GB2621827A - Scroll pump seal, scroll pump and method - Google Patents

Scroll pump seal, scroll pump and method Download PDF

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Publication number
GB2621827A
GB2621827A GB2212172.7A GB202212172A GB2621827A GB 2621827 A GB2621827 A GB 2621827A GB 202212172 A GB202212172 A GB 202212172A GB 2621827 A GB2621827 A GB 2621827A
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GB
United Kingdom
Prior art keywords
scroll
seal
scroll pump
annular protrusion
pump seal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
GB2212172.7A
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GB202212172D0 (en
Inventor
Zahradka Martin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Edwards sro
Original Assignee
Edwards sro
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Edwards sro filed Critical Edwards sro
Priority to GB2212172.7A priority Critical patent/GB2621827A/en
Publication of GB202212172D0 publication Critical patent/GB202212172D0/en
Priority to PCT/EP2023/072885 priority patent/WO2024042012A1/en
Publication of GB2621827A publication Critical patent/GB2621827A/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/0003—Sealing arrangements in rotary-piston machines or pumps
    • F04C15/0023—Axial sealings for working fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
    • F04C18/0207—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents both members having co-operating elements in spiral form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C19/00—Sealing arrangements in rotary-piston machines or engines
    • F01C19/005—Structure and composition of sealing elements such as sealing strips, sealing rings and the like; Coating of these elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C27/00—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids
    • F04C27/005—Axial sealings for working fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C27/00—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids
    • F04C27/008—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids for other than working fluid, i.e. the sealing arrangements are not between working chambers of the machine
    • F04C27/009—Shaft sealings specially adapted for pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
    • F04C18/0207—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents both members having co-operating elements in spiral form
    • F04C18/0246—Details concerning the involute wraps or their base, e.g. geometry
    • F04C18/0253—Details concerning the base

Abstract

Disclosed is a scroll pump seal 100 used to inhibit fluid flow into and out of a pumping chamber defined between a first scroll 12 and a second scroll 14 of a scroll pump, the first and second scroll are configured for relative orbital motion, the scroll pump seal comprising an annular body 18 adapted to be mounted about a shaft 16 of the scroll pump and fixed relative to one of the first scroll and the second scroll, and a first sealing element comprising an inner annular protrusion and an outer annular protrusion extending from an axial end surface of the annular body, the inner annular protrusion and the outer annular protrusion being configured to contact the other one of the first scroll and the second scroll that the annular body is not fixed relative to. The seal therefore could be u-shaped, n-shaped, v-shaped or ^-shaped

