GB2158536A - Rotary connection for supplying a heat transfer medium to a roller - Google Patents

Abstract

A rotary connection for use in supplying a heat transfer medium to ducting in a rotating roller comprises a stationary connection 2 to which a supply 20 and a discharge line 30 lead.The connection 2 is mounted on a spigot 1 which is fixed for rotation with the roller by means of two axially spaced ball races 3, 4. A rotating mechanical seal 5 is provided between the spigot and the connection. <IMAGE>

Description

SPECIFICATION Improvements In or Relating to a Rotary Connection for Supplying a Heat Transfer Medium to a Roller The present invention relates to a rotary connection for supplying a heat transfer medium to a roller.

When rollers are utilised to apply pressure ducting a production process, for example, it is often necessary to provide a heat transfer medium, such as hot water, steam, oil, or a saline solution which is pumped through ducting present in the roller in order to heat or cool the working surface of the roller to a desired temperature which is different from the ambient temperature or, in certain circumstances, in order to maintain the working surface of the roller at an ambient temperature if the roller surface temperature would otherwise vary from the ambient temperature.

The ducting present in the roller may be in the form of a plurality of bores extending substantially parallel to the axis of the roller, or one or more conduits extending with a spiral configuration through the body of the roller. Alternatively the roller may be constituted by a relatively thin-wall outer cylinder which is spaced from the core of the roller, thus providing a cylindrical duct adjacent the wall of the outer cylinder.

The roller, with its internal ducting, rotates in use while the lines which supply and discharge of the heat transfer medium remain stationary. To form a connection between the stationary supply and discharge lines and the rotating roller it is necessary to provide a rotary connection which, conventionally, is mounted on one of the trunnions by which the roller is supported.

In one proposed rotary connection of this type a spigot is provided which is secured to the end face of the trunnion. The spigot is effectively two coaxial conduits. A stationary connection is provided which surrounds the spigot and carbon bearings are provided between the spigot and the connection.

The necessary sealing is constituted by partspherical axial seals provided with ring gaskets or glands.

It has been found, with this known construction, that it is difficult to maintain an adequate seal over protracted periods of use of the roller, particularly when the roller is operated at different operating temperatures. Also, problems arise at starting up and on shutting down the apparatus. Mountings using carbon bearings and part-spherical axial gaskets are not very accurately manufactured and after some time tend to wear. This may give rise to leakage.

The present invention seeks to provide an improved rotary connection.

According to this invention there is provided a rotary connection for supplying and discharging a heat transfer medium to a roller, said connection comprising a spigot adapted to be axially connected to a trunnion of the roller and a stationary connection cooperating with the spigot, the connection being provided with means for connection to supply and discharge lines so that a heat transfer medium may be supplied through the supply line, pass through the connection, pass through ducting present in the roller and return through the connection to the discharge line, the said connection being mounted on the spigot by means of two axially spaced bearings, a rotating mechanical seal being provided between the spigot and the connection.

Preferably the spaced bearings each comprise a ball race.

The two axially spaced bearings, which can be considered to be radial bearings, provide means mounting the connection on the spigot which are independent of the state of wear of the seal. The rotary mechanical seal may be fabricated from materials suitable for use at the temperature range in which the roller will operate, even if this temperature is above 250 C.

Advantageously the mechanical seal comprises a first ring mounted on the spigot against which is biased a second ring by means sealingly connected to the stationary connection, the two rings having a low mutual coefficient of friction. Thus in a preferred embodiment one or both of the rings may consist of a material having good sliding properties. A seal of this kind may be very durable and offers a minimum of drag.

Of course, a seal of this kind requires inspection at predetermined intervals, and from time to time it will be necessary to replace one or other of said rings. Thus, in order to obtain access to the interior of the rotary connection, in a preferred embodiment of the invention the stationary connection is adapted to be withdrawn from the roller away from the spigot after retaining means have been released.

This is in direct contrast with the prior art construction in which, to obtain access to the interior of the rotary connections, it was necessary to remove the spigot from the end face of the trunnion. Thus, in the known construction, the spigot was secured to the trunnion by means of a conical clamp connection with split conical rings.

A preferred embodiment of the invention incorporates a positive connection between the spigot and the trunnion, which is superior to the conical clamp connection as regards simplicity.

In a preferred embodiment of the invention the second ring of the seal is sealed to the fixed part of the connection by a corrugated metal bellows, and is pressed against the first ring of the seal. Thus the mechanical seal and the application of the appropriate axial pressure forces are both provided by the corrugated metal bellows. Such a bellows may have the advantage of retaining its elastic properties over a relatively wide temperature range and, unlike a plastics bellows, such a metal bellows does not become brittle at low temperatures, nor does it suffer any damage at temperatures of more than 250 C, such as may occur when a roller is heated.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevational view, in part longitudinal section, of one embodiment of a rotary connection in accordance with the invention, and Figure 2 is a view corresponding to Figure 1 showing a second embodiment of the invention.

In the drawings like parts carry like reference numerals.

Referring initially to Figure 1 of the accompanying drawings a rotary connection, having the general reference 1, consists of a spigot 1,which is adapted to rotate with the roller, and a stationary connection 2.

The spigot 1 is a substantially tubular element and it is secured, by means of a flange 11 disposed at the right hand side of the spigot as shown in Figure 1, to the end face of the trunnion of a roller (the trunnion is not shown in Figure 1, but will be located to the right hand side of the flange 11 as illustrated).

Towards the free or left hand end of the tubular spigot one or more radial apertures 12 are formed in the cylindrical element that constitutes the spigot to permit the radial flow of heating medium from the interior of the spigot 1 to the exterior thereof, and vice versa.

The stationary connection 2 is in the form of a shortthick-walled cylinder surrounding the spigot.

