GB2533120A

GB2533120A - Transmission unit

Info

Publication number: GB2533120A
Application number: GB1421939.8A
Authority: GB
Inventors: David Thomas Barry; Michael Scott Jonathan; Leslie Thomas Stephen
Original assignee: HALIFAX FAN Ltd
Current assignee: HALIFAX FAN Ltd
Priority date: 2014-12-10
Filing date: 2014-12-10
Publication date: 2016-06-15
Also published as: GB201421939D0

Abstract

A transmission unit 102 for a rotatable body 108, such as a fan casing 100, the transmission unit comprising a hub 122 provided with a passage having a support shoulder defining an internal diameter of the hub; a rotatable mounting boss 120 having an elongate member that extends through the hub passage, the elongate member is provided with a support shoulder which defines an external diameter of the boss elongate member; the hub support shoulder diameter is greater than the boss support shoulder diameter such that the boss support shoulder can be located within the hub support shoulder; the hub and mounting boss having complementary geometries such that they are moveable between a first relative position in which the boss support shoulder is supported by the hub support shoulder; and a second relative position in which boss support shoulder is spaced apart from the hub support shoulder such that they are rotatable relative to one another.

Description

TRANSMISSION UNIT

The present disclosure relates to a transmission unit.

In particular the disclosure is concerned with a transmission unit for a rotatable body.

Background

Pumping fluid through a duct is a common requirement in many industrial processes. The fluid may be a gas, liquid or combination of the two. For example the supply of fluid may be required to provide cooling, as part of a chemical reaction, or to carry a particulate from one region of a processing system to another.

Fan units comprising an impellor may be employed to pump the fluid. A fan unit 10 known in the art is shown in Figure 1. The fan unit 10 comprises an impellor 12 mounted within an impellor housing 14. The impellor 12 is mounted to a shaft 16 which extends through a bearing unit 18, through a wall of the housing 14 and is coupled to the impellor 12.

Figure 2 shows an exploded view of parts of the fan unit 10 of the related art. It shows that the shaft 16 extends to couple with a mounting boss 20 which is bolted to the impellor 12. Thus the impellor 12 is carried by the shaft 16.

In some processing plants it is necessary to seal the housing 14 and the duct to which it is connected from the external environment. For example, if the duct is delivering food stuffs it is important to maintain a seal such that contaminants cannot enter the duct. Alternatively, if the duct is transmitting harmful material, it is desirable that a seal is provided such that the material does not leak to the external environment.

Sealing arrangements which achieve this are well known in the art, for example the seal housing 22 with seal member 24 shown in Figure 1 and Figure 2. Hence with the shaft 16 in place, a seal is provided between the seal housing 22 and the shaft 16 such that fluid may not pass between the housing 14 and the external environment.

However, seal members 24 of the sealing unit 22 only have a finite life and need to be maintained and/or replaced, as do components of the bearing unit 18. In order to gain access to these assemblies, the sealing unit 22, bearing unit 18 and shaft 16 must first be removed. With the shaft removed, there is a fluid passage conduit between the inside of the housing 14 and the external environment via the passage left open by the absence of the shaft 16.

Additionally, since the impellor 12 is mounted to the shaft, the housing 14 must be opened so that the impellor 12 can be in some way supported while the shaft 1615 removed.

Opening up and exposing the fan casing internals requires careful consideration and risk assessment due to the potential for leakage of contaminants into or out of the ductwork.

Hence a transmission unit configuration which enables inspection, maintenance and/or replacement of transmission unit components plus a means for supporting the impellor without having to dismantle or breach the impellor housing, is highly desirable.

Additionally, a transmission unit configuration which enables inspection, maintenance and/or replacement of transmission unit whilst still providing a seal between an impellor housing and the environment which surrounds it, is also highly desirable.