Description

SCROLL PUMP SEAL, SCROLL PUMP AND METHOD
FIELD OF THE INVENTION
The field of the invention relates to a scroll pump and, in particular, to a scroll pump seal for inhibiting fluid flow into and out of a pumping chamber defined between a first scroll and a second scroll of the scroll pump.
BACKGROUND
Scroll pumps comprising a first scroll and a second scroll configured for relative orbital motion are known. A pumping chamber is defined between the first scroll and the second scroll. A seal may be positioned between the first and the second scroll to inhibit leakage of fluid from outside the scroll mechanism into the pumping chamber. Whilst such scroll pumps exist, they can have drawbacks. Accordingly, it is desired to provide an improved scroll pump and scroll pump seal.
SUMMARY
One aspect provides a scroll pump seal for inhibiting fluid flow into and out of a pumping chamber defined between a first scroll and a second scroll of a scroll pump, the first and second scroll being configured for relative orbital motion, the scroll pump seal comprising: an annular body adapted to be mounted about a shaft of the scroll pump and fixed relative to one of the first scroll and the second scroll; and a first sealing element comprising an inner annular protrusion and an outer annular protrusion extending from an axial end surface of the annular body, the inner annular protrusion and the outer annular protrusion being configured to contact the other one of the first scroll and the second scroll that the annular body is not fixed relative to.
Some scroll pump seals prevent leakage into a pumping chamber (or flow path) of a scroll pump (or scroll mechanism) by providing a protrusion (or lip). For example, GB2503723B discloses a scroll pump having an axial lip seal located between an orbiting scroll and a fixed scroll for resisting leakage of fluid from -2 -outside the scroll mechanism into the flow path. The axial lip seal is fixed relative to the orbiting scroll or the fixed scroll and seals against the other of the orbiting scroll or the fixed scroll such that an orbiting motion is imparted to the seal relative to the other scroll. The axial lip seal comprises a lip angled towards a shaft of the scroll pump about which the axial lip seal is mounted.
The aspect recognises that there are shortcomings in the capability of such scroll pump seals to inhibit fluid leakage. In particular, these scroll pump seals fail to effectively prevent leakage of pumped media out of the pumping chamber.
io Moreover, the strength of the seal preventing leakage of unwanted fluid into the pumping chamber may be limited. Leakage of pumped material out of the pumping chamber can lead to a degradation of pumping performance of a scroll pump. Leakage of ambient fluid into a pumping chamber can also reduce pumping performance as well as potentially damaging the scroll pump. Leakage of a fluid into a pumping chamber can draw unwanted lubricant, oil and particulates into the pumping chamber which might be detrimental or damaging to the scroll pump.
Accordingly, the aspect provides a scroll pump seal. The scroll pump seal may inhibit fluid flow into and out of a pumping chamber defined between a first scroll and a second scroll of a scroll pump. The first and second scroll being configured for relative orbital motion. The scroll pump may be a scroll vacuum pump. The scroll pump seal comprises an annular body (or ring-shaped portion). The annular body may be adapted to be mounted about a shaft of the scroll pump.
The annular body may be fixed relative to one of the first scroll and the second scroll. The scroll pump seal may comprise a first sealing element. The first sealing element may be for sealing between the first and the second scroll of a scroll pump. The first sealing element may comprise an inner annular protrusion (or inner lip). The first sealing element may comprise an outer annular protrusion (or outer lip). The inner and the outer annular protrusions may extend from an axial end surface (or end portion) of the annular body. The inner annular protrusion and the outer annular protrusion may be configured to contact (or seal -3 -against) the other one of the first scroll and the second scroll that the annular body is not fixed relative to.
In this way, a scroll pump seal having two sealing protrusions is provided. The two protrusions can improve the seal strength against fluid movement in one or both directions. Hence, leakage into and out of the pumping chamber can be reduced. The one aspect also provides advantages over existing shaft seals. In particular, the high rotational speeds of pump shafts cause abrasion and thus shaft seals need to be replaced regularly. The speed of the relative orbital motion io between the first and the second scroll is less than the speed of rotation of the shaft. Accordingly, providing the first sealing element between the scrolls means that the scroll pump seal of the one aspect may last longer than a similar shaft seal would.
In some embodiments, the inner annular protrusion and the outer annular protrusion extend at an angle such that the inner annular protrusion is angled towards the shaft and the outer annular protrusion is angled towards the pumping chamber. In other words, the inner annular protrusion and the outer annular protrusion do not extend perpendicular to the axial end surface of the annular body. In this way, the inner annular protrusion is proficient at inhibiting leakage of ambient fluid, lubricant and particulates into the pumping chamber and the outer annular protrusion is particularly effective at inhibiting leakage of a pumped media out of the pumping chamber. Further, using angled protrusions can improve seal strength because the seal may strengthen as a differential pressure across the angled protrusions increases.
