EP0947628B1 - Roller - Google Patents

Description

The invention relates to a roller with a roller shell, with a heat exchanger inside the roll shell is arranged and with a supply arrangement for the inflow and outflow of an external heat transfer fluid is connected to its primary side and with a Circuit of an internal heat transfer fluid, which is the secondary side of the heat exchanger and the roll shell.

Such a roller is known from DD 225 767 A1.

Such rollers are used in calenders to make paper webs or to process other material webs. They work with other rollers to form one Nips together.

Another area of application is cooling or heating a material web, for example a paper web, also outside of a nip.

The need to cool the roller arises not only when the web of material, for example the paper web to be cooled. In some cases cooling is also necessary if the roller has elastic cover and heat by the Flexing of the elastic cover occurs during operation, must be dissipated to damage the surface to avoid.

In other applications, the roller is heated necessary, for example when a paper web is in a calender not only with increased pressure, but also also subjected to an elevated temperature shall be.

It is known here, the heat transfer fluid, for example a cooling water or heating steam, not only direct into the roller, but the effect to exercise via a heat exchanger. In the beginning DD 225 767 A1 will be the cycle for maintain the internal heat transfer fluid during cooling, that the heat transfer fluid in a gas and is in a liquid phase. It condenses on the heat exchanger and is then attached to the inner wall of the Rolled jacket hurled where it evaporates. The steam in turn gets to the heat exchanger.

Such a cycle only works for certain Differences in temperature and only for cooling. He can only be controlled to a very limited extent.

The object of the invention is to influence the temperature to design the roller differently.

This task is performed on a roller of the type mentioned Art solved in that the cycle one in the Has arranged roller pump arrangement.

One can therefore the circulation of the inner heat transfer fluid controlled with the help of the pump. You are no longer relied on that the heat transfer fluid in a certain form, for example under operating conditions can evaporate. One can heat transfer from the roll shell to the heat exchanger or in the opposite direction vary in larger areas because you have the circulation of the internal heat transfer fluid better control through the circulation. The inner Heat transfer fluid is forced to circulate. Despite this The only advantage outside the roller is a rotating union necessary for the external heat transfer fluid. Since the heat transfer fluid only flows through the heat exchanger, but not the roller shell, you can think of that Make heat transfer fluid less demanding. The The roller can also be used as a heating roller. This can the roller is also operated at lower temperatures be condensed in the steam because the steam only must be passed through the heat exchanger. One can a pump arrangement finally also with old rollers retrofit to adapt them to the new design.

The pump arrangement is preferably stationary in the Roller arranged and rotates with it. Accordingly are none in the circuit for the internal heat transfer fluid moving connections necessary. The risk that one such a connection is not leaky. The attachment of the pump is also simplified. Movable mounting of the pump is not necessary.

The pump arrangement is advantageously on one end face arranged the roller. It's easily accessible there, for example for maintenance purposes. Usually stands there is still enough space at the front of the roller Available.

It is preferred that the pump arrangement one Surrounding the roll neck in a ring. This has the advantage that thereby the weight distribution in the circumferential direction is not uneven by the pump arrangement. Accordingly, there is a risk of imbalance small.

In a preferred embodiment, the pump arrangement at least one pump that is radial at least is as far out as the radially outermost part of the cycle. This means that the pump has practically no suction power against centrifugal force. In the in most cases the heat transfer fluid of the pump will then fed by the centrifugal force. Definitely the heat transfer fluid is always in this configuration at the pump inlet.

The pump preferably has an externally operable one Work item on. Depending on the design of the pump the working element is a piston that moves back and forth or a rotating element, for example a Impeller that is rotated. Other Pump types are conceivable, for example gear pumps or centrifugal pumps. The work element must be in all Pumps are driven in some way. If now the drive takes place from the outside, i.e. from outside the roller, then the roller must drive the pump no additional energy can be supplied. This saves further connections.

