3
Cartex’” 0 improve sed life cartridge seals reliability and Robustness is an important requirement for fluid sealing in the diverse range of environments encountered in industry today. As we reported in the last issue, the ongoing development, deployment and acceptance of materials play a key role in this respect. The field is continually moving forwards as new materials - or new forms of existing ones - appear as commercial products. Each must exhibit a considerable advantage over existing solutions. Tradition is institutionalized in the sealing industry, but with the market only creeping forwards a few points over the past year, companies have to try extra hard to just hold their position, never mind assuage their shareholders with good profit margins. To illustrate the point, in this issue we highlight a global player whose products are the choice for many industry specifiers: Burgmann GmbH, based in Wolfratshausen, near Munich in southern Germany. Recently in the news was the announcement that Ineos Chlor Ltd had ‘dramatically reduced pump maintenance costs and seal spares inventory’ at its UK sites. This was achieved through a seal contract with Burgmann (UK) Ltd. This is one example of how today’s fluid sealing products companies are tackling the challenges of the modern marketplace. In fact, despite tough competition and the enormous price pressure that presently characterises the international markets, Burgmann has been able to continue to show good progress by closing the fiscal year 2000 with positive figures. Moreover, its turnover was up 7.8% over that of the preceding year. Contract shows 30% reduction in costs In the above-mentioned deal with UK-based Ineos Chlor - which was formed in January to take over ICI’s Chlor-Chemicals business - the first year of the contract that covers the supply and repair of mechanical seals has shown a reduction of more than 30% in seal purchase and repair costs. This has in turn produced a substantial cost benefit in the overall pump repair costs, and provided improved pump availability to the process plants. Steve Moore, Ineos Chlor’s rotating equipment engineer, commented that, ‘Regular site visits by Burgmann engineers combined with a mutually agreed upgrade programme has provided us with the focused resources needed to lift pump and seal performance onto a new level of reliability. Seal and pump failures have dropped considerably during this year. We expect additional savings as the frequency of seal failures drops further over the next three years.’ Burgmann has combined the latest materials technology with best installation practice to ensure that all seals have the optimum chance for a long life under the typical operating conditions on-site. The next phase of the contract involves further development of the stock management programme introduced by Burgmann. This has already reduced the number of seal inventory items by more than 50%. It is anticipated that all seal stocks will eventually be under Burgmann control, to maximise seal rationalisation and provide Ineos Chlor with additional savings through the release of existing capital tied up in seal spares stock. Andy Faulkner, Ineos Chlor’s buying team leader, emphasises the success of the contract by saying, ‘Our first year savings have justified our decision to dramatically change our purchasing methods for key products. Burgmann has performed so well as a supply partner that we have extended the contract to four years.’ longer seal life Burgmann provides an example of the route to take to ensure continued market success with d new product launches. Its Cartexm cartridge seals combine extended performance margins with greater reliability and longer seal life, while the PDGS elastomer-free compressor seal is for high-pressure and low-temperature applications. The new line of Cartex cartridge seals (Figure 1) features a robust design with heavy- duty components so that they are more tolerant of system upsets and installation errors. Consequently, these seals are claimed to provide greater reliability and longer seal life than competitive seal designs. Single, double and gas-barrier seals are all available in the new line. All Cartex seals feature interchangeable components for reduced inven- tory costs and fast, economical service. They come in standard and large-bore configurations, which reduces the need for seal chamber modifications. Cartex gas barrier seals are bidirectional, and can accommodate solids loadings as high as 3%. They fit most ANSI seal chambers without modifications, provide zero product emissions, eliminate seal face wear, and reduce energy consumption. They are available in sizes ranging from 1.125 to 4 inches (28 to 100 mm). Double wet Cartex seals are available in both dual and tandem configurations. The single seals are offered with or without a pressure-less fluid quench feature, which contains the process liquid and directs it to a defined location in the event of primary seal failure. The single and double wet seals are available in sizes ranging from 1 to 4 inches (25 to 100 mm). The company says that Cartex seals offer a number of performance advantages. Spring- loaded stationary faces compensate for angular misalignment of the shaft and box face, providing a low leakage rate under less than ideal conditions. Monolithic seal faces reduce seal face distortion for minimal leakage and more reliable operation. Springs and pins are isolated from the product side, so the springs are not corroded and seal life is extended. The robust cartridge design stabilizes the seal gap for more reliable seal Sealing Technology No. 92 @