In some embodiments, the inner annular protrusion and the outer annular protrusion together define a V-shape. In this way, leakage both into and out of the pumping chamber can be mitigated because this shape forms particularly effective seals for fluid drawn towards and away from the pumping chamber. In some embodiments, the inner annular protrusion and the outer annular protrusion -4 -comprise a curved portion such that they are not entirely linear. This may help strengthen the seal as the differential pressure across the seal increases.
In some embodiments, the inner annular protrusion and the outer annular protrusion extend by the same length. In this way, the seal into and the seal out of the pumping chamber may be of similar strength.
In some embodiments, the outer annular protrusion extends beyond a radially outer surface the annular body. Longer protrusions may form a stronger seal as io they are pressed more into one of the first or second scrolls. However, there is a trade-off between saving space and seal strength when choosing the length of the protrusions.
In some embodiments, the scroll pump seal comprises a second sealing element for inhibiting fluid flow between the annular body and the shaft of the scroll pump, the second sealing element comprising a further annular protrusion (or lip) extending from a radially inner surface of the annular body. In this way, an additional seal blocking a flow path into and out of the pumping chamber is provided to further inhibit leakage into and out of the pumping chamber.
Accordingly, the strength of the seal and therefore pumping performance can be improved.
In some embodiments, the further annular protrusion is angled towards the axial end surface comprising the first sealing element. In this way, the further annular protrusion may be particularly proficient at preventing leakage into or out of the pumping chamber depending on which of the first and second scroll the scroll pump seal is fixed relative to.
In some embodiments, the second sealing element comprises a second further annular protrusion. In this way, the seal created by the second sealing element can be strengthened. Accordingly, leakage into and out of the pumping chamber can be further mitigated. -5 -
In some embodiments, the further and the second further annular protrusions together define a V-shape. In this way, one of the first further annular protrusion and the second further annular protrusion is particularly proficient at preventing leakage out of the pumping chamber and the other is particularly proficient at preventing leakage into the pumping chamber. This may reduce the total leakage.
In some embodiments, the scroll pump seal comprises a biasing member io configured to bias the first sealing element towards the other one of the orbiting scroll and the fixed scroll that the annular body is not fixed relative to. In this way, the sealing contact can be strengthened, thereby reducing leakage.
In some embodiments, the biasing member comprises a spring.
In some embodiments, the biasing member is integral to the annular body. In this way, the biasing member can be manufactured or formed with the scroll pump seal. In some embodiments, the biasing member is made of a same material as the annular body.
In some embodiments, the first sealing element comprises an intermediate annular protrusion (or lip) extending from the axial end surface of the annular body between the inner annular protrusion and the outer annular protrusion. In this way, an additional seal can be provided to improve the seal formed by the scroll pump seal. This embodiment can be particularly effective in combination with a biasing member to help all three protrusions (or sealing members or lips) to have sufficient contact with the other one of the first scroll and the second scroll that the annular body is not fixed relative to.
In some embodiments, the annular body and the first sealing element are integral with each other. In some embodiments, the annular body and the first sealing element are made of a same material. In some embodiments, the body and the -6 -second sealing element are integral with each other. In some embodiments, the annular body and the second sealing element are made of a same material.
In some embodiments, the annular body is fixed to the one of the first scroll and the second scroll via friction fit.
In some embodiments, the annular body comprises an annular groove containing an 0-ring for fixing the annular body to the one of the first scroll and the second scroll and for inhibiting fluid flow between the annular body and the one of the first scroll and the second scroll. In this way, the scroll pump seal can be fixed to the appropriate scroll and fluid flow between the scroll pump seal and the scroll is inhibited or prevented.
In some embodiments, the scroll pump seal is made of at least one polymer, optionally wherein the at least one polymer is Teflon filled polyamide.
In some embodiments, the scroll pump seal comprises grease positioned between the inner annular protrusion and the outer annular protrusion. In this way, the first sealing element can be supported and the seal strengthened.
Consequently, leakage can be reduced and pump performance increased. Similarly, when the scroll pump seal comprises a second sealing element comprising a further annular protrusion and a second further annular protrusion, grease may be disposed between these protrusions to increase seal strength.
A further aspect provides a scroll pump comprising: a first scroll and a second scroll configured for relative orbital motion; a shaft configured when driven to impart the relative orbital motion of said first scroll and said second scroll; a scroll pump seal according to one aspect, said scroll pump seal being mounted about said shaft and fixed relative to one of said first scroll and said second scroll.
