WO2016113460A1

WO2016113460A1 - A conveyor system

Info

Publication number: WO2016113460A1
Application number: PCT/FI2015/050957
Authority: WO
Inventors: Mika Lohtander; Leevi PAAJANEN; Tapani SIIVO; Antti JORTIKKA; Hannu YLISIURUA; Emma PAASONEN; Jyrki MONTONEN
Original assignee: Lappeenrannan Teknillinen Yliopisto
Priority date: 2015-01-15
Filing date: 2015-12-30
Publication date: 2016-07-21
Also published as: FI126670B; FI20155026A; EP3245152A1

Abstract

A conveyor system comprises a conveyor car (102) movable in a conveyor shaft (101), an electrical drive (103) for moving the conveyor car, and a cooling system for cooling the electrical drive. The cooling system comprises a heat transfer device (104) for transferring heat from cooling fluid to the surrounding air and equipment for circulating the cooling fluid between the electrical drive and the heat transfer device. The heat transfer device is located in an air-flow channel (105) connected to the conveyor shaft and arranged to conduct air moved by the conveyor car when the conveyor car is moving. Thus, the movement of the conveyor car is utilized for cooling the electrical drive because air-flow through the heat transfer device is at least partly caused by the movement of the conveyor car.

Description

A conveyor system

Technical field

The disclosure relates generally to a conveyor system that can be for example an elevator system or any other conveyor system where a conveyor car is movable in a vertical, horizontal, inclined, or otherwise positioned conveyor shaft. More particularly, the disclosure relates to cooling an electrical drive of a conveyor system.

Background

In many cases a conveyor system comprises a conveyor shaft, a conveyor car movable in the conveyor shaft, an electrical drive for moving the conveyor car, and a cooling system for cooling the electrical drive. The conveyor system can be for example an elevator system or any other conveyor system where the conveyor car is movable in a vertical, horizontal, inclined, or otherwise positioned conveyor shaft. The electrical drive comprises an electrical motor for moving the conveyor car and a frequency converter or another supply device for driving the electrical motor in a controllable way. The cooling system can be an open cooling system where the surrounding air is blown to the electrical motor and to the supply device. In many cases, the cooling system is however a closed circulation cooling system in order to avoid accumulation of dust and/or other impurities on cooling surfaces of the electrical motor and the supply device. A closed circulation cooling system comprises typically one or more heat transfer devices for transferring heat from cooling fluid to surrounding air and equipment for circulating the cooling fluid between the electrical drive and the one or more heat transfer devices. The cooling fluid can be for example water in which case the heat transfer device is a radiator for transferring heat from the water to the surrounding air. It is also possible that the cooling fluid is air or some other gas in which case the heat transfer device is a gas-to-air heat exchanger. The closed circulation cooling system comprises typically one or more fans for blowing air to the one or more heat transfer devices. In order to minimize the energy consumption of the conveyor system, the operating times of the fans should be as short as possible. Furthermore, the overall operat- ing life-time of the fans is limited especially in cases where the fans have grease lubricated encapsulated bearings.

Summary

The following presents a simplified summary in order to provide a basic under- standing of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments of the invention.

In accordance with the invention, there is provided a new conveyor system that can be for example an elevator system or any other system where a conveyor car is movable in a vertical, horizontal, inclined, or otherwise positioned conveyor shaft. A conveyor system according to the invention comprises: - a conveyor shaft,

- a conveyor car movable in the conveyor shaft,

- an electrical drive for moving the conveyor car, and

- a cooling system for cooling the electrical drive.

The cooling system comprises a heat transfer device for transferring heat from cooling fluid to surrounding air and equipment for circulating the cooling fluid between the electrical drive and the heat transfer device. The heat transfer device is located in an air-flow channel connected to the conveyor shaft and arranged to conduct air moved by the conveyor car when the conveyor car is moving. Therefore, the air-flow through the heat transfer device is at least partly caused by movement of the conveyor car in the conveyor shaft and thus the movement of the conveyor car is utilized for cooling the electrical drive.

