AU662334B2 - Method for supplying underground workings with cooling and refrigeration installation having a three-chamber tube charger - Google Patents

Description

I y I 662334

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT 4 9.

*9 9 #99999 9 9* 99 9 9* 99 99 t 9, .9,9 1 6* 9 4 99 Applicant(s): Invention Title: SIEMhG TRANSPLAN GMBH METHOD FOR SUPPLYING UNDERGROUND WORKINGS WITH COOLING AND REFRICERATION INSTALLATION HAVING A THREE -CH2U0VMR TUBE

CHARGER.

The following statement is a full description of this invention, including the best method of performing it known to me/uts: 1#A j irn 1' -2- The present invention relates to a method for supplying underground workings with the cooling required primarily for the air-conditioning technology measures in mining operations, which is produced above the surface and is introduced by way of a primary stream down through the mine-shaft and there it is heated by the secondary stream supplying the cooling equipment at the working site, after which it is returned to the surface for re-cooling, in which case coc~ing equipment provided with evaporator and condenser is utilised for the transfer from the primary stream to the secondary stream. The invention also relates to cooling equipment, with components underground and above-ground linked 1r together by way of the primary stream, where, in the above-ground stream there is a wet-air preliminary cooler and cooling equipment and, additionally at the same time, in the secondary stream, underground, cooling equipment and a S pressure-change device are incorporated.

With the increasing average depths of mining and augmented local-site 15 extraction, there is unavoidably an increase in the average mining temperature and also of the electrical equipment. With this is associated the impetus for adoption of air-conditioning measures. The cooling capacity required for this is produced, on an ever-increasing scale, by centralised cooling equipment and, above all, most certainly with the use of so-called combination installations.

20 These types of combination installations utilise above-ground cooling equipment and underground cooling equipment which are connected to a primary circuit or primary circulatory system. Above-ground there is a preliminary wet air cooler and one or several units of cooling equipment and, underground, there is a high-pressure/low-pressure heat exchanger and also cooling equipment units.

These underground cooling equipment components with high-pressure condensers transfer their cooling effect to a cooling medium, mainly to water in a swondary circulatory system, by way of which the cooling equipment at the working sites to be cooled are supplied. The pri.Aary and secondary circulatory i 1 If -3systems are dosed systems which come into indirect contact with one another only in the region of the underground installation components.

In the known methods, the cooling medium, preferably water in above-ground installation units, of the primary circulatory system is cooled to 3 'C and it is then forwarded down through the underground shaft duct to the highpressure/low-pressure heat exchanger on the high-pressure side at approximately 160 bar. The high-pressure/low-pressure heat exchanger is supplied on the lowpressure side with by the heated secondary stream returning from the mine working site. A portion of the heat of the secondary stream is transferred to the °"10 primary stream by convection and conduction. The primary stream is warmed by this to approximately 19 'C which is subsequently conveyed at this temperature to the underground cooling equipment units, to take up the condensation heat arising from the cooling process and then is then transported through the mineshaft return pipeline to above-ground. The temperature in the mine-shaft return S 15 pipeline is approximately 32.6 OC. Because the underground primary stream is S under high hydrostatic pressure, the condensers on the water side of the cooling equipment units must be designed as high-pressure containers. These highpressure condensers represent a not-inconsiderable investment outlay. In the present state of the art, the primary stream above-ground is forwarded through t 20 a wet air cooling system, where the condensation heat taken up underground is extracted from the cooling medium and conducted away to the atmosphere by a stream of air blown through the system. In the above-ground cooling equipment units, the primary stream is subsequently cooled again to its preliminary temperature of approximately 3 C. The secondary stream issuing from the highpressure/low-pressure heat exchanger flows through the evaporator of the cooling equipment and can be cooled overall to approximately 3 C, to then be conveyed as cooling medium to the appropriate working sites at the longwall face and to other locations as required.

II I m uiI :l 4 Because of the bivalent utilisation of the primary stream (transport of cooling to underground on the forward cooling run; transport of heat to above-ground on the return run), a large temperature difference of 30 to 32 0 C develops between the forward and return runs. Because of this, the amount of flow in the primary circulatory system can be kept comparatively small. These high temperature differences are not reached in the secondary circulatory system (but only approximately 18 0 C, so thait, for technical reasons, the amounts of medium flowing the secondary and primary streams must be substantially different. The disadvantage here is, in particular the high cost of installation of the high-pressure/low-pressure heat exchanger with its unfavourable transfer of the cooling effect as well as the unfavourable overall exploitation of the installed cooling equipment.