CarterTM cartridge seals improve reliability and seal life

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Page 1: CarterTM cartridge seals improve reliability and seal life

Cartex’” 0

improve sed life

cartridge seals reliability and

Robustness is an important requirement for fluid sealing in the diverse range of

environments encountered in industry today. As we reported in the last issue, the

ongoing development, deployment and acceptance of materials play a key role in

this respect. The field is continually moving forwards as new materials - or new

forms of existing ones - appear as commercial products. Each must exhibit a

considerable advantage over existing solutions. Tradition is institutionalized in

the sealing industry, but with the market only creeping forwards a few points

over the past year, companies have to try extra hard to just hold their position,

never mind assuage their shareholders with good profit margins. To illustrate the

point, in this issue we highlight a global player whose products are the choice for

many industry specifiers: Burgmann GmbH, based in Wolfratshausen, near

Munich in southern Germany.

Recently in the news was the announcement that

Ineos Chlor Ltd had ‘dramatically reduced pump

maintenance costs and seal spares inventory’ at

its UK sites. This was achieved through a seal

contract with Burgmann (UK) Ltd.

This is one example of how today’s fluid sealing

products companies are tackling the challenges of

the modern marketplace. In fact, despite tough

competition and the enormous price pressure that

presently characterises the international markets,

Burgmann has been able to continue to show

good progress by closing the fiscal year 2000 with

positive figures. Moreover, its turnover was up

7.8% over that of the preceding year.

Contract shows 30% reduction in costs In the above-mentioned deal with UK-based

Ineos Chlor - which was formed in January to

take over ICI’s Chlor-Chemicals business - the

first year of the contract that covers the supply

and repair of mechanical seals has shown a

reduction of more than 30% in seal purchase

and repair costs. This has in turn produced a

substantial cost benefit in the overall pump

repair costs, and provided improved pump

availability to the process plants.

Steve Moore, Ineos Chlor’s rotating equipment

engineer, commented that, ‘Regular site visits by

Burgmann engineers combined with a mutually

agreed upgrade programme has provided us with

the focused resources needed to lift pump and seal

performance onto a new level of reliability. Seal

and pump failures have dropped considerably

during this year. We expect additional savings as

the frequency of seal failures drops further over

the next three years.’

Burgmann has combined the latest materials

technology with best installation practice to ensure

that all seals have the optimum chance for a long

life under the typical operating conditions on-site.

The next phase of the contract involves further

development of the stock management programme

introduced by Burgmann. This has already reduced

the number of seal inventory items by more than

50%. It is anticipated that all seal stocks will

eventually be under Burgmann control, to

maximise seal rationalisation and provide Ineos

Chlor with additional savings through the release of

existing capital tied up in seal spares stock.

Andy Faulkner, Ineos Chlor’s buying team

leader, emphasises the success of the contract by

saying, ‘Our first year savings have justified our

decision to dramatically change our purchasing

methods for key products. Burgmann has

performed so well as a supply partner that we

have extended the contract to four years.’

longer seal life Burgmann provides an example of the route to

take to ensure continued market success with

d

new product launches. Its Cartexm cartridge

seals combine extended performance margins

with greater reliability and longer seal life, while

the PDGS elastomer-free compressor seal is for

high-pressure and low-temperature applications.

The new line of Cartex cartridge seals

(Figure 1) features a robust design with heavy-

duty components so that they are more tolerant

of system upsets and installation errors.