In some embodiments, the scroll pump seal is made of a same material as tip seals of the first and second scrolls. -7 -
A yet further aspect provides a method of positioning a scroll pump seal comprising: mounting a scroll pump seal according to the one aspect about a shaft; and fixing said scroll pump seal relative to one of a first scroll and a second scroll such that said first sealing element contacts the other one of said first scroll and said second scroll that said annular seal is not fixed relative to, said first and second scroll being configured for relative orbital motion.
In some embodiments, the method includes positioning an 0-ring inside the io annular groove defined in the annular body of the scroll pump seal. This may be performed prior to fixing the scroll pump seal relative to one of the first and the second scrolls. However, the steps of the yet further aspect may be performed in any order.
Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.
Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which: Figure 1 shows a portion of a front sectional view through a scroll pump according to one embodiment; Figure 2 shows a portion of a front sectional view through a scroll pump 30 according to one embodiment; Figure 3 shows a portion of a front sectional view through a scroll pump according to one embodiment; and -8 -Figure 4 shows a flow diagram illustrating steps in a method of a method of positioning a scroll pump seal according to an embodiment.
DESCRIPTION OF THE EMBODIMENTS
Before discussing the embodiments in any more detail, first an overview will be provided.
Some embodiments provide a scroll pump seal for inhibiting fluid flow into and out of a pumping chamber (leakage). The pumping chamber is defined between a first scroll and a second scroll of a scroll pump. The first and second scroll are configured for relative orbital motion. The scroll pump seal comprises: an annular body adapted to be mounted about a shaft of the scroll pump and fixed relative to one of the first scroll and the second scroll; and a first sealing element comprising an inner annular protrusion and an outer annular protrusion extending from an axial end surface of the annular body, the inner annular protrusion and the outer annular protrusion being configured to contact the other one of the first scroll and the second scroll that the annular body is not fixed relative to.
Small flow paths exist between the components of a scroll pump. A seal can be positioned radially within an inner most wrap of a pumping chamber or scroll mechanism to help prevent leakage into and out of the inner most wrap. Existing seals are fixed relative to one of an orbiting scroll and a fixed stator scroll and have a single lip forming a seal against the scroll which it is not fixed relative to. The single lip is angled towards the shaft to help inhibit leakage into the pumping chamber. However, existing seals do not seal against leakage of a pumped media from inside the pumping chamber to outside the pumping chamber. Moreover, having only a single sealing lip means that known seals have limited strength.
By providing two sealing protrusions, the effective seal strength may be increased. Consequently, leakage in one or both directions into and out of the pumping chamber can be reduced. -9 -
The inner annular protrusion may be angled towards the shaft and the outer annular protrusion may be angled towards the pumping chamber. The protrusions may form a V-shape. By angling the sealing protrusions in opposing directions, an effective seal can be created inhibiting fluid flow into the pumping chamber and out of the pumping chamber.
Using an additional sealing element for sealing between the seal body and a shaft of the scroll pump can be used to further restrict fluid flow and leakage. This 10 second sealing element may have one or two protrusions. If two, they may be angled such that they form a V-shape.
A third protrusion can be added to either the first or second sealing elements to further enhance the seal. The third protrusion may be added between the already angled or V-shaped protrusions.
A biasing member can be provided to encourage the sealing protrusions of the first sealing element to create an effective seal. The biasing member may be a distinct feature or it may be integral with the body of the seal. If integral, the force 20 of the biasing member may be created by the shape and/or structure of the seal.
Another way to increase seal strength is by including grease between protrusions to resist collapse.
Scroll Pump As in known scroll pumps, a motor drives a shaft. The shaft effects relative orbiting motion to a set of scrolls. The relative orbiting motion pumps fluid along a flow path from an inlet to and outlet via a pumping chamber made up of multiple pockets. The flow path extends between the scrolls in a generally involute path.
More specifically, walls of the scrolls define wraps through which the fluid is moved and compressed towards the centre of the scrolls. As a result, there is a pressure difference across adjacent wraps. The wraps are sealed using tip seals -10 -as known in the art. However, further sealing may be required to prevent leakage into and out of the inner most wrap.
The relative high pressure of the inside wraps during pump operation means that the compressed gas wants to escape. The lowest resistance path is out of the pump outlet; however, fluid can escape from the scroll mechanism around the shaft and a front shaft bearing. Hence, leakage of a fluid out of the pumping chamber can occur.