The invention therefore has to solve the problem of providing an installation with which, while maintaining a 4 "wide temperature range with simplification of the installation components, improved exploitation of the system may be achieved.

In accordance with the present invention there is envisaged a method for supplying underground operations with a cooling medium primarily for air-conditioning in mining operations, in which said cooling medium is produced above I *ground and is introduced by way of a primary stream down through a mine-shaft where it is heated by a secondary stream performing a cooling function at a working site, S after which it is returned to the surface for re-cooling, wherein, cooling equipment including an evaporator and a condenser is utilized at the working site for heat transfer ttc from the primary stream to the secondary stream, and t wherein said secondary stream, after it has performed its cooling function at the working site, but before flowing to i 4 Ul taltlennelkeepl1B518.921 3.7

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.I im I ,i 4a the cooling equipment at the working site, is subdivided into a first part-stream and a second part-stream, and wherein said first part-stream takes up heat from the condenser and then, in interchange with the primary stream is sluiced into a high-pressure system and conveyed to above-ground, and further wherein said second part-stream is cooled in the evaporator and then, in conjunction with the cooling medium of the primary stream issuing from the high-pressure system at a reduced pressure, it is pumped to equipment performing the cooling function of the working site.

There is also envisaged a refrigeration installation with cooling equipment components underground and above-ground which are linked together by way of a primary stream, wherein in the above-ground primary stream there is a wetair preliminary cooler and cooling equipment and additionally, in a secondary stream underground, cooling equipment and pressure-change device are utilized wherein a pressure-change unit is configured as a three-chamber tube charger unit which is designed for interchange of a first part-stream of the secondary stream with the primary stream I and for forwarding it to above-ground, and wherein condensers of the underground cooling equipment have the first part-stream flowing through them, while a second part-stream of the secondary stream flows through the a evaporators.

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The present invention makes if possible, first of all, to achieve a substantially improved exploitation of the capacity of the installation, because it is possible to dispense with the use of two separate circulatory systems since the primary stream coming from above-ground, after reduction of pressure, complements the part of the secondary stream which, in interchange after corresponding heating, is pumped to above-ground. The other part-stream is cooled to such an extent in the existing cooling equipment that a cooling medium, which has been entirely cooled down to 3 is conveyed through the second circulatory system towards the working site. In this way it is possible to dispense with the unfavourable transfer of the cooling effect through the high-pressure/lowit pressure heat exchanger by convection and conduction. There is thus practically It 14* no temperature loss, without it coming to an overlapping of the lowpressure/high-pressure system in the interchange equipment in the primarystream/secondary-stream transition zone. Much rather than this, an unequivocal separation is maintained between the medium in the low-pressure system and the medium in the high-pressure system, so that it is also possible to operate at a higher return-flow temperature, which leads to improved performance of the above-ground cooling equipment installation.

In accordance with an expedient embodiment of the invention, provision is made for approximately 40% of the secondary stream to be passed through the C underground evaporator and cooled to approximately 3 with simultaneous heating of approximately 60% of the secondary stream flowing through the condensers from approximately 21 °C to approximately 35 and is pumped away from the site with the water from the primary stream under reduced pressure. Therewith, the quantity of the primary stream remains fixed, which amounts to 60% of the secondary stream. This represents a very favourable loading of the underground cooling equipment, which can be designed in a correspondingly favourable manner. The relative small-volume streams in the i ;i -6underground cooling equipment contribute to a reduction of the resistance of flow and consequently to a reduction of the energy costs.

With the utilisation of appropriate aggregates, and in the present case a threechamber tube charger unit, the interchange between primary stream an: secondary stream as described previously is possible in the underground region, in which case the correspondingly heated portion of the secondary stream it conveyed to above-ground. Along with this, it is an advantage for the underground part-stream leaving the underground condensers to be forwarded, with the assistance of the existing hydrostatic pressure of the primary stream 10 and a back-up pump, to the above-ground cooling units where it is cooled to a primary stream having a temperature of 2.5 The heated part-stream of the secondary stream corresponding in volume to the primary stream is interchanged in this way, in which case frictional losses which arise are compensated for by the pump which, because of the small losses, need only have a correspondingly low capacity. The remainder of the forwarding procedure is effected by the interchange of the primary stream and the heated part-stream of the secondary stream.