It is particularly preferred that the working element when the roller rotates with a stationary drive arrangement interacts. Therefore one uses the Rotational movement of the roller to make a relative movement generate between the pump and the drive assembly. The work element can then be moved via this relative movement the pump are driven. For example you can with a rotary pump, in which the working element rotates, one with the working element in torque transmitting Connected drive wheel on a friction or tooth surface surrounding the pump arrangement let it roll. The drive wheel turns and the faster the higher the speed of the Roller is. This increases the pump performance at higher ones Speeds, which is often required because at higher speeds a correspondingly higher working speed is present, i.e. a greater length of the too treat material web per unit of time is. If the pump is a different one Pump is, for example a piston pump, then you can use the piston or an associated one Tappet, for example on a control curve run along. If the plunger or the piston with a Restoring force, for example a return spring is loaded, then it is sufficient if the control curve of acts in one direction on the plunger. The pestle can also be operated in that the pump arrangement when rotating the roller on a rotating one Drive wheel rests. Whenever the pestle under that Drive wheel, it is pressed inwards. The the same effect can be achieved, for example, if you have the pump arrangement with a revolving Belt that surrounds at least one position from the Pump arrangement is lifted off. Then the pestle can be pushed out of the pump again. For closer Details will be posted on the postpublished German patent applications 197 56 152 and 198 09 080 directed.

The external heat transfer fluid is advantageously supplied to the heat exchanger centrally and the drain radially further out. This has the advantage that the centrifugal force a certain pumping effect on the outside Heat transfer fluid is exerted. This makes it easier Control of the heat transfer fluid.

In a preferred embodiment, the secondary side of the heat exchanger several axially parallel tubes on, which are arranged in an exchange chamber, the communicates with the feed port. With a Such a heat exchanger arrangement can be relatively large exchange surface for heat transfer from the outside to the inner heat transfer fluid or vice versa. The arrangement has a heated roller above furthermore the advantage that steam acts as an external heat transfer fluid is used on the outside of the pipes can condense to heat on the through the pipes to release flowing internal heat transfer fluid. The condensate would in itself worsen the heat transfer. Because of the rotation of the roller, it will But condensate is immediately thrown off the pipes. The heat transfer surfaces are therefore "self-cleaning".

In another preferred embodiment, the Heat exchanger a through which the inner heat transfer fluid can flow Manifold on which is a flow path of the outer heat transfer fluid, the manifold has several openings, the circumferential and Are distributed axially. Such an arrangement is preferably used for chill rolls. That in that Manifold cooled heat transfer fluid through the Forced pipe promoted using the pump assembly is then partially under the pressure of the pump and partially under the action of centrifugal force outwards against the radial inside of the roll shell hurled or sprayed. There can then be heat take up.

Fig. 1

eine als Kühlwalze ausgebildete Walze im schematischen Querschnitt an einem Ende,

Fig. 2

eine Heizwalze im schematischen Querschnitt und

Fig. 3

einen Schnitt III-III nach Fig. 2.

The invention is described below with reference to preferred embodiments in conjunction with the drawing. Show here:

Fig. 1

a roller designed as a cooling roller in schematic cross section at one end,

Fig. 2

a heating roller in schematic cross section and

Fig. 3

a section III-III of FIG. 2nd

Fig. 1 shows the left in a schematic longitudinal section End of a cooling roller 1. The roller 1 has a roller shell 2, which carries an elastic cover 3. The Roller 1 acts with a counter roller 4 for the treatment of a Material web not shown together. The cover 3 is periodically tumbled and heated yourself. The heat generated must be dissipated.

For this purpose, a heat exchanger 5 is inside the Roll shell 2 arranged, so in a cavity 6, which is surrounded by the roll shell 2. The cavity 6 is terminated at both ends by end plates 7, which are screwed to the roller shell 2.

The cavity 6 is thus liquid-tight.

The heat exchanger 5 is with a supply arrangement 8 connected, which is a feed line 9 for a heat transfer medium, for example chilled water, and one Has discharge line 10 for the removal of this water. A pump 11 is shown schematically Controller 12 feeds the feed line 9, and a tank 13, in which the water is pumped back again. Not A cooling device is shown in more detail. With help of the controller 12 or the pump 11 can by Heat exchanger 5 determines the amount of cooling water flowing become.

