DE102013202237A1 - System for cooling electrical appliance in fiber web machine system, has cooling unit which conveys medium from medium line for cooling the electrical device, in which working medium is lubricating oil for use object - Google Patents

Abstract

The system (10) has an electrical device (12) and medium lines (16) for supplying medium to the use object (14) in the fiber web machine. A cooling unit (22) is provided for conveying the medium from the medium line on or in the electrical device for the purpose of cooling the electrical device with the medium. The working medium is lubricating oil for the use object in the fiber web machine. The cooling unit has connecting lines (28) for guiding lubrication oil from the medium line in or on electrical apparatus and back into the medium line.

Description

The subject of this invention is a system for cooling an electrical device in a fiber web machine, comprising an electrical device, medium lines for supplying medium to an insert object in the fiber web machine and cooling means for conveying the medium from the medium line to the electrical device for cooling of the same with the medium.

It is well known that electrical devices are all the more likely to break down or age, that is, weaken, the higher the temperature they are generally used. Electrical equipment can be manufactured to handle higher temperatures. Such electrical devices are, for example, intended for military use electrical equipment and electronics that tolerate temperatures up to about 85 ° C in continuous use. The military electrical equipment, however, requires more expensive investment than ordinary electrical equipment, for example for motor vehicles, to be used at operating temperatures below 65 ° C.

At several points of the fiber web machine, the process environment has a high temperature of up to more than 100 ° C. Such a process environment is found, for example, in the dryer section of the fiber web machine inside the hood. When the web breaks, the temperature rises, especially in the vicinity of the drying cylinder, since then eliminates the cooling of the cylinder material web. The cylinder cools slowly, even when the steam supply is shut off. In such a case, the temperature next to the drying cylinder, for example, rises from 100 ° C to 130 ° C. Another example is the proximity of the impingement flow dryer where excess heat can accumulate. The temperature of, for example, the electrical equipment within the dryer section hood then increases to high levels.

From the prior art ago is from the patent FI 118274 known to perform the cooling of the electrical device with compressed air. In this case, the electrical device to be cooled is an ultrasonic sensor which serves for determining the position of the fibrous web or the fabric in the transverse direction. However, an intensive use of compressed air for cooling increases the costs considerably, because the consumption of cooling energy adds up to a high value in the year, because in the dryer section of the fiber web machine more than 20 such places to be cooled can be present. In addition, the intensive use of the vortex tubes to be used for compressed air cooling requires an expert setting of the system.

The object of this invention is to provide a better system for cooling electrical equipment in a fibrous web machine, as compared to the prior art systems, with which energy consumption during cooling can be reduced. The characterizing features of this invention are evident from claim 1.

Surprisingly, the cooling of electrical equipment in the fiber web machine can be accomplished by means of the flow of a warm medium, because the circulation lubricating oil to be used in the bearing housings of the fiber web machine can be redirected by means of cooling means for cooling at least one electrical device. The warm oil flow is definitely cooler than its surroundings and its temperature can be regulated. In this way can be used for cooling the electrical device liquid medium, which has a much greater heat transfer capacity than gaseous medium. In addition, for cooling, the already existing largely circulation lubricating system can be used, so that the system can be realized without major changes to the fiber web machine.

Preferably, the cooling means are adapted to lead the leading to an insert object in the fiber web machine, belonging to the medium line flow line in its entirety for cooling to the electrical device and from there back to the mission medium leading medium. For example, the lubricating oil originally used to lubricate the bearings of rollers can be used to cool electrical equipment. If the entire flow is passed through the electrical device, the system can be realized without the need for a tapping or control valves and other control devices. At the same time the flow remains unthrottled, so that losses are avoided.

The cooling means preferably comprise connecting lines for conducting the circulating lubricating oil from the medium line to the electrical device and from there back into the medium line, as well as a housing for insulating the electrical device. With the housing, the electrical device can be shielded against the hot process environment, which reduces the need for cooling.