Summary

According to the present disclosure there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

Accordingly there may be provided a transmission unit for a rotatable body, the transmission unit comprising: a hub provided with a through passage having a support shoulder defining an internal diameter of the hub; a rotatable mounting boss having an elongate member configured to extend through the hub passage, the elongate member provided with a support shoulder which defines an external diameter of the boss elongate member; the hub support shoulder diameter being greater than the boss support shoulder diameter such that the boss support shoulder may be located within the region of the hub support shoulder; the hub and mounting boss having complementary geometries such that they are moveable between: a first relative position in which the boss support shoulder is supported by the hub support shoulder; and a second relative position in which boss support shoulder is spaced apart from the hub support shoulder such that the hub and mounting boss are rotatable relative to one another.

The hub support shoulder diameter may be greater than the boss support shoulder diameter.

A first seal member may be provided between the hub and the boss configured and located to provide a fluid seal when the hub and boss are in the first relative position but not the second relative position.

The mounting boss may comprise a mounting member which extends from the elongate member, the mounting member being configured for engaging with a rotatable component.

The hub may comprise a locking arrangement for locking the mounting boss relative to the hub.

The locking arrangement may comprise a threaded passage in the hub, and a complementary threaded pin which may be extended to retain the mounting boss to thereby hold the boss relative to the hub.

The transmission unit may further comprise a transmission shaft which extends through and is driveably engageable with the mounting boss.

The transmission unit may further comprise: a seal housing configured to engage with an end of the hub opposite to the mounting boss end of the hub; and bounds the shaft.

The seal housing may comprise: a second seal member for sealing between the seal housing and the boss elongate member when the boss is assembled in the hub; and a third seal member for sealing between the seal housing and the shaft.

The transmission unit further may further comprise a bearing unit configured to couple to the seal arrangement and bound the shaft; and is provided with bearing means for rotatably supporting the shaft.

The transmission unit may further comprise a locking stud which extends through a passage provided along the shaft such that the locking stud extends beyond the mounting boss to engage with a first locking nut and extend beyond the other end of the shaft to engage with a second locking nut such that when assembled the stud shaft and two locking nuts clamp the mounting boss and shaft together to thereby prevent relative movement of the boss and shaft.

There may be provided a fan unit comprising: a housing having a wall and a transmission unit according to the present disclosure wherein the hub extends through an aperture in the wall and is mounted to the wall such that the mounting member of the mounting boss is inside the housing; and the hub extends from inside the housing to outside of the housing.

The wall aperture may be defined by a support ring resiliently mounted to the housing wall, the hub being mounted to the support ring.

The support ring may be mounted on a resilient member; and the resilient member may be mounted on the housing, the support ring thereby being moveable relative to the housing.

Hence there is provided a transmission unit and fan unit which are configured such that, when the shaft is removed, they provide a means to support an impellor of the fan unit, and to provide a seal, if required, between the inside of the fan unit housing and the environment outside of the fan unit housing.

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 shows a fan unit of the related art, as previously discussed; Figure 2 shows a transmission unit of the fan unit as shown in Figure 1; Figure 3 shows a side view of a fan unit and transmission unit according to the present disclosure; Figure 4 shows a side sectional view of the fan unit and transmission unit as shown in Figure 3; Figure 5 shows a perspective view of the outside of a fan unit and transmission unit of the

present disclosure and as shown in Figures 3, 4;

Figure 6 shows a sectional view of an example of a transmission unit according to the present disclosure; Figure 7 shows the same view as presented in Figure 6, with the components in a different configuration; and Figure 8 shows an exploded view of the transmission unit as shown in Figures 6,7.

Detailed Description

A transmission unit, fan unit, method of assembly and disassembly of a transmission unit and fan unit according to the present disclosure will now be described with reference to Figures 3 to 8.

Figures 3 to 8 show views of a fan unit assembly 100 comprising a transmission unit 102 of the present disclosure. The fan unit comprises a housing 104 having a wall 106 which encloses an impellor 108. The housing 104 defines a chamber 110 within which the impellor 108 is rotatable and which fluid to be pumped by the impellor 108 enters via an inlet 112, and exits via an exhaust duct 114.

