size Seal Size D4 (Inches) Code D D3 Min. Max. D26 D27 D28 D3 D94 D95 L15 L39 L42 L Chart 3. Pressure/Velocity (PV) Limits BJ SEAT Alternative seat arrangement. QUENCH/DRAIN Positions of quench or drain connections (indicated by double arrows), and flush connection (indicated by single arrows). Thread sizes are related to seal size codes, as follows: 24 to in. NPT 666 to in. NPT Pressure (bar g) rpm Pressure (psig) 35 Direct Drive 3 rpm rpm Indirect Drive 2 36 rpm 15 Carbon Graphite or Silicon Carbide Coated Graphite v. Silicon Carbide Seal Size (mm) 4 (inches) Direct drive or indirect drive are inherent options on all Type cartridge seals, and the seals may be fitted using either method of drive: refer to the Type Instruction Manual, I- -E. To determine the maximum pressure for the size of Type seal required for indirect drive applications, use the thin graph line of Chart 3 to find the limit, and then check the appropriate multiplier factors given in Chart 5. If any factors of less than 1. are involved, the normal direct drive PV limit must be calculated and the lower of the two limits used. To determine the maximum pressure for the size of Type seal required for direct applications, multiply the pressure obtained from the upper graph line of this chart by the appropriate factors given in Chart 5 refer to the example.

5 Chart 4. Multiplier Factors Selection Considerations Multiplier Factor Sealed Fluid Petrol, Kerosene or better x 1. Lubricity Water, Aqueous Solutions, x 1.* Lighter Hydrocarbons (s.g..65), etc. x.75** Face and Seat Carbon Graphite or Silicon Carbide Coated Graphite Materials v. Silicon Carbide x 1. Carbon Graphite v. Aluminium Oxide x.6 Sealed Fluid 2 C/39 F and below x 1. Temperature Speed 36 rpm and below x 1. * Seal size codes up to and including 65mm/2.625in. ** Seal size codes above 65mm/2.625in. Example for Determining PV Limits: Seal: 8mm diameter Type Product: Water Face and seat material: Carbon graphite v. silicon carbide Operating temperature: 3 C/85 F Operating speed: 36 rpm Using Chart 3, the maximum pressure would be 19. bar g/276 psig. From Chart 5, apply the multiplier factors for the specific service requirements: 19. bar g/276 psig x.75 x 1. x 1. x 1. = bar g/27 psig. Therefore, for the example given, the maximum operating pressure is bar g/27 psig. Chart 5. Secondary Seal/Seat Ring Temperature Limits Material Temperature ( C) Medium Nitrile Fluorocarbon Ethylene Propylene* Perfluoroelastomer Medium Nitrile (F.D.A.)** Ethylene Propylene (F.D.A.)* Pure PTFE Glass Filled PTFE 4 C to +1 C/ 4 F to +21 F 3 C to +2 C/ 2 F to +39 F 4 C to +135 C/ 4 F to +275 F 2 C to +2 C/ 5 F to +39 F 4 C to +1 C/ 4 F to +21 F 4 C to +135 C/ 4 F to +275 F 2 C to +18 C/ 5 F to +355 F 4 C to +2 C/ 4 F to +39 F * Not to be used for hydrocarbons or mineral oils. ** Can withstand repeated steam sterilisation at +12 C/25 F without adverse effect. *** Although rated for lower temperatures, material should be limited to -4 C/-4 F in this seal. ( F) For hydrocarbon duties the limit is +12 C/25 F. For water duties the temperature should not exceed +135 C/275 F. Although rated to a higher temperature, material should be limited to +2 C/39 F in this seal. For water/steam duties the limit is +15 C/3 F. Chart 6. Criteria for Installation Chart 7. Recommendation for Viscous Fluids Shaft/Sleeve Surface Finish Ovality/ Out of Roundness End Play/ Axial Float Allowance Limits.2 to 1.2 µm Ra Fine Machined.5 mm/.2 in..8 mm/.3 in. F.I.M. Housing Squareness to Shaft See Chart 1. Standard Standard Seal Standard Seat, Refer to Seal and Pinned or with Hard Face John and Seat Clamped Seat and Pinned or Crane* Clamped Hard Seat Fluid Viscosity to to 1 1 to 35 Above (cst) 35 Max. Shaft Velocity (m/s) * Min.Radial Seal Std. 5 1 Clearance(mm) Heating at Start Up Optional Recommended cst = Kinematic Viscosity Centistokes (cst x 4.62 = SSU) SSU = Saybolt Seconds Universal

6 Chart 8. Hydrostatic Pressure Limits Pressure (bar g) Pressure (psig) Direct Drive Indirect Drive (mm) Chart 9. Housing Squareness to Shaft Axial Run-Out (mm) F.I.M.* Axial Run-Out (inches) F.I.M.* (mm) (inches) Seal Size *F.I.M. = Full Indicator Movement Seal Size Chart 1. Material Availability 4. (inches) ) SEAL COMPONENTS MATERIALS Description Standard Optional Seal Unit Bellows Inconel Alloy 718 Assembly Support Ring/Sleeve FV 52BPH Stainless Steel Primary Ring/Face Resin Impregnated Carbon Graphite Silicon Carbide Coated Graphite Secondary Seal O-Ring Nitrile Perfluoroelastomer Seat O-Ring Ethylene Propylene Nitrile BJ Seat Fluorocarbon Ethylene Propylene Seat Ring Pure PTFE BK Seat Glass Filled PTFE Gasket Compressed Fibre Centralising Ring Pure PTFE Gland Plate Assembly 316 Stainless Steel Drive Collar Snap Ring Set Screws Blanking Plugs BK Seat (Standard) Sintered Silicon Carbide BJ Seat (Optional) 99.5% Aluminium Oxide Ceramic Throttle Bush (Standard) Phosphor Bronze Lip Seal (Optional) Elastomer - Based PTFE - Based Material complies with The USA Federal Drug Administration (F.D.A.) Title 21 Paragraph Use material according to quench medium: elastomer-based for grease or oil; PTFE-based for water. Lip seals will withstand internal pressure up to 1 bar g/15 psig. Inconel is the trademark of Cabot Corp. John Crane Mechanical Seals Engineered Sealing Systems North America Morton Grove, Illinois USA Latin America Mexico City, Mexico Europe, Middle East, Africa Slough, UK Asia Pacific Singapore Tel: Fax: SEALING Tel: Fax: Tel: Fax: Tel: Fax: If the products featured will be used in a potentially dangerous and/or hazardous process, your John Crane representative should be consulted prior to their selection and use. In the interest of continuous development, John Crane Companies reserve the right to alter designs and specifications without prior notice. It is dangerous to smoke whilst handling products made from PTFE. Old and new PTFE products must not be incinerated John Crane Mechanical Seals Print 1/97 Web Site: ISO 91 Certified