4 1* *9 '40 #4 k@ 4 64 4 1 41 1(11 For carrying out the method, use is made of a refrigerating installation in which 20 the pressure-change aggregate is configured as a three-chamber tube charger unit which is designed for interchange of a first part-stream of the hot secondary stream with the cold primary stream and for forwarding it to above-ground, and for the condensers of the underground cooling equipment to have the first partstream flowing through them, while the second part-stream of the hot secondary stream flows through the evaporators. The three-chamber tube charger unit is not a heat exchanger in the technical methodology sense, instead of which it is a sluice by means of which water from the low-pressure system can be introduced into the high-pressure system, and vice-versa, without interruption of the i -i4 i -7continuity of the flow. Under these conditions, this type of three-chamber tube charger unit has the capability of maintaining an unequivocal separation of the water in the low-pressure system from that in the high-pressure system. For this reason the three-chamber tube charger unit is admirably suitable for utilisation in such combination refrigeration installations. Three-chamber tube charger units are already known from the German Patents DBP 15 56 735, 17 56 591 and 24 57 943. These known three-chamber tube charger units possess tubular pipelines utilised as tube chambers, which are disposed horizontally. In this case the continuous current principle is employed. With the use of the continuous direct current principle, the chambers are filled from the same side with ore pulp and subsequently subjected to water under high pressure. On the contrary, with the use of the counter-current principle, the water under high pressure is introduced on the side of the system opposite to the filling side for the pulp.

.These three-chamber tube charger units are used primarily for transport of coal and ore, where they achieve a forwarding of 96% compared with only 65% in S the use of two-chamber tube charger units.

#tit According to an expedient implementation of the inventive refrigeration 4. installation, a pump is installed downstream of the underground cooling equipment to compensate, above all, for frictional losses and it is built into the 20 mine-shaft return pipeline. With the use of this pump, it is possible, in conjunction with the three-chamber tube charger unit, to raise the required amount of heated water to the above-ground level, for the purpose of using the above-ground cooling equipment to cool it again and then to return it underground. Because the pump is only needed to compensate for frictional losses, it can be of correspondingly small capacity.

In order to be able to subdivide the secondary stream in correct proportions, as provided for in the method in accordance with the present invention, provision d 1 -7 i 8 is made for installation in the hot secondary stream of a volume divider which is designed to subdivide said secondary stream in the ratio of 60 40. In this case the volume divider may be adjustable so that this ration may be adjusted to be higher or lower within a certain range, depending upon which specified ratios are required to be taken into consideration. The subdividing of the secondary stream, and therewith the resultant lessened load on the underground cooling equipment, leads not only to advantages in the layout of the equipment, but also to lower energy costs due to the lesser energy requirements for the pump.

It is especially advantageous for the underground cooling installations to be equipped with low-pressure condensers, which is made possible because the condensers of the underground cooling installations are no longer affected by the primary stream but only by the subdivided secondary stream in the normal pressure region. The condensers are thus correspondingly less expensive and simple in construction. In addition, it is only one of the aggregates installed in the underground workings which is subjected to the effect of the water under high pressure which comes from above-ground, whereas, in the present state of the art, the entire underground refrigeration installation must be correspondingly equipped.

25 The most highly favourable temperature spread and therewith also a favourable return flow temperature may be achieved if at least two underground cooling units are provided whose condensers are designed to warm the first part-stream from 21 0 C to 28.3 0 °C and 34.9 0 C, whilst their 30 evaporators are designed to cool the second part-stream from 21 0 C to 11.3 0 C and 3 0 C respectively. In this way, water with its temperature raised to almost 35 0 C is supplied to the above-ground cooling installation and, above all, to the wet-air preliminary cooling system, so that the wet-air preliminary cooler can be exploited more profitably.