The transmission unit 102 comprises a mounting boss 120 which is coupled to the impellor 108. The transmission unit 102 further comprises a hub 122 which extends through an aperture 124 in the wall 106. The hub 122 is mounted to the wall 106 such that a mounting member 126 of the mounting boss is inside the housing 104 and the hub 122 extends from inside the housing 104 to outside of the housing 104 to provide an interface with the other transmission unit components.

The transmission unit 102 is mounted to a support platform, or "stool" 130, such that it is reliably supported at the correct height relative to the impellor 108 and the housing 104.

Details of the transmission unit will now be described in more detail with reference to Figures 6, 7 and 8.

The transmission unit 102, configured for rotating a rotatable body such as an impellor 108, comprises the hub 122, which is stationary relative to the housing 104. The hub 122 is provided with a through passage 140 having a support shoulder 142 which defines an internal diameter of the hub 122. The mounting boss 120, which is rotatable relative to the housing 104, has an elongate member 144 configured to extend through the hub passage 142. The elongate member 144 is provided with a support shoulder 146 which defines an external diameter of the boss elongate member 144.

The support shoulder 146 may be provided as a ring or rib structure which extends away from the elongate member 144. The boss support shoulder 146 may be provided as a continuous ring around the elongate member 144 and the mounting boss 120. Alternatively the boss support shoulder 56 may comprises a series of raised features on the elongate member 144 of the mounting boss 120.

The hub support shoulder 142 has a diameter greater than the boss support shoulder 142, their relative values being such that the boss support shoulder 146 may be located within the region defined by the hub support shoulder 142.

That is to say, the diameter of the hub support shoulder 146 and the diameter of the boss support shoulder 142 are chosen such that the boss support shoulder 142 can enter, and rest upon, the ring defined by the hub support shoulder 146.

The hub 122 and mounting boss 120 have complementary geometries such that they are axially moveable between a first relative position, in which the boss support shoulder 146 is supported by the hub support shoulder 142, as shown in Figure 7, and a second relative position in which the boss support shoulder 146 is spaced apart from the hub support shoulder 142, as shown in Figure 6.

A first seal member 150 is provided between the hub 122 and the boss 120. The first seal member 150 may be provided as a static seal. The first seal member 150 is configured and located to provide a fluid seal when the hub 122 and boss 120 are in the first relative position, as shown in Figure 7, but to not provide a fluid seal the second relative position, as shown in Figure 6.

In the first relative position configuration shown in Figure 7, the boss 120 is located slightly to the right of where it is shown in Figure 6, such that it makes a fluid seal contact with the first seal member 150, and the shoulder 146 is moved into contact with shoulder 142.

Thus in the first relative position, shown in Figure 7, the boss 120 is carried and supported by the hub 122. In the second relative position, shown in Figure 6, the features of the boss 120 and hub 122 are spaced apart such that the hub 122 and mounting boss 120 are rotatable relative to one another without coming into contact with one another. That is to say, in the second relative position all of the features of the hub 122 and mounting boss 120 are spaced apart from one another such that in normal operation, the hub 122 and mounting boss 120 are relatively rotatable relative to one another.

The hub support shoulder 142 has an internal diameter which is greater than the outer diameter of the boss support shoulder 146.

That is to say, there may be a nominal clearance between some regions of the the hub support shoulder 142 and the boss support shoulder 146.

In the configuration shown in Figure 6 the first seal member 150 extends from a sealing land on the hub 122 radially inwards towards the elongate member 144 of the mounting boss 120. In normal operation, i.e. in the second relative position as shown in Figure 6 when the boss 120 is rotatable relative to the hub 122, the seal member 150 does not provide a fluid seal, and is not in substantive contact with the elongate member 144 of the boss 120. However, a shoulder 152 which extends from the elongate member 144 provides a sealing surface 154 against which the first seal member 150 will make a seal when the boss 120 is drawn into the first relative position, as shown in Figure 7, with the hub 122 i.e. during the process of disassembly.

