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Flush port added to bellows seal
ISSN 1350-4789
An International Newsletter
M a r c h 1995
Sealing Technology
Contents Static s e a l i n g
1
• Asbestos-free gaskets for chlorine service
Dynamic sealing • • • •
Hush port added to bellows seal Compression packing for abrasive mediums Dura Seal handles high temperature services Elastomer bellows seal increases pump service life
General n e w s
4
• Seal face flatness is essential for proper operation and service life • DuPont and Dow to form elastomers business • Gasket centre to open in UK • Paper mill awards industry's largest mechanical seal order • Holography system designed for seal quality control • Plans for STLE 50th meeting announced • John Crane UK secures £400 000 order • Remote seals for pressure transmitters • Seals video available from FSA
Technology
!n~ight
7
• Non-contacting seals for critical service process pumps
Patents
12
• Shaft seal with controlled porosity elements • Method of manufacturing a composite seal • Turbine radial adjustable labyrinth seal
Events calendar
16
Number 15
A s b e s t o s - f r e e gaskets for c h l o r i n e service Permanite AF2200, a glass-based sheet seating material manufactured by TBA Sealing Materials Ltd, has been included in a test programme carried out by the USA Chlorine Institute. 13 different asbestos-free materials were evaluated for sealing gaseous and liquid chlorine; evaluations were carried out at four different chemical plants covering a range of temperature/ pressure combinations. There were two series of tests, one series took 6 months, the other 12 months. At the end of these tests a panel of users reviewed the 'evaluation sheets' completed by the four test centres and also examined the used gaskets. For each temperature:/pressure combination the panel gave the material a mark based on the following scale, as a comparison with the performance of compressed asbestos fibre (CAF): A: Improved performance B: Comparative performance C: Inferior but acceptable performance D: Inferior performance E: Unacceptable performance After the 6 months tests, 4 of the 13 materials were given B ratings, one of which was TBA Sealing Materials' Permanite AF 2200. After the 12 months tests, Permanite AF 2200 was the only material given a B ranking at all the temperature/pressure combinations used. Full details of this test programme are given in the 'Chlorine Institute Pamphlet 95' available from The Chlorine Institute Inc, 2001 L Street, NW Washington DC 20036, US&
Contact: TBA Industrial Products Ltd, PO Box 21, Rochdale, Lancs OL12 7EU, UK. Teh + 44 1706 715000; Fax: + 4 4 1706 46055.
•
&-
I'll. S l a V I I~l<
Flush p o r t a d d e d to b e l l o w s seal
TI'~( 11 NOI .()~; '(
A design change has been made to the general purpose cartridge mounted welded metal bellows seal, devel-
© 1 9 9 5 Elsevier Science Ltd., England./95/$7.00 per item No part of this publication may be reproduced, stored in a retrieval system, or transmitted by any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publishers. (Readers in the USA,please see special regulations listed on the back cover.)
Dynamic sealing oped by EG&G Sealol. The EZ-1 has recently been released with the addition of a flush port. The welded metal bellows seal has a 45 ° tilt angle which distributes the stress away from the I.D. welds of the bellows' plates through the sweep radius. The tilt angle, three sweep radius and nesting ripple plate design, give the bellows core rigidity and uniform stress distribution.
Compression packing for abrasive mediums
Key features of the EZ-1 include: • flush port: this allows circulation or introduction of fluid at the seal faces to provide lubrication or a cooling and/or cleansing action. It also provides a means of eliminating trapped air on vertical pump applications. • available with hard faces: these enable the sealing of abrasive applications. • unique self-centring, slide-on and tightening design. • glass-filled Teflon gland gasket is recessed in the gland: this prevents gasket blow-out and also retains the gasket in position. • glass-filled Teflon spacer (retaining ring): this allows easy start-ups and provides increased chemical compatibility. • compact design: the seal fits across narrow crosssection stuffing boxes, engineered to fit over 500 of the most c o m m o n pumps without modification. The EZ-I's performance capabilities are speeds up to 25 m/s, pressures from vacuum to 20 bar and temperatures from - 30 °C to + 200 °C.