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*ta9 9r 9 O 0 .9 9 9 C Ci-- ~i -9- The invention is especially distinguished by the fact that, in the three-chamber tube charger system, temperature losses practically never occur. A further advantage is that the wide spread of temperature in the primary circulatory system is fully maintained. The invention improves upon the method of operation of the refrigeration installation to such an extent that, because of the avoidance of the high temperature losses, an increased primary return flow temperature, and therewith a further reduction oi the primary stream, may be achieved. In conjunction with this there is a reduction of energy required to operate the pump. Because of the increased primary return flow temperature above-ground, there is improvement of the performance of the wet-air preliminary cooler. Here it is possible to dissipate the increased capacity into the atmosphere in a cost-effective operating way. The burden is removed from the downstream cooling installation. This brings about a substantial lowering of the above-ground operating costs, combined above all with the reduction of the energy costs. Exclusively low-pressure water is supplied to the evaporators as o well as to the condensers of the underground cooling installations. Because of this, high-pressure condensers are no longer required. The investment costs are I reduced. Because of the decrease in volume of the stream flowing through the Sunderground evaporators and condensers, and also because of the elimination of flitt the high-pressure/low-pressure heat exchanger, the flow resistance is reduced to S: a very great extent. This becomes evident in the significant savings in the energy a t costs.

Further details and advantages of the object of the invention may be gleaned from the following description with reference to the accompanying drawings in which an example of a preferred embodiment is depicted with the necessary details and individual components.

Ii I Fig. 1 is a diagram of a refrigeration installation with components underground and above-ground.

Fig. 2 is a flow diagram of a three-chamber tube charger.

Fig. 1 depicts the distribution of the installation components for the underground and above-ground regions, where the dividing plane is shown approximately in the middle with arrows pointing in opposite directions. The refrigeration installation has available, in the conventional manner, the wetair preliminary cooler located above-ground which is supplied with water at a temperature of 34.5 °C flowing from the underground installation. In the wet-air preliminary cooler a cooling of approximately 310 cubic metres of water per hour to approximately 21 °C takes place. This water having a temperature of 21 'C is then forwarded to the cooling equipment installation This water flows through the evaporator of the cooling equipment where it is cooled to 13.7 OC. Subsequently it is passed through the evaporator of the cooling 15 equipment to be cooled to 7.4 °C and then through the evaporator of the cooling equipmert to reach the end temperature of 2.5 This primary j stream is then conveyed down through the mine-shaft pipeline (11) to the underground installation.

\The cooling equipment 4, 6) respectively have a condenser in which the cooling medium is appropriately heated from 21 0 C to 32 C in order to be forwarded to the re-cooler This circulation is maintained by means of the pump The water to be cooled is conveyed to the wet-air preliminary cooler and the cooling equipment 4, 6) by way of the mine-shaft pipeline (12) in which the pump (13) is installed in order to raise this hot primary stream, where the main output from the three-chamber tube charger (15) is effected underground.

1 11 This three-chamber tube charger is supplied by the primary stream in which case the water at a temperature of 2.5 °C has a pressure of approximately 160 bar or the high-pressure side. In the three-chamber tube charger, the pressure on the primary stream is appropriately reduced and it is interchanged with one portion of the secondary stream which is corresponding conveyed to aboveground. The water leaving the three-chamber tube charger (15) through the outlet gate valve (14) is then mixed with the remaining portion of the secondary stream, which has been cooled in the cooling equipment (16, 17), and then conveyed to the usage site. The underground cooling equipment (16, 17) is each supplied with a condenser (18) and an evaporator (19).

SAfter the heating of the secondary stream (20) in the region of the usage site the secondary stream is forwarded by the pump (21) to the volume divider (24) where it is separated into part-streams (22 and 23) in the ratio of 60 I r The part-stream (23) passes through the evaporator (19) of each of the cooling 15 equipment units (16, 17) where it is cooled from 21 °C to 11.3 *C and then to 3 0 'C respectively. The appropriately cooled part-stream is then mixed with the appropriate portion of the primary stream which has issued from the three-chamber tube charger (15) and is then forwarded as the 100% mixture to lthe usage site (26).

I It The first part-stream downstream from the volur,:! divider is conveyed to the condensers (18) which are here configured as low-pressure condensers and heated first from 21 OC to 28.3 0 C and finally to 34.9 0 C. This heated part-stream (22) then arrives at the three-chamber tube charger where it is subjected to the appropriate high pressure and forwarded to above ground.