The mounting boss 120 further comprises a mounting member 160 which extends from the elongate member 144 and the shoulder 152. The mounting member 160 is configured for engagement with a rotatable component, that is to say the impellor 108.

The hub 122 comprises a locking arrangement 162 for locking the mounting boss 120 relative to the hub 122. The locking arrangement 162 comprises a threaded passage 164 in the wall of the hub 122, and a complementary threaded pin 166 which may be extended to clamp against the elongate member 144 of the mounting boss 120 and thereby clamp, hold and/or retain the boss 120 relative to the hub 122, as shown in Figure 7.

A drive/transmission shaft 170 extends through, and is driveably engageable with, the mounting boss 120. The shaft 170 is rotatable relative to the hub 122. The shaft 170 has an end which enters a passage 172 in the mounting boss 120. Hence one end of the shaft 170 engages with the mounting boss 120. In the example shown the shaft 170 extends through the wall 106 into a region of the mounting boss 120 which sits in the cavity 110 of the housing fan unit, and extends away from the mounting boss 120 to the outside of the casing 104 of the fan unit 100.

A seal housing 174 is fitted to an end of the hub 122 which extends outside of the casing 104, opposite to the mounting boss end of the hub 122. That is to say the seal housing 174 is coupled to the end of the hub 122 which sits proud of the housing 104 in the environment which surrounds the fan unit 100. The seal housing 174 bounds the shaft 170.

The seal housing 174 comprises a second seal member 176 for sealing between the seal housing 174 and the elongate member 144 of the boss 120 when the seal unit 174 is assembled in the hub 122. There is also provided a third seal member 178 for sealing between the seal housing 174 and the shaft 170.

The bearing unit 102 is configured to couple to the seal arrangement 174 and bound the shaft 170. The bearing unit 102 is provided with bearing means 180,182 for rotatably supporting the shaft 170. The bearing means 180,182 may comprise roller bearings, ball bearings or any other appropriate form of bearing which permits the shaft 170 to rotate relative to the bearing unit 102.

In the example shown, the shaft 170 has a stepped profile which in combination with a pair of bearings 180, 182 acts to prevent axial movement of the shaft 170 relative to the other parts of the transmission unit 102. An end cap 184 is provided at the end of the bearing unit distal to the sealing unit 174 to trap one of the bearing arrangements 183 against the stepped profile of the shaft 170.

A locking stud 186 extends through a passage 188 provided along the length of the shaft 170. The passage 188 may be provided by a drilling operation down the centre of the shaft 170. Hence, when assembled, the locking stud 186 extends out of the passage 188 and beyond the mounting boss 120 to engage with a first locking nut 190 which spans the mounting boss passage 172. The locking stud 186 also extends out of the opposite end of the passage 188 at the opposite end of the shaft 170 to engage with a second locking nut 192. When the shaft 170, locking nuts 190, 192 and mounting boss 120 are assembled, the stud shaft 186 and locking nuts 190, 192 clamp the mounting boss 120 and shaft 170 together to thereby prevent relative movement of the mounting boss 120 and the shaft 170.

The wall aperture 124 is defined by a support ring 200 resiliently mounted to the housing wall 106. The hub 122 is mounted to the support ring 200. The support ring 200 is mounted on a resilient member 202, and the resilient member 202 is mounted on the wall 106 of the housing 104 by a clamp ring 203. Hence the support ring 200 is movable relative to the housing 104 by virtue of the resilient member 202. That is to say the support ring 200 may provide a flexible and or moveable mounting.

Although not shown in the drawings, a motor drive may be attached to the end of the shaft 170 distal to the housing 104, that is to say, at the same end of the shaft 170 as the second locking nut 192.