The feed line 9 runs centrally here, i.e. in the Area of rotation of the roller 1. The discharge line 10 surrounds the feed line 9, so that at one Turning point 14, which is also at the other end of the roller 1 can be arranged due to a small promotional effect the centrifugal force.

The discharge line 10 is surrounded by a distribution pipe 15, which has openings 16 which are in the axial direction and are arranged distributed in the circumferential direction. The result The heat exchanger formed rotates with the roll shell Second

At the front end of the roller 1, i.e. on the axial Outside of the face plate 7 is a pump arrangement 17 screwed on. The pump arrangement 17 is above a Feed channel 18 with the cavity 6 in connection. The feed channel 18 is arranged so that it in the cavity 6 just inside the radial inner wall of the roll shell 2 opens. The feed channel 18 is in connection with the suction connection of the pump arrangement. The pressure connection of the pump arrangement 17 is via a Delivery channel 19 with the interior of the manifold in connection.

There is water or another cooling fluid in operation as an internal heat transfer fluid in the cavity 6. At the rotation of the roller 1, the water 20 through the Centrifugal force pressed against the roll shell 2 from the inside. There it is via the feed channel 18 with the help the pump assembly 17 is sucked off and through the delivery channel 19 promoted again in the distributor pipe 15. There it flows along the discharge line 10 and gives to the cooling water flowing therein, which is an external heat transfer fluid forms the heat. From the distributor pipe 15 it exits through the openings 16 and becomes partly under the effect of the pump pressure and partly under the action of centrifugal force against which Sprayed inside wall of the roll shell 2. If the openings 16 are small enough, atomization is effected or at least a spray of water, like this that the water the heat from the roll shell 2 even better can record.

The pump arrangement 17 has in the present exemplary embodiment several individual pumps on the circumferential direction are evenly distributed. Every single pump is designed as a rotary pump, for example as Vane pump. Each pump has a gear 21 as Drive element that meshes with a toothed ring 22, which is arranged stationary. So if the roller 1 rotates, then the gears 21 roll in the toothed ring and drive the working element via a shaft 23 the rotary pump, for example the impeller.

The pumps of the pump arrangement 17 are radially relative far out, i.e. at least as far as the radially outermost one Part of the circuit of the internal heat transfer fluid 20. Accordingly, the pump assembly 17 do not suck in against the centrifugal force, only promote against the centrifugal force because the heat transfer fluid 20 are pressed radially inwards again must to get to the heat exchanger.

The toothed ring 22 and the gear 21 form a drive arrangement, the pump assembly 17 in dependence from the speed of the roller 8 drives from the outside. The faster the roller 1 rotates, the larger is also the drive power and thus the conveying power the pump arrangement 17. This effect is wanted because at a higher working speed also results in a higher cooling requirement. Possibly you can also select the toothed ring 22 with a Speed in the same or opposite direction drive to the roller to other funding for the Adjust pump assembly 17. Instead of a gear ring you can also simply provide a friction surface on which a drive wheel rolls under friction.

2 and 3 show a heating roller in schematic Cross-section, with the corresponding parts with the same Reference numerals are provided.

The heat exchanger 5 has a variety of Tubes 24 on the inner heat transfer fluid (Waser), which is fed via the conveyor channel 19, is flowed through. This is done at the front ends Distribution rooms 25 for evenly distributing the Water provided on the tubes 24. In this case steam forms the external heat transfer fluid, which through the Feed line 9 is supplied and in an exchange chamber 27 arrives, in which the tubes 24 are arranged. The steam gives its heat to the internal heat transfer fluid in the tubes 24 and condenses. condensing Steam, i.e. water 20, collects below the effect of the centrifugal force outside, i.e. on the inside of the roll shell 2, the peripheral holes 26 is enforced. The holes 26 in turn are in turn via the feed channels 18 with the pump arrangement 17 in connection. The pump assembly 17 promotes the inner heat transfer medium via the delivery channels 19, for example also water, on the secondary side of the heat exchanger 5, namely inside of the tubes 24, which in turn are connected to the bores 26 are.