In a conveyor system according to an exemplifying and non-limiting embodiment of the invention, the cooling system comprises two or more heat transfer devices in two or more air-flow channels connected to the conveyor shaft in order to effectively utilize the air movement caused by the conveyor car for cooling the electrical drive.

A number of exemplifying and non-limiting embodiments of the invention are de- scribed in accompanied dependent claims.

Various exemplifying and non-limiting embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying and non-limiting embodiments when read in connection with the accompanying drawings.

The verbs "to comprise" and "to include" are used in this document as open limitations that neither exclude nor require the existence of unrecited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", i.e. a singular form, throughout this document does not exclude a plurality.

Brief description of the figures

Exemplifying and non-limiting embodiments of the invention and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which: figure 1 illustrates a conveyor system according to an exemplifying and non- limiting embodiment of the invention, and figure 2 illustrates a conveyor system according to another exemplifying and non- limiting embodiment of the invention.

Description of the exemplifying embodiments Figure 1 shows a schematic a section view of a conveyor system according to an exemplifying and non-limiting embodiment of the invention. In this exemplifying case, the conveyor system is an elevator system. The section plane is parallel with the xz-plane of a coordinate system 190. The conveyor system comprises a sub- stantially vertical conveyor shaft 101 that is typically a part of a building e.g. a block of flats. The conveyor system comprises a conveyor car 102 movable in the conveyor shaft 101 and an electrical drive 103 for moving the conveyor car. The electrical drive 103 comprises an electrical motor 106 for moving the conveyor car 102 and for example a frequency converter 107 for driving the electrical motor in a controllable way. In this case, the electrical motor 106 can be for example an induction motor or a permanent magnet synchronous motor. The conveyor system comprises advantageously a counterweight so that the electrical drive 103 has to overcome only the weight difference between the conveyor car 102 carrying a possible load and the counterweight. The counterweight is not shown in figure 1 but the counterweight can be behind the wall of the conveyor shaft 101 that is parallel with the xz-plane of the coordinate system 190.

The conveyor system comprises a cooling system for cooling the electrical drive 103. The cooling system comprises a heat transfer device 104 for transferring heat from cooling fluid to the surrounding air and equipment for circulating the cooling fluid between the electrical drive 103 and the heat transfer device 104. The heat transfer device 104 is located in an air-flow channel 105 connected to the conveyor shaft 101 and arranged to conduct air moved by the conveyor car when the conveyor car is moving. Thus, the air-flow through the heat transfer device 104 is at least partly caused by the movement of the conveyor car 102. In figure 1 , a dashed-line arrow depicts the air-flow through the air-flow channel 105 when the conveyor car 102 is moving upwards and a dash-and-dot line arrow depicts the air-flow through the air-flow channel 105 when the conveyor car is moving downwards. In this exemplifying case, the cooling fluid is liquid, e.g. water, and the equipment for circulating the cooling fluid comprises a pump 1 10 and a piping 1 1 1 . The heat transfer device 104 is a radiator for transferring heat from the liquid to the surrounding air. In a conveyor system according to another exemplifying embodiment of the invention, it is also possible that the cooling fluid is gas, e.g. air, in which case the heat transfer device is a gas-to-air heat exchanger. A conveyor system according to an exemplifying and non-limiting embodiment of the invention comprises a blower 1 12 for boosting the air-flow in the air-flow channel 105. The conveyor system may comprise a controller and one or more meas- urement sensors for controlling the blower 1 12 at least partly on the basis of the temperature of the cooling fluid. The controller can be e.g. part of the frequency converter 107. A measurement sensor can be e.g. a temperature sensor for measuring the temperature of the cooling fluid. The blower 1 12 can be controlled for example so that the blower is activated when the temperature of the cooling fluid exceeds a pre-determined safety limit. The blowing direction of the blower 1 12 is advantageously controlled on the basis of the moving direction of the conveyor car 102 so that both the conveyor car and the blower are arranged to move air in a same direction in the air-flow channel 105. Figure 2 shows a schematic section view of a conveyor system according to an exemplifying and non-limiting embodiment of the invention. In this exemplifying case, the conveyor system is an elevator system. The section plane is parallel with the xz-plane of a coordinate system 290. The conveyor system comprises a substantially vertical conveyor shaft 201 , a conveyor car 202 movable in the conveyor shaft 201 , and an electrical drive 203 for moving the conveyor car. The conveyor system comprises advantageously a counterweight so that the electrical drive 203 has to overcome only the weight difference between the conveyor car 202 carrying a possible load and the counterweight. The counterweight is not shown in figure 2.