In general, as an application point of the invention in the fiber web machine, the interior of the hood of the dryer section, the vicinity of the Impallströmungstrockners, the hot calender or another corresponding point at which the ambient temperature is higher than the temperature of the circulating lubricating oil in question.

In the housing, a serving to eliminate moisture air flow can be brought into effect, which is derived through an opening in the housing from this. With the air flow moisture is removed from the interior of the housing and in this way the condensation of moisture on the surfaces of the housed in the housing cooled electrical device can be avoided or at least reduced.

Preferably, the cooling means comprise at least one heat exchange element, in whose connection the electronics to be cooled are arranged. Often, the contact of the components with the heat exchange element ensures sufficient cooling.

Further, the cooling means may comprise a Peltier element for transmitting heat from the electrical device to the recirculating lubricating oil arranged to turn on when the temperature of the electrical device is substantially equal to the temperature of the circulating lubricating oil. With the help of the Peltier element, the cooling can be continued to a temperature lower than the temperature of the circulating lubricating oil. Finally, the temperature of the electrical device may be considerably lower than the temperature of the circulating lubricating oil.

The Peltier element can have a power of 10-500 W, preferably 50-150 W. Even with low power consumption causes a significant reduction in the temperature of the electrical device below the temperature of the circulating lubricating oil.

The electrical device may consist of an optical measuring unit, an ultrasonic measuring unit or a mechanical position measuring unit. The measuring units in particular contain slightly aging electronics, such as LEDs, whose cooling brings cost savings in the form of a longer service life.

The circulation lubricating oil flow rate in the cooling means may be 0.1-10 l / min, preferably 1-3 l / min. Even with relatively small quantities of lubricants, electrical equipment can be sufficiently cooled.

The circulating lubricating oil may consist of lubricating oil as used for the lubrication of the bearings of the rolls belonging to the fiber web machine. Thus, an existing and already existing recirculating lubrication system can be used if the system is to be installed in existing machines.

More specifically, it is characteristic of the system according to the invention that circulating lubricating oil serves as the medium for an insert object in the fiber web machine.

With the system according to the invention, the cooling of electrical appliances is achieved at significantly lower operating costs than with systems according to the prior art. In addition, it is possible to intensify the cooling with a Peltier element, and the temperature of the element can be changed by controlling the current intensity of the Peltier element.

In the following, the invention will be described in detail with reference to the accompanying drawings, in which some embodiments of the invention are shown. Show it:

1 the system of the invention installed in the dryer section of a fiber web machine;

2 cooling an electrical device of the system according to the invention in a housing; the housing is shown in section;

3 a schematic drawing of the Peltier element.

1 shows an embodiment of the system according to the invention, in which with the system 10 an electrical device present in the dryer section of the fiber web machine 12 is cooled. According to the example of 1 is the electrical device 12 inside the hood (not shown in the drawing). In 1 the dryer section is shown without strings. The warm air under the hood heats the electrical device 12 , In this example case, there is the electrical device 12 from the observation unit of a web break detector used for monitoring the fibrous web. The observation unit monitors the fiber web from a short distance and triggers an alarm when the web breaks. There are several operational objects in the dryer section of the fiber web machine 14 with circulation lubrication, as here for example the bearings 48 the rollers 46 , which are lubricated and whose temperature is kept under control with the circulation lubrication. In the system according to the invention 10 Circulating lubricating oil is used to cool the electrical appliance 12 used.

Generally in paper machines as well as in the example in 1 for lubricating the bearings 48 and to maintain the temperature at a lubrication-appropriate value of circulating lubricating oil used by the bearings 48 from the circulation lubricating oil tank 34 with the pump 36 over the distributor 38 and further over the medium lines 16 is supplied. Preferably, the flow can be regulated in each individual medium line. Heat energy of the bearings 48 goes to the one lower Circulating lubricating oil over, which returns to the circulation lubricating oil tank 34 is directed. The circulating lubricating oil tank is preferably below the floor level 67 in the basement, where the circulating lubricating oil is stored at a temperature considerably lower than the hood temperature. The circulating lubricating oil tank serving cooling purposes has a very large volume, for example, 30 m ³ , so that the heat transferred from the insert object becomes the temperature of the circulating lubricating oil in the circulating lubricating oil tank 34 not significantly increased. In addition, the temperature of the tank can be regulated.