Consequently, these seals are claimed to provide

greater reliability and longer seal life than

competitive seal designs.

Single, double and gas-barrier seals are all

available in the new line. All Cartex seals feature

interchangeable components for reduced inven-

tory costs and fast, economical service. They come

in standard and large-bore configurations, which

reduces the need for seal chamber modifications.

Cartex gas barrier seals are bidirectional, and

can accommodate solids loadings as high as 3%.

They fit most ANSI seal chambers without

modifications, provide zero product emissions,

eliminate seal face wear, and reduce energy

consumption. They are available in sizes ranging

from 1.125 to 4 inches (28 to 100 mm).

Double wet Cartex seals are available in both

dual and tandem configurations. The single seals

are offered with or without a pressure-less fluid

quench feature, which contains the process

liquid and directs it to a defined location in the

event of primary seal failure. The single and

double wet seals are available in sizes ranging

from 1 to 4 inches (25 to 100 mm).

The company says that Cartex seals offer a

number of performance advantages. Spring-

loaded stationary faces compensate for angular

misalignment of the shaft and box face,

providing a low leakage rate under less than ideal

conditions. Monolithic seal faces reduce seal face

distortion for minimal leakage and more reliable

operation. Springs and pins are isolated from the

product side, so the springs are not corroded and

seal life is extended. The robust cartridge design

stabilizes the seal gap for more reliable seal

Sealing Technology No. 92 @

Page 2: CarterTM cartridge seals improve reliability and seal life

performance and longer seal life. Furthermore,

the O-rings are located on the external side,

eliminating seal hang-up and improving solids

handling capabilities.

The operating temperature range for single

and double wet Cartex seals is from -40 to

428°F (-40 to 22o”C), and the pressure limit is

360 psi (25 bar), depending on materials. The

operating temperature range for the gas seals is

from -5 to 428°F (-20 to 220”(Z), and the

operating pressure limit is 190 psi (13

Meeting extreme conditions The new elastomer-free, gas-lubricated mech-

anical seal from Burgmann was specially deve-

loped for extreme requirements in high-pressure

and low-temperature applications in compressors.

The PDGS seal’s operation and broad range of

apphcation have been intensively tested in

applications-related trials and test runs. A universal

pressure operating range from 1 to 350 bara is the

result. Stable leakage rates and reliable operating

characteristics are displayed by the PDGS in all

operating ranges. Excellent mobility of the

purpose-developed dynamic secondary seals is

typical in low-temperature duty. In meeting all

requirements such as automatic alignment and

resistance to extrusion, temperature and chemicals,

the seals have exactly those attributes which give

the compressor seal a high level of operational

reliability, says Burgmann.

Design features for this fluid sealing product

include:

.

.

Secondary seals made from a spring-

reinforced special compound with excellent

resistance to chemicals (equivalent to PTFE).

No explosive decompression.

Back-up ring and balancing sleeve of the

dynamic secondary seals made of tungsten

carbide for zero radial shrinkage, a small

controlled extrusion gap, and optimized

sliding properties of the secondary seals

without ‘catching’.

Optimized aerodynamic gas grooves,

optimal sliding properties during start-up,

and maximal rigidity of the gas film (also

pressureless).

No baffle edge in the flow direction, for a

self-cleaning effect.

Ceramic-compatible design with friction-

locked torque transmission of the rotating

seat, and no increase in stresses by shaping

operations.

Diamond-like carbon (DLC) coating of the

seal faces.

Operating limits:

l Shaft diameter from 25 to 320 mm.

l Operating pressure from 1 to 350 bara.

l Operating temperature range from -170 to

230°C.

l Sliding velocity of 200 m/s.

Turning to the web Burgmann recently joined the wave of companies

turning to web-based tools to help their

customers to select the best fluid sealing solution

for their particular application. Given the

diversity of availabilities, the web is proving a very

useful tool for suppliers and customers alike. It

was Burgmann’s intent when setting up CASS -

its online Computer Aided Seal Selection facility

- to make it as easy as possible to find the correct

seal for specific application requirements. Users

just have to select the medium to be sealed and

other operating conditions.