Contact: EG&G Sealol, 50 Sharpe Drive, Cranston, RI 02920-4463, USA. Tel: + 1 401 463 5270; Fax: + 1 401 463 6820. Flush Port
tt~
Developed for contamination sensitive applications such as pulp and paper, and pharmaceuticals and food, SEQUEL, a white compression packing has recently been introduced by W L Gore & Associates. This packing material provides an alternative for Gore's GFO fibre, offering a lower thermal expansion coefficient than traditional PTFE packings as well as high thermal conductivity. During a r e c e n t evaluation of SEQUEL, Gore found that a particularly difficult food application is sealing the glands at the end of the paddle shafts of continuous conches w h i c h are used to blend cocoa, sugar and butter. Engineers at United Biscuits' McVities chocolate refinery in Stockport, UK, had b e e n using GFO packing; but because of colour, this packing regime was compromised by installing a ring of PTFE packing at either end of the gland, which meant that this configuration would sometimes only give as little as 12 weeks' service. When the n e w SEQUEL packing was introduced on site, it was decided to run a trial on just one conche. This time there was no need to use PTFE at each end and the packing lasted significantly longer. McVities has now standardized on SEQUEL packing for its continuous conches. A number of manufacturers have tested the packing, initially mainly on chocolate pumps. However, now SEQUEL is being adopted for a range of applications including agitators, pumps and conches. In a recent statement, Kemutec Group Ltd, manufacturer of the Tourell range of continuous conches, announced that it is to standardize on SEQUEL packing for future machines.
Contact: W L Gore & Associates (UK) Ltd, S e a l a n t Technologies Group, West Pitkerro Industrial Estate, Dundee, Tayside DD5 3RX, UK. Tel: + 44 1382 738 122; Fax; + 4 4 1382 480839.
Dura Seal handles high temperature services ~,. ~ v , ~ change-out
2
,u~~ ) .
Sih:oo Carbide)
~ Ring Sealide (Sinlered Silicor~Carb~))
Developed for high temperature services typically found in the petroleum industry, the PBR and PBS Dura Seal designs incorporate welded metal bellows construction
Sealing Technology No. 15
An International Newsletter
M a r c h 1995
Sealing Technology
Contents Static s e a l i n g
1
• Asbestos-free gaskets for chlorine service
Dynamic sealing • • • •
Hush port added to bellows seal Compression packing for abrasive mediums Dura Seal handles high temperature services Elastomer bellows seal increases pump service life
General n e w s
4
• Seal face flatness is essential for proper operation and service life • DuPont and Dow to form elastomers business • Gasket centre to open in UK • Paper mill awards industry's largest mechanical seal order • Holography system designed for seal quality control • Plans for STLE 50th meeting announced • John Crane UK secures £400 000 order • Remote seals for pressure transmitters • Seals video available from FSA
Technology
!n~ight
7
• Non-contacting seals for critical service process pumps
Patents
12
• Shaft seal with controlled porosity elements • Method of manufacturing a composite seal • Turbine radial adjustable labyrinth seal
Events calendar
16
Number 15
A s b e s t o s - f r e e gaskets for c h l o r i n e service Permanite AF2200, a glass-based sheet seating material manufactured by TBA Sealing Materials Ltd, has been included in a test programme carried out by the USA Chlorine Institute. 13 different asbestos-free materials were evaluated for sealing gaseous and liquid chlorine; evaluations were carried out at four different chemical plants covering a range of temperature/ pressure combinations. There were two series of tests, one series took 6 months, the other 12 months. At the end of these tests a panel of users reviewed the 'evaluation sheets' completed by the four test centres and also examined the used gaskets. For each temperature:/pressure combination the panel gave the material a mark based on the following scale, as a comparison with the performance of compressed asbestos fibre (CAF): A: Improved performance B: Comparative performance C: Inferior but acceptable performance D: Inferior performance E: Unacceptable performance After the 6 months tests, 4 of the 13 materials were given B ratings, one of which was TBA Sealing Materials' Permanite AF 2200. After the 12 months tests, Permanite AF 2200 was the only material given a B ranking at all the temperature/pressure combinations used. Full details of this test programme are given in the 'Chlorine Institute Pamphlet 95' available from The Chlorine Institute Inc, 2001 L Street, NW Washington DC 20036, US&
Contact: TBA Industrial Products Ltd, PO Box 21, Rochdale, Lancs OL12 7EU, UK. Teh + 44 1706 715000; Fax: + 4 4 1706 46055.