The primary side of the heat exchanger is through the cavity 27 formed in which the tubes 24 are arranged. If water now flows through the tubes 24, then condenses the steam on the outer surface of the pipes. This usually worsens heat transfer, is not critical in the present case, however, because the rotation of the roller 1 any water that at the Surface of the tubes 24 condensed, spun off becomes. So the heat exchanger surfaces are "Self-cleaning".

It can be seen that also in the design according to 2 and 3, the steam is supplied centrally, during the removal of the condensate (the external heat transfer fluid) further out. However, it is The discharge line 10 is only arranged as far outside that it still fits through the shaft journal 29. The condensate 28 does not have to be radial against the centrifugal force be promoted inwards again.

2 and 3, the pump arrangement 17 several pumps 30, which act as a piston pump are trained. Every piston pump has a plunger 31. A friction wheel 32 lies on the outer Surface 33 of the pump assembly 17. If so now Tappet comes under the friction wheel 22, then it becomes inward emotional. As soon as he has passed the friction wheel 32, it is represented by the power of one not shown Return spring pushed out again. Thus each pump 30 actuated once during one revolution. If you use several friction wheels 32, then you can also get a larger number of pump games per Carry out one revolution.

With a chill roll you can get an even heat distribution due to a high flow velocity in the Reach circulation of the internal heat transfer fluid. It there is no contamination of the roller by deposits of the Cooling water. The quality of the cooling water (external Heat transfer fluid) are no higher requirements posed more. Outside the roller there is only one rotating union and a control valve for the amount of cooling water necessary.

With the heating roller (Fig. 2 and 3) also result Advantages of using the pump arrangement 17. A Operation is also possible at lower temperatures because you can easily accept a condensate. The condensate of the external heat transfer fluid does not have to be transported radially inwards. On the inside Heat transfer fluid is a transport of condensate without Difficulties with the help of the pump arrangement possible. Accordingly, there is no transport of condensate Aid of slip steam is required, which is the scheme complicated and increased energy consumption. The Heat exchanger has a high efficiency because it is self-cleaning. Again, you can get a relative use a simple rotating introduction. The pump performance is also speed dependent.

In both cases, the pump arrangement can also be used retrofit existing rollers.

Claims (10)

1. Roller (1) with a roller casing (2), with a heat exchanger (5) which is arranged within the roller casing (2), and with a supply arrangement (8) for the supply and discharge of an external heat transfer fluid connected on the primary side of said heat exchanger, and with a circuit for an internal heat transfer fluid, said circuit containing the secondary side of the heat exchanger (5) and the roller casing (2), characterized in that the circuit has a pump arrangement (17) arranged in the roller (1).
2. Roller according to Claim 1, characterized in that the pump arrangement (17) is arranged at a fixed location in the roller (1) and rotates with the latter.
3. Roller according to Claim 1 or 2, characterized in that the pump arrangement (17) is arranged on one end face of the roller (1).
4. Roller according to Claim 3, characterized in that the pump arrangement (17) annularly surrounds a roller journal (29).
5. Roller according to one of Claims 1 to 4, characterized in that the pump arrangement (17) has at least one pump (30) which lies radially at least as far outwards as the radially outermost part of the circuit.
6. Roller according to Claim 5, characterized in that the pump (30) has a working element (31, 21) capable of being actuated from outside.
7. Roller according to Claim 6, characterized in that, during the rotation of the roller (1), the working element co-operates with a stationary drive arrangement (22, 32).
8. Roller according to one of Claims 1 to 7, characterized in that the supply of the external heat transfer fluid to the heat exchanger (5) takes place centrally and discharge takes place radially further outwards.
9. Roller according to Claim 8, characterized in that the secondary side of the heat exchanger (5) has a plurality of axially parallel tubes (24) arranged in an exchanger chamber (27) which is connected to the supply connection.
10. Roller according to Claim 8, characterized in that the heat exchanger (5) has a distributor tube (15) through which the internal heat transfer fluid is capable of flowing and which surrounds a flow path of the external heat transfer fluid, the distributor tube (15) having a plurality of orifices (16) which are distributed in the circumferential and the axial direction.

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