Field of the Invention
This invention relates to mechanical seals, which are fitted to rotating equipment in
virtually all types of industries.
A mechanical seal comprises a "floating" component which is mounted axially
movably around the rotary shaft of. for example, a pump and a "static" component
which is axially fixed, typically being secured to a housing. The floating component
has a flat annular end face. i.e. its seal face, directed towards a complementary seal
face of the static component. The floating component is urged towards the static
component to close the seal faces together to form a sliding face seal, usually by
means of one or more spring members. In use. one of the floating and static
components rotates; this component is therefore referred to as the rotan component.
The other of the floating and static components does not rotate and is referred to as the
stationary component.
Those seals whose floating component is rotary are described as rotary seals. If the
floating component is stationary, the seal is referred to as a stationary seal.
If the sliding seal between the rotary and stationary components are assembled and
pre-set prior to despatch from the Mechanical seal manufacturing premises, the
industry terminology for this is "cartridge seal". If the rotary and stationary
components are despatched individually (unassembled) from the Mechanical seal
manufacturing premises, the industry terminology for this is "component seal".
Mechanical seals are used in all types of industries to seal a variety of different
process media and operating conditions. The general industry term which defines the
area adjacent to the process media is "inboard". The industry term which defines the
area adjacent to the atmospheric side is "outboard".

Like most industries, the mechanical seal industry is highly competitive.
As a result, mechanical seal manufacturers constantly seek methods of improving
competitive advantage.
Background to the Invention
Pressed and formed components are one way in which mechanical seal manufacturers
can reduce the manufacturing cost of said component.
Unfortunately pressed components can comprise the technical aspects of a single
component or said aspects of a combination of components working relative to each
other.
One such example of this is the drive mechanism between two components working
relative to each other.
As pressed components are manufactured from a given thickness of material, the cross
sectional area of the drive mechanism is traditionally thereby limited to a
multiplication of said thickness.
Pressed components are typically manufactured from sheet material, typically steel or
stainless steel with a material thickness of 0.2mm to 2.5mm. Typically however, most
mechanical seal components are pressed using 0.8mm to 1.2mm thick material.
Pressed components offer the advantage that, in most cases, subsequent machining
operations are not necessary.. This therefore reduces the manufacturing cost
considerably.
The disadvantage of using said pressed parts is the effective drive mechanism between
said parts.

Gilbert US 5.725,219 teaches a mechanical seal design whereby two pressed and
substantially thin components engage each other via intermeshing castellations. Said
castellations compromise of an open longitudinal end in each member and when
engaged with each other are intended to transmit the rotational drive between two
longitudinal spaced sealing points within the seal assembly.
In practice this design suffers from several drawbacks, namely;
The torsional forces acting on the interface surface between the two substantially
thin members which are mounted in a radially resilient member and subjected to
equipment vibration, is the equivalent to a person pressing two knife edges
together whilst on a rowing boat in the sea in the middle of a storm. In practice,
said thin members radially misalign and rotationally twist inside of each other,
thereby negating and substantial rotational drive benefit between the two
members.
The longitudinally open ended castellations have sharp edges corners, given the
substantially thin material and their perpendicular position to the longitudinal end
of each member. Said sharp edges corners not only damage the substantially
resilient/rubber like sealing member but often damage/cut operators hands during
installation of the seal onto the equipment.
In the seals longitudinally uncompressed state, the open ended longitudinal
castellations of each member can disengage creating an installation issue.
Furthermore, the spring member, positioned between the two longitudinally
floating members provides a longitudinal force which is applied directly to the
flexible longitudinal sealing element, leading to stretching and'or tearing of said
member.