The first seal member 150, second seal member 176 and third seal member 178 may comprise a lip seal, carbon ring, gland seal or labyrinth seal or some combination of such. Other configurations of sealing members may also be utilised as appropriate. The sealing members may be stationary or rotate with the shaft and mounting boss 120.

The fan unit 100 and transmission unit 102 of the present disclosure may be dismantled in the following manner First the drive motor/arrangement attached to the second locking nut 192 end of the shaft 170 is removed. Bolts attaching the bearing housing 102 to the stool 130 are then removed. The bearing unit 172 is then disengaged from the seal arrangement 174, leaving the seal arrangement attached to the hub 122. The bearing unit 102 is then pulled away from the fan casing 104 until the impellor mounting boss 120 is drawn into the mounting hub 122, as shown in Figure 7.

With the seal arrangement 174 fixed to the hub 122, the seals 176,178 retain a fluid seal between the inside of the fan unit and the external environment. As the bearing unit 102 is pulled away from the fan casing 104 the hub 122 and mounting boss 120 are moved from the assembled second relative position configuration, in which the boss support shoulder 146 is spaced apart from the hub support shoulder 142 such that the hub 122 and mounting boss 120 are rotatable relative to one another, to achieve the first relative position, as defined above, in which the boss support shoulder 146 is supported by the hub support shoulder 142.

Having moved the hub and mounting boss into the first relative position, the first seal member 150 provides a fluid seal between the hub 122 and the boss 120, thereby providing a fluid seal between the inside of the fan unit and the external environment. Being sandwiched between the boss 120 and the hub 122, the first seal member 150 may also support the boss 120. The locking pin 166 is then screwed fully down such that the pin 166 is clamped against the elongate member 144.

After this stage, if required, the seal arrangement 174 can be removed, as a fluid seal is provided by the first seal member 150. This provides a user with convenient access to the second seal member 176 and third seal member 178 whilst retaining a sealed fan unit.

In this configuration, the impellor 144 and mounting boss 120 are firmly held (i.e. retained) in the hub 122. The second retaining nut 192 at the end of the shaft 170 is then removed. The bearing unit 102 may then be fully withdrawn by undoing the locking stud 186.

The locking nut 190 provides a fluid barrier that prevents leakage from the chamber 110 via the passage 172 of the mounting boss 120. Thus the shaft 170, sealing arrangement 174 and bearing unit 102 can accessed for inspection, maintenance and/or replacement whilst the mounting boss 120 is seated within the hub 122 with the impellor 108 attached to the mounting boss 120 without risk of passage of contaminants to/from the chamber 110.

Reassembly of the fan unit and transmission unit is the reverse of the above process.

Thus there is provided a transmission unit and fan unit which is easily dismantled and reassembled, which may provide a gas tight seal even in a dismantled state. The configuration and location of the first seal member 150 is such that it does not suffer wear during rotation of the impellor 108. Hence the life of the first seal member is extremely long, and the first seal member 150 may only need to be replaced extremely rarely, and perhaps not at all, during the life of the fan unit 100. Consequently the housing 104 need not be dismantled to access the first seal member 150.

Thus there is provided a configuration which may be easily, and quickly maintained whilst retaining and isolating internals of the fan casing, thereby reducing maintenance downtime.

Although the device of the present disclosure is discussed with reference to the sealing member 150, providing a gas tight design, and an impellor mounting arrangement (i.e. shoulders 142,146), the latter may be employed independently of the former. That is to say, the impellor mounting arrangement may be employed in configurations where it is not required to seal between the fan unit and the surrounding environment. Thus there is provided a transmission unit that can be maintained without need for disturbing the associated fan casing and/or the impellor and system ductwork. It may be incorporated in configurations where fan units must remain sealed during maintenance (i.e. "gas tight") and configurations where a seal between the fan unit and the external environment need not be maintained during maintenance.