The conveyor system comprises a cooling system for cooling the electrical drive 203. The cooling system comprises heat transfer devices 204 and 208 for transferring heat from cooling fluid to the surrounding air and equipment for circulating the cooling fluid between the electrical drive 203 and the heat transfer devices. The heat transfer device 204 is located in an air-flow channel 205 connected to the conveyor shaft 201 and arranged to conduct air moved by the conveyor car when the conveyor car is moving. Correspondingly, the heat transfer device 208 is located in an air-flow channel 209 connected to the conveyor shaft 201 and arranged to conduct air moved by the conveyor car when the conveyor car is moving. Thus, the air-flows through the heat transfer devices 204 and 208 are at least partly caused by the movement of the conveyor car in the conveyor shaft 201 . In figure 2, dashed-line arrows depict the air-flows through the air-flow channels 205 and 209 when the conveyor car 202 is moving upwards and dash-and-dot line ar- rows depict the air-flows through the air-flow channels 205 and 209 when the conveyor car is moving downwards.

The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.

Claims

What is claimed is:

1 . A conveyor system comprising:

- a conveyor shaft (101 , 201 ),

- a conveyor car (102, 202) movable in the conveyor shaft, - an electrical drive (103, 203) for moving the conveyor car, and

- a cooling system for cooling the electrical drive, wherein the cooling system comprises a heat transfer device (104, 204) for transferring heat from cooling fluid to surrounding air and equipment for circulating the cooling fluid between the electrical drive and the heat transfer device, character- ized in that the heat transfer device is located in an air-flow channel (105, 205) connected to the conveyor shaft and arranged to conduct air moved by the conveyor car when the conveyor car is moving, an air-flow through the heat transfer device being at least partly caused by movement of the conveyor car.

2. A conveyor system according to claim 1 , wherein the cooling system com- prises at least one other heat transfer device (208) in at least one other air-flow channel (209) connected to the conveyor shaft and arranged to conduct air moved by the conveyor car when the conveyor car is moving.

3. A conveyor system according to claim 1 or 2, wherein the heat transfer device is a radiator for transferring heat from liquid to the surrounding air.

4. A conveyor system according to claim 1 or 2, wherein the heat transfer device is a heat exchanger for transferring heat from gas to the surrounding air.

5. A conveyor system according to any of claims 1 -4, wherein the electrical drive comprises an electrical motor (106) for moving the conveyor car and a frequency converter (107) for driving the electrical motor in a controllable way.

6. A conveyor system according to any of claims 1 -5, wherein the conveyor system comprises a blower (1 12) for boosting the air-flow through the heat transfer device (104).

7. A conveyor system according to claim 6, wherein the conveyor system comprises a controller and at least one sensor for controlling the blower at least partly on the basis of temperature of the cooling fluid.

8. A conveyor system according to claim 6 or 7, wherein the conveyor system comprises a controller for controlling a blowing direction of the blower (1 12) on the basis of a moving direction of the conveyor car (102) so that both the conveyor car and the blower are arranged to move the surrounding air in a same direction through the heat transfer device (104).

9. A conveyor system according to any of claims 1 -8, wherein the conveyor system is an elevator system where the conveyor shaft is substantially vertically positioned and the movement of the conveyor car is substantially vertical.