The opposite problem arises when the pump is stopped and there is an immediate drop in pressure inside the scroll mechanism. Whilst the pumping chamber equalises, fluid from outside the pumping chamber under a higher ambient pressure may be sucked into the scroll mechanism and may drag other contaminants such as oil from the pump bearings. Hence, leakage of a fluid into the pumping chamber can occur.
Scroll Pump Seal Figure 1 shows an embodiment of a scroll pump seal 10 for use in a scroll pump to inhibit fluid flow into and out of a pumping chamber 30 defined between a first scroll 12 and a second scroll 14 of the scroll pump. The first scroll 12 and the second scroll 14 are configured for relative orbital motion. One of the first scroll 12 and the second scroll 14 may be a fixed or stator scroll and the other an orbiting scroll. Alternatively, they may both be orbiting scrolls. The relative orbiting motion is imparted to the scrolls by a motor driven shaft 16.
The scroll pump seal 10 comprises: an annular body 18 defining an annular groove 28 for receiving an 0-ring 26 and a first sealing element 20 having an inner annular protrusion 22 and an outer annular protrusion 24.
The seal 10 is positioned in an opening defined between the first scroll 12, the second scroll 14, and the shaft 16 at a location radially inward of the pumping chamber 30 (shown in Figure 2). The annular body 18 is mounted about the shaft 16 and is fixed relative to the first scroll 12.
The body 18 is fixed using a friction fit. More specifically, the seal 10 comprises an 0-ring 26 positioned within the annular groove 28 defined by the body 18. The 0-ring 26 is configured to fix the seal 10 relative to the first scroll 12 and inhibit fluid flow between the seal 10 and the first scroll 12.
The first sealing element 20 is integral with the annular body 18 and made from the same material as the body 18. The first sealing element 20 comprises an inner annular protrusion 22 and an outer annular protrusion 24. The protrusions 22, 24 extend away from the annular body 18 at opposing angles such that they form a V-shape with the inner annular protrusion 22 radially within the outer annular protrusion 24. An end of the protrusions 22, 24 contacts the second scroll 14 such that a seal is formed between the first scroll 12 and the second scroll 14.
The seal is formed both whilst the scrolls 12, 14 are stationary and moving (relative orbital motion).
In use, the seal 10 acts to inhibit fluid flow between the first scroll 12 and the second scroll 14, thereby inhibiting fluid flow or leakage into and out of the pumping chamber 30. The first sealing element 20 is configured to contact the second scroll 14 before, during and after operation of the scroll pump such that leakage is inhibited during the different operating conditions of the scroll pump. The inner annular protrusion 22 is particularly proficient at inhibiting leakage into the pumping chamber 30 being angled away from the pumping chamber 30. This is particularly useful immediately after the pump has stopped because this is when leakage into the pumping chamber 30 is prevalent as discussed above. The outer annular protrusion 24 is particularly proficient at inhibiting leakage out of the pumping chamber 30 being angled towards the pumping chamber 30. This is particularly useful whilst the pump is active because this is when leakage out of the pumping chamber 30 is prevalent as discussed above.
-12 -Modifications to the described embodiment will be apparent to those skilled in the art. For example, the annular body 18 may be fixed relative to the second scroll 14 rather than the first scroll 12. In this case, the first sealing element 20 contacts the scroll which the annular body 18 is not fixed relative to. Further, whilst the seal 10 is fixed relative to the first scroll by friction fit, any suitable attachment mechanism can be used, for example, by adhesive. The protrusions 22, 24 of the first sealing element 20 may not be angled -i.e., they may extend perpendicular to the axial end surface of the annular body 18. The protrusions 22, 24 may form a combination of straight and angled. The protrusions may extend at similar angles or different angles such that they are not symmetrical. These arrangements can provide an improved seal to reduce leakage into and out of the pumping chamber 30.
Figure 2 shows a second embodiment of a scroll pump seal. The scroll pump seal 100 is similar to seal 10 but with the addition of a second sealing element 36. The second sealing element 36 comprises at least one protrusion extending from a radially inner surface of the annular body 18. The second sealing element 36 is integral with the annular body 18 and made from the same material as the body 18. The protrusion is angled towards the axially end surface of the body 18 such that the protrusion is particularly proficient at inhibiting fluid flow out of the pumping chamber 30, through a shaft bearing, and into the ambient surroundings.
In use, the scroll pump seal 100 is similar to seal 10 with the exception that the second sealing element 36 provides a seal between the annular body 18 and the shaft 16 to inhibit leakage between these components before, during and after operation of the scroll pump -i.e., when the shaft 16 is rotated by a motor to effect relative orbital motion between the scrolls 12, 14.
Modifications to the described embodiment will be apparent to those skilled in the art. For example, the at least one protrusion of the second sealing element 36 may be angled towards or away from the pumping chamber 30 to inhibit leakage -13 -out of or into the pumping chamber 30. The at least one protrusion of the second sealing element 36 may comprise two protrusions. The at least one protrusion of the second sealing element 36 may not be angled -i.e., it may be perpendicular to the radially inner surface of the body 18. If there are two, the protrusions may form a V-shape. Alternatively, they may be angled differently. The protrusions of the first sealing element 20 and the second sealing element 36 may not be the same. The second sealing element 36 may comprise an intermediate protrusion similar to the one discussed below. These arrangements can provide an improved seal to reduce leakage into and out of the pumping chamber 30.
