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Leak-proof seal for polymer extraction pumps
Dynamic sealing
Leak-proof seal for polymer extraction pumps Vacuseal is a new design of viscous seal that provides positive sealing for gear pumps used in vacuum applications. It has no moving parts - the seal is created by a stagnant area of molten polymer - and protects against both leakage and air entrainment. The seal has been developed by LCI Corporation. The seal directs polymer from the higher pressure discharge side of the pump to two opposing spiral groove sections in the inside surface (surrounding the shaft) of the seal. Shaft rotation forces the two polymer flows toward each other. They meet in a buffer area, creating static containment of material which forms a viscous seal around the shaft. To provide a pathway for polymer from the discharge side of the pump, two simple modifications are required; a hole drilled into the body and a groove milled into the endplate. The seal is available in a wide variety of materials and provides sealing for viscosities from 75 000 to 20 000 000 cp. A water-cooled version is available for lower viscosity applications. It can operate at seal pressures from absolute vacuum to 3000 psig. A transducer can be supplied for monitoring pressure in the buffer zone. This can be helpful during start-ups. The main benefits of the seal are said to be that the seal has no moving or wear parts and it eliminates a mechanical seal buffer fluid system. The Vacuseal can be retrofitted in the field and no regular maintenance is required.
Contact: LCI Corporation, Fluid Systems Division, PO Box 16348, Charlotte, NC 28297-6348, USA. Tel: + 1 704 394 8341; Fax: + 1 704 393 8590.
Variable magnetic seal t e c h n o l o g y The use of magnetic sealing devices has been around for many years. However, due to the lack of stronger magnetic materials on the market only solid magnetic rings were used. The arrival of stronger materials enabling larger air gaps and the usage of individual magnets made it possible to vary the strength of the magnetic force, hence the name tWariable Magnetic Seal". A patented design using round magnets inserted into a non-magnetic carrier is the basis of variable magnetic seal technology developed by Norman Technology Inc. The seal head or the mating ring can be made from any of these non-magnetic materials; carbon, brass, stainless, plastics, rubber and alumirtium, against a carbon steel ring. In high speed applications where other O-rings are used to drive the magnets and later tend to slip, the "NTI" variable magnetic seal is provided with a positive drive. The components are light-weight and require no shielding.
Contact: N o r m a n T e c h n o l o g y Inc, 1120 D o n a l r e Way, Pacific Palisades, CA 90272-2222, USA. Tel: + I 310 459 3100; Fax: + 1 310 459 7600.
Double cartridge seal for severe applications A double cartridge seal for severe applications including those found in evaporation and causticizing plants, handling toxic, environmentally hazardous, abrasive and effluent liquids has been launched. The SB2A seal can be used in major process equipment including pumps, agitators, and mixers.
Table 1. Specifications for the SB2A double cartridge seal Technical specifications Materials Stuffing box pressure 20 bar (290 Psi ) max Seal faces: Barrier fluid pressure 15 bar (215 Psi) max Velocity 20 m/s (65 ft/s) max O-rings: Temperature 180 °C (350 °F ) max Metallurgy: Sprinss:
Sealing Technology No. 4
SiC Vs. SiC (product side) SiC vs. C (atm.side) PTFE against the product EPDM optional Viton optional, etc. AISI 329 standard Titanium, alloy 20, Hastelloy Nimonic steel
3
Leak-proof seal for polymer extraction pumps Vacuseal is a new design of viscous seal that provides positive sealing for gear pumps used in vacuum applications. It has no moving parts - the seal is created by a stagnant area of molten polymer - and protects against both leakage and air entrainment. The seal has been developed by LCI Corporation. The seal directs polymer from the higher pressure discharge side of the pump to two opposing spiral groove sections in the inside surface (surrounding the shaft) of the seal. Shaft rotation forces the two polymer flows toward each other. They meet in a buffer area, creating static containment of material which forms a viscous seal around the shaft. To provide a pathway for polymer from the discharge side of the pump, two simple modifications are required; a hole drilled into the body and a groove milled into the endplate. The seal is available in a wide variety of materials and provides sealing for viscosities from 75 000 to 20 000 000 cp. A water-cooled version is available for lower viscosity applications. It can operate at seal pressures from absolute vacuum to 3000 psig. A transducer can be supplied for monitoring pressure in the buffer zone. This can be helpful during start-ups. The main benefits of the seal are said to be that the seal has no moving or wear parts and it eliminates a mechanical seal buffer fluid system. The Vacuseal can be retrofitted in the field and no regular maintenance is required.
Contact: LCI Corporation, Fluid Systems Division, PO Box 16348, Charlotte, NC 28297-6348, USA. Tel: + 1 704 394 8341; Fax: + 1 704 393 8590.
Variable magnetic seal t e c h n o l o g y The use of magnetic sealing devices has been around for many years. However, due to the lack of stronger magnetic materials on the market only solid magnetic rings were used. The arrival of stronger materials enabling larger air gaps and the usage of individual magnets made it possible to vary the strength of the magnetic force, hence the name tWariable Magnetic Seal". A patented design using round magnets inserted into a non-magnetic carrier is the basis of variable magnetic seal technology developed by Norman Technology Inc. The seal head or the mating ring can be made from any of these non-magnetic materials; carbon, brass, stainless, plastics, rubber and alumirtium, against a carbon steel ring. In high speed applications where other O-rings are used to drive the magnets and later tend to slip, the "NTI" variable magnetic seal is provided with a positive drive. The components are light-weight and require no shielding.
Contact: N o r m a n T e c h n o l o g y Inc, 1120 D o n a l r e Way, Pacific Palisades, CA 90272-2222, USA. Tel: + I 310 459 3100; Fax: + 1 310 459 7600.
Double cartridge seal for severe applications A double cartridge seal for severe applications including those found in evaporation and causticizing plants, handling toxic, environmentally hazardous, abrasive and effluent liquids has been launched. The SB2A seal can be used in major process equipment including pumps, agitators, and mixers.
Table 1. Specifications for the SB2A double cartridge seal Technical specifications Materials Stuffing box pressure 20 bar (290 Psi ) max Seal faces: Barrier fluid pressure 15 bar (215 Psi) max Velocity 20 m/s (65 ft/s) max O-rings: Temperature 180 °C (350 °F ) max Metallurgy: Sprinss:
Sealing Technology No. 4
SiC Vs. SiC (product side) SiC vs. C (atm.side) PTFE against the product EPDM optional Viton optional, etc. AISI 329 standard Titanium, alloy 20, Hastelloy Nimonic steel
3