GB2046427A - Cooling system in mining machine - Google Patents

Abstract

A mining machine is provided with means for cooling the motors and other equipment provided on the machine for propelling the machine, said means comprising an electric motor, a refrigeration circuit (9) including a compressor (39) a condenser (45) and an evaporator (33) and a water cooling circuit (7) wherein water is pumped from a supply through cooling devices (3, 5) associated with the equipment to be cooled on the machine and through the evaporator of the refrigerant circuit. The evaporator is shown downstream of the cooling devices, but could be upstream. By providing an independent water cooling circuit, water normally used for dust suppression need only be sprayed into the mine during mining operations and it is not necessary to use this water when other tasks are performed by the machine in the mine for cooling purposes. <IMAGE>

Description

SPECIFICATION Mining machine This invention relates to mining machinery and in particular to mining machines provided with a device for cooling the motors and other equipment provided on the machines for propelling the machines, for operating the cutting head and for performing other tasks in a mine. The mining machines of this invention are particularly designed for underground use. The invention also relates to a method of cooling equipment on mining machines.

In the past, heat generated by the engines and other power sources provided on mining machines has been dispersed with the aid of water carried by the machine for dust suppression purposes. In other words, the water used to suppress dust when the machine is performing a cutting operation is firstly passed through one or more water jackets associated with the electric motors or other power source and through the hydraulic fluid cooling coils before being sprayed in the area of the cut, and this water is then taken away with the mined material.

Often, however, present day mining machinery, for example a roadheader, is utilised not just for a cutting operation but for various other operations such as arch fitting and for such operations, dust suppression is not required. However, the heat generated by the machines' power system still has to be dispersed. At present, the cooling water from the supply for dust suppression has been used, and has then mereiy been cast onto the floor of the mine, thus presenting various problems.

Attempts have been made in the past to overcome this problem by using a small air blast type of radiator unit on the mining machine so that cooling water can be recycled but as more and more mechanisation is introduced into the mines and as the machines increase in size and therefore require more powerful motors and ancillary equipment, these air blast units have provided inadequate.

According to the present invention, we provide a mining machine having at least one power source thereon which is cooled by means of a liquid, e.g.

water, cooling system, the water cooling system including a water supply, a refrigerant evaporator and means for pumping the water from the supply through the said at least one power source and the evaporator and returning it to the supply, and wherein a separate closed cooling circuit is provided, the cooling circuit having a refrigerant therein and including a compressor to turn the refrigerant into a high pressure gas, a condenser to convert the gas into a high pressure liquid and the refrigerant evaporator, said liquid refrigerant being injected into the refrigerant evaporatorthrough an expansion valve whereby it absorbs heat from the hot water passing through the evaporator and becomes a refrigerant gas again, whereupon it is then drawn back through the compressor for a subsequent cycle.

In one construction, a water pump pumps water from a tank, through a water jacket of an electric motor and through a hydraulic fluid cooling coil, then through the evaporator where the water is cooled, and then back to the tank. Alternatively, if the evaporator is of a design which can withstand a high water pressure, it may be upstream of the power source(s) to be cooled.

Preferably, the mining mchine is provided with an extra electric motor having a double ended drive shaft, one end of the drive shaft being coupled to the refrigerant compressor and the opposite end being coupled to the water circulating pump.

Preferably, the pump also has a double ended shaft, the end of the shaft remote from the coupling to the motor shaft having a fan mounted thereon to induce a flow of air across the condenser.

Preferably, a water header tank is provided at a high level in the overall casing for replenishing water lost from the water cooling system and two air cooled condensers are provided, one on each side of the water pump.

A mining machine in accordance with the present invention is now described by way of example with reference to the accompanying drawings, in which Figure la is a schematic view showing a water cooling circuit; Figure 1b is a similar view of a refrigerating circuit on the mining machine; Figure 2 is a side elevation, to a larger scale, with parts broken away, showing water cooling plant for the machine of Figure 1; Figure 3 is a part section on the line B-B of Figure 2,and Figure 4 is an end elevation.