CASS provides all seal types recommended

for the chosen application, as well as inform-

ation on their use. For mechanical seals, even

material combinations, specific use and a seal

drawing with all measures necessary for

installation are provided. The user either selects

the medium first, or proceeds directly to the

selection of seal.

Replacing the German standard, DIN 24960 As part of the harmonisation process under way

in the European standardisation system, the new

standard EN 12756 (December 2000) has

appeared in the field of mechanical seals. It

replaces the German standard, DIN 24960, and

the French standard, NF E29-99 1.

Burgmann says that, as with other companies,

the conversion affects all of its standard

mechanical seals. These seals can easily be

recognized by the letter ‘N’ in their designation

and the drawing number. The seal type

HRC...N represents an exception to this, as it

will initially continue to be made in accordance

with the DIN 24960 standard (C).

Depending on the aggregate, method of

operation, environmental requirements etc.,

mechanical seals require additional special

equipment which ensures their perfect

functioning. Such equipment includes quench

fluid vessels, thermosiphon vessels with various

components, buffer pressure units, buffer gas

systems, refill units, heat-exchangers and

magnetic filters. In addition to standard systems,

Burgmann also supplies custom-made supply

systems for complex applications.

The EN is published by the European

standardisation body CEN (Comite Europeen

de Normalisation) in Brussels, Belgium. EN

12756 is entitled ‘Mechanical seals - Principal

dimensions, designation and material codes’,

and exists in three official versions (English,

French and German). The European standard

will be given the status of a national standard,

either by endorsement or by publication of an

@a Sealing Technology No. 92

Page 3: CarterTM cartridge seals improve reliability and seal life

identical text. In Germany, this has been done

by the publication of the DIN EN 12756

standard (March 2001).

EN 12756 contains the principal

dimensions for the internal installation of

single and multiple mechanical seals with

(rotating) spring units into the pump sealing

cavity, according to IS0 3069 (-S) as

minimum cavity dimensions as typical for

centrifugal pumps in accordance with EN

22858 and EN 733. It also gives the seal

designations and material codes to be used.

In relation to DIN 24960 (June 1992

edition), the dimensions for possible coatings in

the area of adjacent seals and the specification

for configuration of the mechanical seal with a

stationary spring unit (version C), have been

deleted.

Continued success in 2000 As we mentioned at the beginning of this article,

Burgmann’s financial results - while perhaps an

exception, rather than the rule - show that in

some sectors of the industry the market is doing

well enough. The company’s consolidated group

sales rose to more than EUR241 million

(US$205 million) in 2000, approximately 65%

of which was earned through group operations

Patents This issue’s sealing patent coverage is again a

cosmopolitan &air - new patents from

Germany, Japan, Sweden and the US. It

includes sealing inventions with a diversity of

mechanical themes, from spark plugs to

refrigeration, from cellphones to cabling.

From 3M comes an improvement in the

splicing of cables. As with many seals, the

objective is protection from water and other

vapours to prevent corrosion or a short

circuit. The common solution is a splice case

replete with end seals, but the many different

designs and configurations have one common

disadvantage: they are cumbersome and time-

consuming when adding or removing a cable.

3M offers a response to the need for a

segmented end seal in which the segments can

be easily attached to, and removed from, the

support body with a minimum of additional

hardware, yet which can be adapted to

provide a desired (for example, even) pressure

distribution across a particular segment.

In automotive engines, we have previously

covered head gaskets, but this time we describe

sealing a spark plug gasket. From Beru AG in

Germany, it relates to a process for sealing of the

terminal-side end area of the glow tube of a glow

outside Germany - 2% more than in the

preceding year. The remaining 35% was earned

in Germany, where sales rose to EUR84.2

million ($71.7 million) against EUR78.7

million for the previous year. Sales outside

Germany increased to EURl57.4m ($134

million) versus EUR136.3 million the previous

year. The group currently employs a workforce

of 2,890 worldwide.