In the application of the invention causes the increased by only one or two degrees temperature of circulating lubricating oil no weakening of the cooling of the actual mission object, that is, for example, the camp. According to the invention, the circulating lubricating oil from the medium line 16 with the help of the coolant 22 to the electrical device 12 directed, from where the oil again over the medium line 16 to the mission object 14 and back to the tank 34 arrives.

According to 1 can in the circulation lubrication a distributor 38 which are used to the mission objects 14 flowing circulating lubricating oil on the supply lines 50 distributed. According to the invention, in particular, the flow line 50 in their entirety on the electrical device to be cooled 12 guided. In this way, taps in the medium line are avoided which cause flow losses and require additional control valves and flow dividing sensors. The return lines 52 can directly to the circulation lubricating oil tank 34 be guided. If required, the return lines can be routed through heat exchangers so that the heat from the insert objects can be used for heating purposes.

Further, the cooling means comprise 22 according to 1 interconnectors 28 and a housing 30 for the electrical device 12 , The housing 30 preferably has an insulation, with which the housing 30 surrounding warm air is kept as separate as possible from the electrical equipment. For example, the observation unit is located near rollers or cylinders 46 , so that the added length of the connecting lines is very small, that is preferably less than two meters. In this context, medium, connection flow line and return lines to understand piping in which the medium, preferably circulating lubricating oil, flows. Preferably, at least the heat transfer element is made of material that allows the most intense heat transfer from the electrical device to the circulating lubricating oil.

2 shows the cooling of the electrical device 12 inside the case 30 , which is shown in section. 2 is a principle drawing and the illustrated ratios may differ from the actual. In 2 are the case 30 and the electrical device deviates from 1 shown horizontally. As in 1 is also the electrical device 12 from an observation unit, the LEDs 40 , a sensor 41 for reflected light and its control unit 42 contains. The aforementioned parts are on carrier plates 44 and 44 ' mounted, which consist of good heat conducting material, for example aluminum. Below the carrier plate 44 is preferably a Peltier element 24 for additional cooling of the LEDs 40 and the sensor 41 attached. The carrier plates 44 and 44 ' can be separated from each other as the LEDs 40 and the sensor 41 require more cooling than the control unit 42 , and thus there is a possibility that under the control unit 42 located carrier plate 44 ' with the heat transfer element 47 to cool. These different solutions of the drawing can be used individually in different applications, that is only the Peltier element or only the heat transfer element. It is generally desirable to maintain the LEDs and sensors at a temperature of 45 ° C or below, while the controller can tolerate up to 75 ° C.

If the cooling requirement is low, the cooling of the electrical device can be carried out with the bare heat transfer element. If any electrical device requires a lower temperature than can be achieved with the mere heat transfer element, a Peltier element may be used in addition to this. The cooling can also be done alone with the Peltier element, ie without heat transfer element.

In the case 30 is the circulating lubricating oil flow through the connecting lines 28 passed, in turn, to the medium line 16 are connected. The connection lines 28 can be attached to the bottom of the peltier element 24 and to the underside of the carrier plate 44 ' be joined. The Peltier element is preferred 24 between the carrier plate 44 and the connecting lines 28 attached. In this way, the heat from the LEDs 40 and the sensor 41 over the carrier plate 44 using the Peltier element 24 on the in the connecting line 28 transferred circulating lubricating oil. Accordingly, also heat from the control unit 42 over the carrier plate 44 ' and the heat transfer element directly on the in the connecting line 28 transferred circulating lubricating oil. The lubricating oil transports the heat away from the electrical device 12 , In conjunction with the Peltier element 24 Also, a heat pipe can be used to transfer heat.