•
&-
I'll. S l a V I I~l<
Flush p o r t a d d e d to b e l l o w s seal
TI'~( 11 NOI .()~; '(
A design change has been made to the general purpose cartridge mounted welded metal bellows seal, devel-
© 1 9 9 5 Elsevier Science Ltd., England./95/$7.00 per item No part of this publication may be reproduced, stored in a retrieval system, or transmitted by any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publishers. (Readers in the USA,please see special regulations listed on the back cover.)
Dynamic sealing oped by EG&G Sealol. The EZ-1 has recently been released with the addition of a flush port. The welded metal bellows seal has a 45 ° tilt angle which distributes the stress away from the I.D. welds of the bellows' plates through the sweep radius. The tilt angle, three sweep radius and nesting ripple plate design, give the bellows core rigidity and uniform stress distribution.
Compression packing for abrasive mediums
Key features of the EZ-1 include: • flush port: this allows circulation or introduction of fluid at the seal faces to provide lubrication or a cooling and/or cleansing action. It also provides a means of eliminating trapped air on vertical pump applications. • available with hard faces: these enable the sealing of abrasive applications. • unique self-centring, slide-on and tightening design. • glass-filled Teflon gland gasket is recessed in the gland: this prevents gasket blow-out and also retains the gasket in position. • glass-filled Teflon spacer (retaining ring): this allows easy start-ups and provides increased chemical compatibility. • compact design: the seal fits across narrow crosssection stuffing boxes, engineered to fit over 500 of the most c o m m o n pumps without modification. The EZ-I's performance capabilities are speeds up to 25 m/s, pressures from vacuum to 20 bar and temperatures from - 30 °C to + 200 °C.
Contact: EG&G Sealol, 50 Sharpe Drive, Cranston, RI 02920-4463, USA. Tel: + 1 401 463 5270; Fax: + 1 401 463 6820. Flush Port
tt~
Developed for contamination sensitive applications such as pulp and paper, and pharmaceuticals and food, SEQUEL, a white compression packing has recently been introduced by W L Gore & Associates. This packing material provides an alternative for Gore's GFO fibre, offering a lower thermal expansion coefficient than traditional PTFE packings as well as high thermal conductivity. During a r e c e n t evaluation of SEQUEL, Gore found that a particularly difficult food application is sealing the glands at the end of the paddle shafts of continuous conches w h i c h are used to blend cocoa, sugar and butter. Engineers at United Biscuits' McVities chocolate refinery in Stockport, UK, had b e e n using GFO packing; but because of colour, this packing regime was compromised by installing a ring of PTFE packing at either end of the gland, which meant that this configuration would sometimes only give as little as 12 weeks' service. When the n e w SEQUEL packing was introduced on site, it was decided to run a trial on just one conche. This time there was no need to use PTFE at each end and the packing lasted significantly longer. McVities has now standardized on SEQUEL packing for its continuous conches. A number of manufacturers have tested the packing, initially mainly on chocolate pumps. However, now SEQUEL is being adopted for a range of applications including agitators, pumps and conches. In a recent statement, Kemutec Group Ltd, manufacturer of the Tourell range of continuous conches, announced that it is to standardize on SEQUEL packing for future machines.
Contact: W L Gore & Associates (UK) Ltd, S e a l a n t Technologies Group, West Pitkerro Industrial Estate, Dundee, Tayside DD5 3RX, UK. Tel: + 44 1382 738 122; Fax; + 4 4 1382 480839.
Dura Seal handles high temperature services ~,. ~ v , ~ change-out
2
,u~~ ) .
Sih:oo Carbide)
~ Ring Sealide (Sinlered Silicor~Carb~))
Developed for high temperature services typically found in the petroleum industry, the PBR and PBS Dura Seal designs incorporate welded metal bellows construction
Sealing Technology No. 15