Referring to the drawings, a mining machine 1 of largely standard construction has one or more power sources, e.g. one or more electric and/or hydraulic motors provided respectively with jackets 3 and hydraulic fluid cooling coils. A water cooling circuit 7 is associated with the or each water jacket 3 and/or the or each cooling coil 5 and a refrigeration circuit 9 is provided to cool the water in the circuit 7.

The refrigeration circuit 9 is all located within a casing 11 in which is also located an electric motor 13 for circulating the fluid in each circuit. The motor 13 is of a type approved for use in coal mines and has a double ended drive shaft. One end 17 of the drive shaft is connected by a coupling 19 to one end 21 of a drive shaft of a water pump 23, the other end 25 of the drive shaft having a fan 27 mounted thereon, the fan being located adjacent an air exit grill 29 in the casing 11.The pump 23 forms part of the circuit 7 and pumps water from a water tank 31, through the or each hydraulic fluid cooling coil 5 and/orthrough the water jacket 3 around the or each motor, and is then circulated through a heat exchanger associated with an evaporator 33 of the refrigeration circuit 9 so that the water is cooled, and it is then returned to the tank 31. The cooled water is then circulated again and again. A header tank 37 may be provided to top up tank 31.

The refrigerant circuit 9 includes a compressor 39 which is driven through a coupling 41 by the other end 43 of the motor drive shaft. The compressor 39 compresses refrigerant in the refrigeration circuit 9 into a high pressure gas which is then passed through condensers 45 located in the bottom of the casing 11 on either side thereof which are cooled by air drawn over them by the fan 27. The condensers convert the high pressure gas into a high pressure liquid and this liquid is then injected through an expansion valve 47 into the refrigerant evaporator 37 where it rapidly absorbs heat from the hot water in the heat exchanger, thereby turning back into a gaseous state and at the same time cooling the.

water. The gaseous refrigerant is then sucked back through the compressor 39 ready for a subsequent cycle.

Claims (9)

1. A mining machine having at least one power source thereon which is cooled by means of a liquid cooling system, the liquid cooling system including a supply of liquid, a refrigerant evaporator and means to pump the liquid from the supply through the said at least one power source and the refrigerant evaporator and for returning itto the supply, and wherein a separate closed cooling circuit is provided, the cooling circuit having a refrigerant therein and including a compressor to turn the refrigerant into a high pressure gas, a condenser to convert the gas into a high pressure liquid and the refrigerant evaporator, said liquid refrigerant being injected into the refrigerant evaporator through an expansion valve whereby it absorbs heat from the hot water passing through the evaporator and becomes a refrigerant gas again, whereupon it is then drawn back through the compressor for a subsequent cycle.

2. A mining machine as claimed in claim 1 wherein a water pump pumps water from a tank, through a water jacket of an electric motor and through a hydraulic fluid cooling coil, then through the evaporator where the water is cooled and then back to the tank.

3. A mining machine as claimed in claim 1 wherein the evaporator is upstream of the or each power source to be cooled.

4. A mining machine as claimed in claim 1,2 or 3 and further comprising an electric motor having a double ended drive shaft, one end of which is coupled to the refrigerant compressor and the opposite end of which is coupled to the liquid circulating pump.

5. A mining machine as claimed in claim 4 wherein the pump also has a double ended shaft, the end of the shaft remote from the coupling to the motor shaft having a fan mounted thereon to induce a flow of air across the condenser.

6. A mining machine as claimed in claim 5 wherein a water head tank is provided at a high level in the machine.

7. A mining machine as claimed in any one of the preceding claims wherein two air cooled condensers are provided, one on each side of the pumping means.

8. A mining machine substantially as hereinbefore described with reference to the accompanying drawings.

9. Amethod of cooling equipment on mining machines, said method being substantially as hereinbefore described with reference to the accompanying drawings.