Figure 3 shows a third embodiment of a scroll pump seal. The scroll pump seal 1000 is similar to seal 10 but with the addition of a biasing mechanism 40 and the first sealing element 20 comprising an intermediate protrusion 38.
The intermediate protrusion 38 extends perpendicular to the axial end surface of the annular body 18 between the inner annular protrusion 22 and the outer annular protrusion 24. Similarly to the inner and outer annular protrusions 22, 24, the intermediate protrusion 38 is integral to and made of the same material as the annular body 18. The intermediate protrusion 38 provides an additional seal to further inhibit fluid flow between the first and the second scroll 12, 14, thereby reducing leakage.
The biasing mechanism 40 comprises a spring located on the axial end of annular body 18 opposite to that which the first sealing element 20 is located. In this way, the biasing mechanism 40 is configured to push against the first scroll 12 such that the inner and outer annular protrusions 22, 24 and the intermediate protrusion 36 are encouraged towards the second scroll 14 to enhance the strength of the seal.
In use, scroll pump seal 1000 is similar to seal 10 with the exception that the biasing member 40 encourages the inner and outer annular protrusions 22, 24 and the intermediate protrusion 38 towards the second scroll 14 to help maintain -14 -a seal, particularly during relative orbital motion between the first and second scroll 12, 14.
Modifications to the described embodiment will be apparent to those skilled in the art. For example, the intermediate protrusion 38 may be angled. Further, the biasing member 40 may be any suitable mechanism, not necessarily a spring. The biasing mechanism 40 may be integral with the annular body such that the structure of the annular body 18 naturally provides the biasing force. These arrangements can provide an improved seal to reduce leakage into and out of the io pumping chamber 30.
Figure 4 shows a flowchart of a method of positioning a scroll pump seal, for example, one of scroll pump seals 10, 100, 1000. At step 1010, the scroll pump seal is mounted about a shaft of a scroll pump, for example, shaft 16. At step 1020, the scroll pump seal is fixed relative to one of a first scroll and a second scroll of the scroll pump, for example, scroll 12 and scroll 14, such that a first sealing element of the scroll pump seal contacts the other one of the first scroll and the second scroll that the annular seal is not fixed relative to. The first and the second scroll are configured for relative orbital motion.
In other words, embodiments provide a seal (scroll pump seal) for sealing orbiting or rotating movement. One seal in some embodiments with 4 lips (2 pairs) that can protect against internal and external leaks. One pair is touching the orbiting scroll and second pair is touching the shaft. It is fitted into a drilling (opening) in the fixed scroll and sealed by the piston 0-ring in the groove by the 0-ring. It can seal to surface perpendicular to shaft and on the shaft as well. Provides effective sealing even with light pressure differences to 1bar. Using counter facing lips allows for faster bed-in and better sealing function.
This sealing solution improves GB2503723B and adds sealing against unwanted loss of the pumped media from pump. It can be expanded and provide additional sealing even on the shaft.
-15 -The seal is made from the same material as the tip seal which may be EKL HS11041 (PA, PTFE filled) or any polymer material with good sealing properties and sufficient wear resistance. The idea is that there is always slight overpressure (1,2bar(a)) in the centre of a fixed scroll and that gas wants to escape by way of the lowest resistance which is in majority by the exhaust. However, gas can escape from the mechanism around the front shaft bearing to the motor stator. Opposite issues arise when the pump is stopped and inside the mechanism pressure lower than surrounding atmosphere equalize. Embodiments seek to impede rapid ambient air rushing to the pumping mechanism. The solution for both of these problems can be found in form of multiple counter facing lips (protrusions) on the face of the seal facing perpendicular to the shaft and another set of counter facing lips (protrusions) abutting the shaft. The sealing surface quality is important for leak tightness and roughness for life of the seal.
To improve sealing effect in some embodiments grease can be applied between the lip pairs. Compared to conventional seals, this provides additional gas retention and provides an opportunity to seal on the shaft surface where higher surface quality can be achieved. In effect any lip provides some hurdle for the gas so configurations with multiple lips can improve sealing.
Embodiments provide a sealing solution with a crown shape sealing element actuated by a spring and additionally sealed around by an 0-ring. Leak tightness values of at least 10E-3 mbarlis can be achieved. The spring can be integrated to the seal by careful design for required stiffness and flexibility Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.
-16 -
REFERENCE SIGNS
10, 100, 1000 Seal 12, 14 Scroll 16 Shaft 18 Body First sealing element 22, 24 Protrusions 26 0-ring 28 Groove 30 Pumping chamber 32 Tip seals 34 Wraps 36 Second sealing element 38 Intermediate protrusion 40 Biasing member