According to 2 is the electrical device 12 from a housing 30 Surrounded by the electrical device 12 to protect against high temperatures of the surrounding area. For example, because of the extremely high air temperature (eg, 100 ° C) and humidity (eg, 97%) under the hood, the condensation of moisture on the surfaces to be cooled is a problem. This problem can be avoided by putting in the case 30 a small air flow of 0.1-5.0 m / s, preferably 0.5-1.0 m / s causes, which over the opening 45 of the housing is derived to the outside. In the embodiment described here, this opening exists 45 from the for the LEDs and the sensor on the housing 30 trained opening 45 , This air flow can be supplied to the housing 30 over the entrance opening 74 while being able to warm up sufficiently at the connecting lines. In this way, air is released from the housing 30 passed without the moisture absorbed by the air reaches the dew point and immediately when leaving the housing 30 compressed over the opening to a fog disturbing the observation. The air flow can be generated, for example, with a small fan or the like, by pneumatics or by gravity. In this context, no means for generating the air flow are shown here.

The Peltier element 24 is used in this embodiment for cooling the LEDs 40 and the sensor 41 to a temperature lower than the temperature of the circulating lubricating oil. The temperature of the circulating lubricating oil may be, for example, 60 ° C, so that with direct cooling as in the control unit 42 No lower temperature of the electrical device can be achieved when the temperature difference goes to zero. When using a Peltier element, a heat transfer can be achieved by means of electric current, wherein heat can be transferred from a colder object to a warmer object. In this example here it means that the LEDs 40 and the sensor 41 to a value below the recirculating lubricating oil temperature of 60 ° C, for example to 40 ° C, can be cooled.

This makes it possible to use (even) more advantageous components in the LEDs and sensors, because the temperature of the electrical device can now be kept at a low level under all conditions. The Peltier element 24 is only used when the temperature of the electrical device is to be lowered to a value below the temperature of the circulating lubricating oil.

Preferably, the system comprises control means with which the power supply of the Peltier element 24 is turned on when the temperature of the electrical device is substantially equal to the temperature of the circulating lubricating oil. By "substantially" here is meant a temperature difference in which the heat transfer from the electrical device to the circulating lubricating oil takes place only extremely slowly. The temperature difference may be, for example, 1-10 ° C, preferably 2-6 ° C.

In 2 only one of the possible embodiments of the system according to the invention is shown, and it is understood that the placement of the parts can vary considerably depending on the application object. The system according to the invention can also be realized without a Peltier element. But it can also be used a multi-level Peltier element, which then gives a larger temperature difference. It is also possible to control the cooling power by means of current control.

3 shows a schematic drawing of the Peltier element 24 in partially cut form. The Peltier element 24 can have two separate ceramic plates 60 and 62 include, between which there is a temperature difference. The ceramic plates 60 and 62 are through semiconductors 65 attached to each other. Between the semiconductors 65 and the ceramic plates 60 . 62 can be a glue surface 72 , For example, silicone grease can be arranged. The semiconductors 65 are separate parts that can be arranged in rows and columns. There are two types of semiconductors 65 : p-semiconductors 70 and n-semiconductors 68 , In the ceramic plates 60 and 62 electric current is passed; the one of the plates 60 serves as a negative pole 64 , the other plate 62 as positive pole 66 of the circuit. The juxtaposed semiconductors 65 are connected in series so that the current in the semiconductors 65 alternating from an n-type semiconductor 68 to a p-type semiconductor 70 and a ceramic plate 60 and 62 flows to the other.

For example, the current in the circuit flows from the negative pole 64 in the fitting to the surface to be cooled ceramic plate 60 and along the n-type semiconductor attached thereto 68 in the applied to the heat receiving surface ceramic plate 62 , From there the current continues to flow to that with the n-type semiconductor 68 series-connected p-type semiconductors 70 , which returns the current back to the adjacent to the surface to be cooled ceramic plate 60 passes. In this way, the current flows alternately between the voltage applied to the surface to be cooled ceramic plate 60 and the heat-absorbing surface adjacent ceramic plate 62 , The n-semiconductors 68 transport heat in the current direction, the p-type semiconductors 70 again in the opposite direction. In this way, the heat migrates from the surface to be cooled to the heat-receiving surface.