A design, which offers a mechanical seal component which is fully, or partly
manufactured in an economical manner such as a pressing operation and which
includes a drive design which is not limited to the material thickness, is deemed to be
particularly advantageous.
Our GB2391275 application defines a method of improving the drive mechanism in
assemblies containing thin, pressed materials. However, because of the substantially
annular surface of each member contained in said drive mechanism and the assembly
of said members, the invention mechanism is limited to comprise of two separate and
substantially different drive member designs; one substantially U-shaped and one
substantially L-shaped. Said different drive member designs can lead to assembly
errors and/or lead to extended assembly time. Furthermore, the L-shape members are
not optimised to provide an improved drive surface area, over and above the thickness
of the substantially thin material of construction.
It is therefore deemed to be advantageous if the drive mechanism between two
members of a seal, incorporates a substantially thick surface drive area, and can be
assembled in such a manner that assembly errors are eliminated, assembly' time'cost is
reduced and subsequent retainment operations to longitudinally constrain said
members are eliminated.
Subsequent retainment operations are defined as punching or staking operations which
deform at least one component after the assembly of said components thereby prevent
at least two parts from disassembling.
It is deemed to be further advantageous if the two longitudinally separated members,
which are sealed with a common sealing member, are longitudinally restrained before
applying a stretching force on said sealing member.
A design where the raw material creation process thereafter has no subsequent
machining operations such as turning, milling or drilling is of further advantage.

Furthermore, it is advantageous if the seal assembly incorporates a minimum number
of components, and or the components are of simple construction, thereby helping
further to reduce the cost of the assembly.
Description of the drawings
The accompanying drawings are as follows:
Figure 1. shows a partial cross sectional view of the first embodiment of the
imention.
Figure 2, corresponds to Figure 1 and shows a partial isometric view with drive
surface area greater than the material thickness of the member.
Figure 3. corresponds to Figure 2 and shows an isometric view of the drive ring of the
invention.
Figure 4. shows an alternate partial isometric view of the imention.
Figure 5. by way of example only, shows a partial isometric view of an alternate drive
mechanism of the invention.
Figure 6. corresponds to Figure 5 and shows an exploded isometric view of the
invention.
Figure 7, shows a partial cross sectional view of a modular dual component seal of
the invention.
Figure 8. corresponds to Figure 7 and shows a partial isometric \iew of the modular
dual component seal of the imention.

Figure 9, shows by way of example only the dual component seal of the invention,
mounted in a gland forming a low cost dual cartridge seal.
Figure 10, shows a single cartridge seal of the invention.
Detailed description of the Invention
The invention will now be described, by way of examples only, with reference to the
accompanying drawings.
The general principle of mechanical seals in accordance with the present invention
may be used not only in the case where the shaft is a rotary member and the housing is
a stationary member but also the reverse situation, that is to say. in which the shaft is
stationary and the housing is rotary.
Furthermore, the invention may be embodied in both rotary and stationary
arrangements, cartridge and component seals with metallic components as well as
non-metallic components.
Referring to Figure 1 of the accompanying drawings, there is illustrated, of a
mechanical seal 10. shown in longitudinal section, of the invention mounted in an
item of rotating equipment (9).
The rotary and axially floating seal face (11) is spring biased towards a static
stationary seal face (12). The rotary seal face (11) is allowed to slide on the static seal
face (12). The interface between the rotan, seal face (11) and stationary seal face (12)
forms sealing area (13). This sealing area (13) is the primary seal that prevents the
process media (14) from escaping from the process chamber (15).

In addition to the sliding seal face (13), the process media (14) is sealed by a rotaiy
elastomeric member (16) in contact with the shaft (17) and rotary seal face (II). This
provides a first secondary sealing area.
The second secondary sealing area is formed between stationary' seal face (12) and
stationary gland plate assembly (21) using elastomeric member (22).
The third secondary sealing area is formed between the gland plate assembly (21) and
the process chamber (15) using gasket (26).
The three secondary sealing devices and the primary sliding sealing interface pre\ent
the process media (14) from escaping from the process chamber (15).
The static seal face (12) is prevented from rotating by radial squeeze between the
elastomeric member (22) and the gland plate assembly (21). It is deemed obvious that
an alternate anti-rotation device could be incorporated into the design if so desired.
The rotary sealing assembly (26) consists of rotary holder (27). Said rotary holder
(27). is preferably a pressed metallic construction and incorporates a radially
extending portion 20, which abuts to one end of a longitudinal spring (28). Said rotary
holder (27) transmits the longitudinal spring (2S) force to the rotary seal face (11).
Drive ring (29) is fitted to the radially outwardly portion of elastomeric member (16).
Said drive ring (29) radially compresses elastomeric member (16) to form a seal to the
shaft (17).
The rotational movement from the shaft (17) is transmitted through the elastomeric
member (16) to drive ring (29). Thereafter, drive ring (29) transmits said rotational
movement to the rotary holder (27) by at least one drive lug (30) engaging in one drive
slot (31).