Claims (16)

  1. -17 -CLAIMS1. A scroll pump seal for inhibiting fluid flow into and out of a pumping chamber defined between a first scroll and a second scroll of a scroll pump, said first and second scroll being configured for relative orbital motion, said scroll pump seal comprising: an annular body adapted to be mounted about a shaft of said scroll pump and fixed relative to one of said first scroll and said second scroll; and a first sealing element comprising an inner annular protrusion and an outer annular protrusion extending from an axial end surface of said annular body, said io inner annular protrusion and said outer annular protrusion being configured to contact the other one of said first scroll and said second scroll that said annular body is not fixed relative to.
  2. 2. The scroll pump seal of claim 1, wherein said inner annular protrusion and said outer annular protrusion extend at an angle such that said inner annular protrusion is angled towards said shaft and said outer annular protrusion is angled towards said pumping chamber.
  3. 3. The scroll pump seal of any preceding claim, wherein said inner annular protrusion and said outer annular protrusion together define a V-shape.
  4. 4. The scroll pump seal of any preceding claim, wherein said scroll pump seal comprises a second sealing element for inhibiting fluid flow between said annular body and said shaft of said scroll pump, said second sealing element comprising a further annular protrusion extending from a radially inner surface of said annular body.
  5. 5. The scroll pump seal of claim 4, wherein said further annular protrusion is angled towards said axial end surface comprising said first sealing element.
  6. 6. The scroll pump seal of claim 4 or 5, wherein said second sealing element comprises a second further annular protrusion.
  7. -18 - 7. The scroll pump seal of claim 6, wherein said further and said second further annular protrusions together define a V-shape.
  8. 8. The scroll pump seal of any preceding claim, wherein said scroll pump seal comprises a biasing member configured to bias said first sealing element towards said other one of said orbiting scroll and said fixed scroll.
  9. 9. The scroll pump seal of claim 8, wherein said biasing member comprises a 10 spring.
  10. 10. The scroll pump seal of claim 8 or 9, wherein said biasing member is integral to said annular body.
  11. 11. The scroll pump seal of any preceding claim, wherein said first sealing element comprises an intermediate annular protrusion extending from said axial end surface of said annular body between said inner annular protrusion and said outer annular protrusion.
  12. 12. The scroll pump seal of any preceding claim, wherein said annular body comprises an annular groove containing an 0-ring for fixing said annular body to said one of said first scroll and said second scroll and for inhibiting fluid flow between said annular body and said one of said first scroll and said second scroll.
  13. 13. The scroll pump seal of any preceding claim, wherein said scroll pump seal is made of at least one polymer, optionally wherein said at least one polymer is Teflon filled polyamide.
  14. 14. A scroll pump comprising: a first scroll and a second scroll configured for relative orbital motion; -19 -a shaft configured when driven to impart the relative orbital motion of said first scroll and said second scroll; a scroll pump seal according to any preceding claim, said scroll pump seal being mounted about said shaft and fixed relative to one of said first scroll and said second scroll.
  15. 15. The scroll pump of claim 14, wherein said scroll pump seal is made of a same material as tip seals of said first and second scrolls.io
  16. 16. A method of positioning a scroll pump seal comprising: mounting a scroll pump seal according to any one of claims 1 to 13 about a shaft; and fixing said scroll pump seal relative to one of a first scroll and a second scroll such that said first sealing element contacts the other one of said first scroll and said second scroll that said annular seal is not fixed relative to, said first and second scroll being configured for relative orbital motion.
GB2212172.7A 2022-08-22 2022-08-22 Scroll pump seal, scroll pump and method Pending GB2621827A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB2212172.7A GB2621827A (en) 2022-08-22 2022-08-22 Scroll pump seal, scroll pump and method
PCT/EP2023/072885 WO2024042012A1 (en) 2022-08-22 2023-08-21 Scroll pump seal, scroll pump and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2212172.7A GB2621827A (en) 2022-08-22 2022-08-22 Scroll pump seal, scroll pump and method