The Peltier element 24 can have a power of 10-500 W, preferably 50-150 W depending on the object of use. The Peltier element 24 may be single or multi-stage, that is, it may have a plurality of ceramic plate levels and between these semiconductor layers located one above the other. The multi-stage element achieves a higher cooling capacity. For example, with one level of electrical equipment, a temperature drop of 30 ° C can be achieved. The rules can be easily done with direct current.

The system according to the invention can be used for cooling electrical appliances in operational objects in which a liquid circulating lubricant, preferably oil, is available. Alternatively, water can be used as the cooling medium, but then a separate thermal control unit is required. A particularly favorable use object in the dryer section of the fiber web machine is the cooling of the observation units used to display web breaks on bare rolls or cylinders. Blanke rolls heat up quickly when web breaks, increasing the need for cooling the electrical equipment.

The system according to the invention can also be installed in existing paper machines making small changes to the medium lines. In the present application, fibrous web machine is to be understood as meaning a paper, board or tissue machine or a pulp drying machine.

When electrical device to be cooled is any electrical device exposed to any high ambient temperature, preferably an electrical device used for optical measurement, ultrasonic measurement or mechanical position measurement. Electric motors, for example, can also be cooled in this way.

According to one embodiment, a plurality of juxtaposed electrical devices to be cooled can be connected to the feed leading to an application object, provided that the temperature increase of the circulating lubricating oil remains moderate. The circulation lubricating oil flow rate in the cooling means may be, for example, 0.1-10 l / min, preferably 1-3 l / min, but is highly dependent on the object of use.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• FI 118274 [0004]

Claims (10)

System ( 10 ) system for cooling an electrical device in a fiber web machine ( 10 ), which is an electrical appliance ( 12 ), Medium lines ( 16 ) for feeding medium to an insert object ( 14 ) in the fiber web machine and cooling means ( 22 ) for conveying the medium from the medium line ( 16 ) on or in the electrical device ( 12 ) for cooling the same with the medium, characterized in that the medium circulating lubricating oil for the insert object ( 14 ) in the fiber web machine. System according to claim 1, characterized in that the to the 14 ) in the fiber web machine leading medium line belonging feed line ( 50 ) for cooling the electrical device ( 12 ) in their entirety to the electrical appliance ( 12 ) and from there back to the mission object ( 14 ) in the fiber web machine leading medium line ( 16 ) is guided. System according to claim 1 or 2, characterized in that the cooling means ( 22 ) Connecting cables ( 28 ) for conducting circulating lubricating oil from the medium line ( 16 ) in or on the electrical device ( 12 ) and back into the medium line ( 16 ) as well as a housing ( 30 ) for isolating the electrical device ( 12 ). System according to claim 3, characterized in that for the removal of moisture inside the housing ( 30 ) an air flow is brought into effect, which via an opening ( 45 ) in the housing ( 30 ) is derived to the outside. System according to one of claims 1 to 4, characterized in that the cooling means ( 22 ) at least one for transmitting heat from the electrical device ( 12 ) in the circulating lubricating oil Peltier element ( 24 ) configured to turn on when the temperature of the electrical appliance ( 12 ) is substantially equal to the temperature of the circulating lubricating oil. System according to claim 5, characterized in that the Peltier element ( 24 ) is adapted to only a part of the electrical appliance ( 12 ) to cool. System according to claim 5 or 6, characterized in that the Peltier element ( 24 ) has a power of 10-500 W, preferably 50-150 W. System according to one of claims 1 to 7, characterized in that the electrical device ( 12 ) is an optical measuring unit, an ultrasonic measuring unit or a mechanical position measuring unit. System according to one of claims 1 to 8, characterized in that the circulating lubricating oil flow rate in the cooling means ( 22 ) 0.1-10 l / min, preferably 1-3 l / min. System according to one of claims 1 to 9, characterized in that the circulating lubricating oil for lubricating the bearings ( 48 ) belonging to the fiber web machine rollers ( 46 ) is circulating lubricating oil.

Images