The first quarter of 2001 has reflected a

similarly positive trend, so that the seal

manufacturing group anticipates satisfactory

increases in sales and operating results by the

end of the year. However, in spite of the positive

figures achieved to date, the continuing difficult

situation in the international trading areas will

call for unbroken commitment, creativity and

motivation on the part of staff throughout the

group. As well as product characteristics, the

quality of service provided by manufacturers is

constantly gaining importance. For this reason

the existing sales and marketing organization -

in particular the service structure - is being

strengthened even further worldwide, with the

local availability of supplies and qualified service

as key priorities. On a joint basis and as partner,

Burgmann will be developing service packages

and customized service concepts aimed at

plug. All too often, undesirable failures occur

and manufacturing costs can be large, so the

objective of the invention is to provide for mass

production of glow plugs.

The gasket patent for sealing a refrigerant

compressor, by H. Ikeda et al. from Japan,

describes fluid-tight, stable and good sealing as

well as a boundary portion between high- and

low-pressure regions within the compressor. It

uses an innovative design, using ‘trifurcatedly

interconnected’ (i.e. by three arms) ridges on the

outer and inner sealing portions of the gasket.

This enables the gasket to be in face contact

with the sealed portions, thereby exhibiting a

good sealing function with a high stability.

Finally, from Sweden, one of the world’s

centres for the manufacture of mobile phones,

comes a description of a slowly expanding

gasket. Gaskets in cellphones full?1 several

functions - acoustic sealing, preventing dust

ingress etc. Today’s gaskets use soft elastic foam

plastic, and sealing is obtained when the gasket

is compressed. To achieve efficient sealing the

compression of the gasket must be as large as

possible, ie. the uncompressed gasket must have

a considerable thickness in order to obtain a

tight sealing in its compressed state. This is not

ideal from a manufacturing viewpoint, so this

invention instead uses a slowly expanding

cellular plastic pre-compressed before assembly

optimizing existing technology and reducing

maintenance costs, the objective being the

conclusion of long-term service agreements

from which both company and its customers

benefit. The group can currently call on

experience gained from around 80 international

service agreements.

At the same time, the German-based seal

manufacturer will continue to place particular

emphasis on research and development in all its

product areas to consolidate and build on its

position at the head of the sealing technology

field. In doing so, Burgmann will be making full

and optimum use of all resources such as

product innovation, globalization and comm-

unications technology in the face of increasingly

fierce competition for customers.

For more information, contad: Burgmann

Dichtungswerke GmbH & Co KG, AuBere Sauedacher

StraBe 8-l 0, D-B2502 Wolfratshausen, Germany. Tel:

+49 8171 23-O. Fax: +49 8171 23-1214, Email:

[email protected], http://wwwburgmann.com

Or contact: lneos Chlor Ltd, PO 80x 14, The Heath,

Runcorn, Cheshire WA7 4QG, UK. Tel: +44 1928

511050, Fax: +44 1928 581072, Email:

general_info@ineoschlorcom,

http://www.ineoschlor.com

Sealing Technology No. 92 0

of the phone. In this way the installation of the

gasket material can be greatly enhanced by pre-

compressing the gasket prior to installation.

Segmented end seals for cable splice case

EtIe: Segmented end seaI for a dosure such

as a splice case

Patent number: US 6248953

Date: 19 June 2001

Inventor: James IL Miier

Assignee 3M Innovative Properties Co, St

Paul, MN, USA

This invention provides a segmented end seal in

which the segments interlock with the support

structure, so that only a single fastener is needed

to fix a given segment to the support structure.

This result is achieved by providing the

segments with tabs that are inserted into notches

located in the support structure. The tabs are

oriented with respect to one another such that

they must be inserted and removed from the

notches in a particular sequence.

Typically, the tabs are oriented to provide an

even distribution of pressure across the segment,