Publications (2)

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GB202212172D0 GB202212172D0 (en) 2022-10-05
GB2621827A true GB2621827A (en) 2024-02-28

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GB2212172.7A Pending GB2621827A (en) 2022-08-22 2022-08-22 Scroll pump seal, scroll pump and method

Country Status (2)

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GB (1) GB2621827A (en)
WO (1) WO2024042012A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001227480A (en) * 2000-02-14 2001-08-24 Mitsubishi Heavy Ind Ltd Scroll type fluid machinery
US20050123428A1 (en) * 2001-06-29 2005-06-09 Kazuhide Uchida Scroll compressor
EP1698784A1 (en) * 2005-03-04 2006-09-06 Copeland Corporation Scroll machine with single plate floating seal
CN208203565U (en) * 2018-05-03 2018-12-07 宁波汇峰聚威科技股份有限公司 A kind of sealing structure of screw compressor

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000073969A (en) * 1998-08-27 2000-03-07 Tokico Ltd Scroll type fluid machine
DE102008054753A1 (en) * 2008-12-16 2010-06-17 Robert Bosch Gmbh Internal gear pump
GB2503723B (en) * 2012-07-06 2015-07-22 Edwards Ltd Scroll pump with axial seal
CN108278204B (en) * 2018-02-07 2023-12-19 宁波汇峰聚威科技股份有限公司 Sealing device of vortex compressor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001227480A (en) * 2000-02-14 2001-08-24 Mitsubishi Heavy Ind Ltd Scroll type fluid machinery
US20050123428A1 (en) * 2001-06-29 2005-06-09 Kazuhide Uchida Scroll compressor
EP1698784A1 (en) * 2005-03-04 2006-09-06 Copeland Corporation Scroll machine with single plate floating seal
CN208203565U (en) * 2018-05-03 2018-12-07 宁波汇峰聚威科技股份有限公司 A kind of sealing structure of screw compressor

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WO2024042012A1 (en) 2024-02-29
GB202212172D0 (en) 2022-10-05

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