The transmission unit is of a modular design, and hence just the bearing unit may be removed for maintenance leaving the seal arrangement in place, or the bearing unit and seal arrangement may both be removed, whilst supporting the impellor and/or retaining a gas tight assembly.

The resilient member 202, provided as a flexible membrane, provides greater build tolerances, and hence is an aid to centring the shaft during assembly. It also provides vibration damping.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1 A transmission unit for a rotatable body, the transmission unit comprising: a hub provided with a through passage having a support shoulder defining an internal diameter of the hub; a rotatable mounting boss having: an elongate member configured to extend through the hub passage, the elongate member provided with a support shoulder which defines an external diameter of the boss elongate member; the hub support shoulder diameter being greater than the boss support shoulder diameter such that the boss support shoulder may be located within the region of the hub support shoulder; the hub and mounting boss having complementary geometries such that they are moveable between: a first relative position in which the boss support shoulder is supported by the hub support shoulder; and a second relative position in which boss support shoulder is spaced apart from the hub support shoulder such that the hub and mounting boss are rotatable relative to one another.
2 A transmission unit as claimed in claim 1 wherein the hub support shoulder diameter is greater than the boss support shoulder diameter.
3 A transmission unit as claimed in claim 1 or claim 2 wherein a first seal member is provided between the hub and the boss configured and located to provide a fluid seal when the hub and boss are in the first relative position but not the second relative position.
4 A transmission unit as claimed in claim 3 wherein the mounting boss comprises a mounting member which extends from the elongate member the mounting member configured for engaging with a rotatable component.
A transmission unit as claimed in any one of claims 1 to 4 wherein the hub comprises a locking arrangement for locking the mounting boss relative to the hub.
6 A transmission unit as claimed in claim 5 wherein the locking arrangement comprises a threaded passage in the hub, and a complementary threaded pin which may be extended to retain the mounting boss to thereby hold the boss relative to the hub.
7 A transmission unit as claimed in any one of the preceding claims further comprising a transmission shaft which extends through and is driveably engageable with the mounting boss.
8 A transmission unit as claimed in any one of claims 1 to 7 wherein the transmission unit further comprises: a seal housing configured to engage with an end of the hub opposite to the mounting boss end of the hub and bound the shaft.
9 A transmission unit as claimed in claim 8 wherein the seal housing comprises: a second seal member for sealing between the seal housing and the boss elongate member when the boss is assembled in the hub; and a third seal member for sealing between the seal housing and the shaft.
A transmission unit as claimed in any one of claims 8, 9 wherein the transmission unit further comprises a bearing unit configured to couple to the seal arrangement; and bound the shaft; the bearing unit being provided with bearing means for rotatably supporting the shaft.
11 A transmission unit as claimed in any one of claims 8 to 10 further comprising a locking stud which extends through a passage provided along the shaft such that the locking stud extends beyond the mounting boss to engage with a first locking nut and extend beyond the other end of the shaft to engage with a second locking nut such that when assembled the stud shaft and two locking nuts clamp the mounting boss and shaft together to thereby prevent relative movement of the boss and shaft.
12 A fan unit comprising: a housing having a wall and a transmission unit according to any one of claims 1 to 11 wherein the hub extends through an aperture in the wall and is mounted to the wall such that the mounting member of the mounting boss is inside the housing; and the hub extends from inside the housing to outside of the housing.
13 A fan unit as claimed in claim 12 wherein the wall aperture is defined by a support ring resiliently mounted to the housing wall, the hub being mounted to the support ring.
14 A fan unit as claimed in claim 13 wherein the support ring is mounted on a resilient member; and the resilient member is mounted on the housing, the support ring thereby being moveable relative to the housing.
A transmission unit substantially as hereinbefore described and/or as shown in Figures 3 to 7.
16 A fan unit substantially as hereinbefore described and/or as shown in Figures 3 to 7.
17 A method of assembly of a transmission unit substantially as hereinbefore described and/or as shown in Figures 3 to 7