The rotary holder (27) then transmits the rotational movement to the seal face (11) via
the radial compression of the elastomeric member (16).
It is deemed ob\ious that a variety of drive mechanisms could be incorporated into
said design to perform a drive between said rotary holder (27) and said seal face (11).
An example of such drive mechanism is a pin in a slot.
Said drive ring (29). is preferably a pressed metallic construction and incorporates a
radially extending portion 19. which abuts to the other longitudinal end of the spring
(28).
Figure 2. corresponds to Figure 1 and shows a partial isometric v iew of a further
design of the invention (40) where the drive surface area. (41) between the rotary
holder (42) and drive ring (43) is greater than the material thickness of the pressed
thin material of the drive ring (43).
From Figure 2. it will be noted that the drive ring (43) is axially captured in rotary
holder (42) by the enclosed slot (44) of drive ring (43).
Furthermore, the reader will note that at one longitudinal end of the rotary holder (42),
the material is radially displaced and includes a longitudinal return (45). This
maximises the drive area (41) in contact with the slot (partially remo\ed) in the rotary
holder (42).
Figure 3. corresponds to Figure 2 and shows an isometric view of the drive ring 43
illustrating radially protruding slot sides 50 and 51.
From Figure 2 arrd 3 the reader will clearly note that the drive surface area between
the rotary holder (42) and drive ring (43) is substantially greater than the thickness of
either material (52) given the axial return (45) feature and radially protruding slot
sides (50) and (51).

Figure 4, shows an alternate partial isometric view of a rotary seal (60) of the
invention, showing a different radially protruding drive area design, on this occasion
the radially protruding member (61) and longitudinal return (64) is shown on the
rotary holder (62) and interfaces with a radially larger drive ring (63).
Figure 5, corresponds to Figure 1 and. shows a partial isometric view of a rotary seal
(70) showing the preferred drive mechanism (71) of the invention.
From Figure 5, section A-A illustrates at least one radially extending drive lug (30) of
the rotary holder (27) engages in at least one slot 31 of the drive ring (29) thereby
transmits rotational drive between the two members.
Figure 6. corresponds to Figure 5 and shows an exploded isometric view of the
preferred embodiment of the invention.
From Figure 6 the respective inventive steps of the invention are clear to the reader.
Namely, how the radially extending drive lug (30) in the rotary holder (27) is
longitudinally restrained by wall (73) when inserted into the longitudinally closed slot
(31) of the drive ring (29). This is a preferred embodiment of the invention since this
longitudinal restraint prevents the forces from the spring being applied to the
elastomeric member 16. thereby stretching said member 16 in the un-installed
position.
A further embodiment of the invention is the assembly of the two parts 29 and 27. In
order to pass the radially protruding drive lug 30 of the rotary holder 27 past wall 73
of drive ring 29, at least one assembly slot 74 is provided in the drive ring 29. Said
assembly slot (74) serves no purpose other than to allow said drive lug (30) into initial
axial position before being rotationally moved, during assembly so that the drive lugs
ride over the outer radial surface (75) or drive ring (29) and engage in at least one of
the corresponding slots (31).