Two spaced apart ball races 3, 4 are located between the spigot and the connection 2 in order to support the spigot whilst it rotates within the connection 2.

The ball race 3 is provided at the left hand end of the spigot 1, as illustrated and the ball race 4 is located substantially at the mid point of that part of the spigot which is contained within the connection 2.

A rotating mechanical seal having the general reference 5 is provided between the right hand end of the connection 2 and the rotating spigot 1 in order to prevent any leakage of the heat transfer medium.

The mechanical seal 5 consists of a first ring 6 of material having a low coefficient of friction which is clamped between the ball race 4 and a shoulder present on the exterior of the spigot 1. A second ring 7 is provided which cooperates with the ring 6 and which is urged into firm contact with the ring 6 by means of an annular metal corrugated bellows 8. In view of the nature of the material constituting the ring 6 and the ring 7, whilst a sealing effect is provided there is a very low coefficient of friction, and thus virtually no drag is created.

The bellows 8, at the end thereof remote from the ring 7, is connected to an extension 2" of the main part 2' of the connector 2 by being clamped thereto by means of an annular washer 9 which is retained in position by a plurality of bolts 23 which also serve to hold the axially adjacent parts 2', 2" of the connection 2 together.

When the heat transfer medium is to have a relatively high temperature, i.e. a temperature in excess of 250 C, the materials of the components constituting the mechanical seal 5 are selected appropriately, so as to be able to resist such temperatures without deteriorating.

The connection 2 is assembled by initially locating on the spigot the annular part 2" of the connection with the associated bellows 8 and seal 5. The ball race 4 is then located in position and annular retaining segments 10 are then positioned in a groove present on the exterior of the spigot. The retaining segments are tightened and are thus in contact with the inner surface of the ball race 4. The rest of the connection 10 is then located in position and the bolts 23 are tightened. The connection is then firmly fixed on the spigot 1. In order to remove the connection the above-described procedure is reversed, and thus the screws 23 are first released, thus permitting the part 2', and the associated elements to be removed from the spigot. After releasing the retaining segments 10 the rest of the connection 2 may be removed from the spigot.

In the embodiment of the invention illustrated in Figure 1 the flange cover 14 is connected to a bent pipe or conduit 15 to which a supply line 20, for example can be connected to supply heat transfer medium to the roller in the direction of the arrow.

After passing through the ducting present in the roller the heat transfer medium will flow through the space between the inner periphery of the spigot 1 and the outer periphery of the pipeline 13, and will then pass through the aperture or apertures 12 into a small annular chamber located between the connection 2 and the spigot 1 in the region between the ball races 3 and 4, and from thence the heat transfer medium will flow through a radially orientated outlet port 17 to a discharge line 30, as indicated by the arrow.

It is to be appreciated that the direction of flow of heat transfer medium through the described connection may be reversed if desired.

A pipe line 13 is provided which is coaxial with the spigot and extends through the interior of the spigot 1 at a distance from the inner wall surface of the spigot 1. In the embodiment illustrated in Figure 1 the pipeline 13 is secured to a flange cover 14 that constitutes a transverse end of the connection 2.

The pipeline 13 is thus stationary, even when the spigot rotates. The described arrangement will be found to be of particular use if the roller with which the described connection is utilised contains a stationary core which, together with a relatively thin cylindrical outer shell, defines a cylindrical conduit or cavity within the roller, the cavity being adapted to receive the flow of heat transfer medium.

Referring now to Figure 2 of the accompanying drawings the illustrated rotary connection 200 is basically very similarto the rotary connection 100 described above and those parts that carry the corresponding reference numerals will not be redescribed. However, in the rotary connection 200 the pipeline 13' is not stationary but, instead, rotates with the spigot 1. Thus the pipeline 13' is not directly connected to the flange cover 14'. Heat transfer medium supplied through the supply line 20 can thus flow into a chamber 18 located between the flange cover 14' and the pipeline 13' and consequently an additional seal 19 has to be provided between the ball race 3 and the end of the spigot to prevent a direct flow of heat transfer medium from the inlet 20 to the outlet 30 without passing through the ducting in the roller.

Claims (10)

1. A rotary connection for supplying and discharging a heat transfer medium to a roller, said connection comprising a spigot adapted to be axially connected to a trunnion of the roller and a stationary connection cooperating with the spigot, the connection being provided with means for connection to supply and discharge lines so that a heat transfer medium may be supplied through the supply line, pass through the connection, pass through ducting present in the roller and return through the connection to the discharge line, the said connection being mounted on the spigot by means of two axially spaced bearings, a rotating mechanical seal being provided between the spigot and the connection.

2. A connection according to claim 1 wherein the spaced bearings each comprise a ball race.

3. The two axially spaced bearings, are radial bearings, provide means mounting the connection on the spigot which are independent of the state of wear of the seal.

4. A connection according to any one of the preceding claims wherein the rotary mechanical seal is fabricated from materials suitable for use at a temperature above 250 C.

5. A connection according to any one of the preceding claims wherein the mechanical seal comprises a first ring mounted on the spigot against which is biased a second ring by means sealingly connected to the stationary connection, the two rings having a low mutual coefficient of friction.

6. A connection according to claim 5 wherein the second ring of the seal is sealed to the fixed part of the connection by a corrugated metal bellows, and is pressed against the first ring of the seal.

7. A connection according to any one of the preceding claims wherein the stationary connection is adopted to be withdrawn from the roller away from the spigot after retaining means have been released.

8. A rotary connection substantially as herein described with reference to and as shown in Figure 1 of the accompanying drawings.

9. A slurry connection substantially as herein described with reference to and as shown in Figure 2 of the accompanying drawings.

10. Any novel feature or combination of features disclosed herein.