Preferably, a further embodiment of the invention is the two slits (76) and (77) at
either circumferential side of the drive lug (30). Said slits (76) provide a substantially
radialy flexible finger (78) adjacent to the drive lug (30). Said finger (78) aids the
assembly of the radially extending drive lug (30) into the enclosed slot (31).
Figure 7. shows a partial cross sectional view of a modular dual rotary component
seal (80) of the invention. Upon close review of Figure 7 in conjunction with Figure 1.
the reader will note that the rotary holder (27) and drive ring (29) are identical for both
single and dual component seal variants. Furthermore, the seal face (11) is also
common for both the inboard and outboard sealing positions, with a new elastomeric
member (81) the only additional new member to convert a single seal into a dual seal.
The modularity of the invention between said single and dual seal configurations is
yet a further preferred embodiment of the invention given it means that the tooling and
capital investment required to create such rotary holder (27) and drive ring (29)
members is shared between the two seal configurations.
Figure 8. corresponds to Figure 7 and shows a partial isometric view of the modular
dual component seal (80) of the invention.
Figure 9, shows by way of example only, the dual component seal (80) of the
invention, mounted in a gland (81) forming a low cost, longitudinally short, dual
cartridge seal.
Seal face lubrication may thereby be added through gland orifices 82 and 83 as the
experienced reader will understand. Said configuration and operation will not be
described furthermore.
Figure 10 shows a single cartridge seal of the invention in which the rotary
components are mounted on a sleeve 91. The elastomeric bellows 93 is shaped to seal
face 95 and rotary holder 97 at one end thereof and between sleeve 91 and drive ring

99 at its other end. By replacing the bellows 93 by another, appropriately shaped
bellows, the seal components can be used with a dual mechanical seal.
It is considered self evident to the experienced reader that the invention may be
employed for both Rotary seals and Stationary seals, single, double or triple
mechanical seals, whether designed in a cartridge or component seal format.
It is also considered self evident that the invention may be used with metallic
components as well as non-metallic components such as plastic. Some types of
equipment rotate the housing and have a stationary shaft. It is considered that the
invention can be similarly applied to such designs.
It is clear that the invention has many advantages in an increasingly more competitive
industrial environment, where value for money / low cost and high technical
performance solutions are required.

WE CLAIM
1. A seal comprising an elastomeric member, a spring biasing means, a longitudinally
floating first member, a longitudinally non-floating second member and a
longitudinally floating seal face, said elastomeric member being in sealing
engagement with said seal face and said first and second members and said spring
biasing means being longitudinally positioned between said seal face and said second
member, said first member and said second member being longitudinally restrained
and rotationally coupled by at least one substantially male radially protruding portion
in one of said members engaging in at least one substantially female portion in the
other of said members and said first and second members being arranged for sealing
engagement with said seal face in a single seal utilising a first elastomeric member, or
with said seal face and a further seal face in a double seal utilising a second
elastomeric member.
2. A seal according to any of the preceding claims, wherein said first and or second
member has a radially compliant portion substantially adjacent to said radially
protruding male and or female portions.

3. A seal according to am of the preceding claims, wherein rotational drive is
transmitted from said first member to said second member over a cross sectional
engagement area which is larger than the respective material thickness of either the
first and second member.
4. A seal according to any of the preceding claims, wherein at least one member
contains at least one radially extending portion, said radially extending portion
including a longitudinal return, said return corresponding to the radial and
longitudinal position of at least one slot in the corresponding member.
5. A seal according to any of the preceding claims, wherein said seal comprises a
rotating member and a stationary member, said members being slidable relative to one

another to form a seal, said stationary member being held in place by a gland plate,
said seal arrangement being a single component mechanical seal.
6. A seal according to Claim 5. wherein one of said members is a rotary member
which is connected to and radially displaced from a sleeve member, said sleeve
member extending in a longitundinal direction and terminating adjacent to a clamp
ring for connection to an item of rotating equipment, said seal being a single cartridge
mechanical seal.

A mechanical seal has a seal face 11 located is a rotary holder 27 which is spring biased away from a drive ring 19. An elastomeric bellows seals these components. The holder and drive ring are longitudinally restrained and rotationally coupled by at least one male portion 30 in one of these members engaging with a female portion in the other of these members.
The holder and the drive ring may be utilised in either a single seal or a double seal be
selecting an appropriately shaped elastomeric bellows.