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r I -12- The three-chamber tube charger (15) is supplied on the high-pressure side (29) with the primary stream coming from above-ground, whereas the hot partstream (22) is introduced into the three-chamber tube charger (15) on the lowpressure side The cold primary stream leaves the three-chamber tube charger (15) on the low-pressure side at (28).

All of the named features, even those which can only be lea e drawings, are to be regarded as esseenial-ta e invention, on their own or in combi :111:;' Fig. 2 depicts a three-chamber tube charger which, accrding to Fig. 1, is located 10 between the above-ground cooling installation and the underground cooling V4 installation. It consists of three tube chambers (32, 38 and 39). These tube chambers (32, 38 and 39) are successively supplied with high-pressure cold water by the primary stream or the mine-shaft pipeline (11) and with low-pressure hot water from the secondary stream Because of this alternating switching, 15 a quasi-continuously flowing stream is achieved.

I i The principle of the three-chamber tube charger will be explained in greater detail with reference to one chamber.

For filling with low-pressure warm water from the secondary stream the gate valves (35 and 36) are first of all opened at the same time. The in-flowing warm water forces the low-pressure cold water, which was standing in this tube chamber into the secondary stream or the corresponding pipeline The filling procedure is ended when the warm water has reached the vertex The two gate valves (35 and 36) are then dosed. The tube chamber (32) has been loaded. The gate valves (33 and 34) are now opened and high-pressure cold water flows from the mine-shaft pipeline (11) through the gate valve (33) into gI..~ '1; 13 i ar the tube chamber in which case, at the same time, the low-pressure hot water which is present therein is forced into the mine-shaft pipeline (12) as high-pressure hot water, until the cold-water front has reached the vertex The gate valves (33 and 34) are now closed again and the chamber has its pressure reduced. The pressurereduction, valve (37) is provided for this purpose.

Following this, the gate valves (25 and 36) are opened again and the low-pressure hot water flows into the chamber until the hot-water front has reached the vertex (40) once again. The procedure as just described is then repeated all over again.

In Figure 1 of the drawings, each of the aboveground cooling units 4 and 6) include a piping system a compressor (42) and a throttle valve whilst each of the underground cooling units (16 and 17) each include a piping system a compressor (45) and a throttle valve (46).

In each of three above-ground coolings units (3, 4, 6) and both underground cooling units (16 and 17) the thermodynamic continuous cycle process usually runs as follows: Boiling refrigerant is in the evaporator, where it is evaporated and removes heat from the cooling medium and the material to be cooled which is conveyed through the evaporator that is, it produces cold. The vapour thus released is suctioned off by the compressor (42, 45) and compressed. The now highly superheated vapour enters the condenser, where first the superheating heat and then the condensation heat are drawn off, namely transferred to the medium moved through the condenser, while the refrigerant returns to the liquid state. The liquid refrigerant is now fed through the throttle valve (43, 46) and reduced in pressure to the original state, whereby its circuit is closed.

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Claims (9)

1. A method for supplying underground operations with a cooling medium primarily for air-conditioning in mining operations, in which said cooling medium is produced above ground and is introduced by way of a primary stream down through a mine-shaft where it is heated by a secondary stream performing a cooling function at a working site, after which it is returned to the surface for re-cooling, wherein, cooling equipment including an evaporator and a condenser is utilized at the working site for heat transfer from the primary stream to the secondary stream, and wherein said secondary stream, after it has performed its cooling function at the working site, but before flowing to the cooling equipment at the working site, is subdivided into a first part-stream and a second part-stream, and wherein said first part-stream takes up heat from the condenser and then, in interchange with the primary stream is sluiced into a high-pressure system and conveyed to I above-ground, and further wherein said second part-stream S' 20 is cooled in the evaporator and then, in conjunction with t, the cooling medium of the primary stream issuing from the high-pressure system at a reduced pressure, it is pumped to I ,t equipment performing the cooling function at the working site. 4 i

2. A method as claimed in Claim 1, wherein the secondary stream is subdivided into part-streams in a ratio of 60:40, and wherein the first part-stream is heated from 21 0 C to approximately 35 0 C, while the second part-stream is cooled from 21 0 C to 3 0 C.

3. A method as claimed in Claim 1 or 2, wherein the first part-stream leaving the cooling equipment at the working site flows, by means of existing hydrostatic pressure of the high-pressure system of the primary stream and a back-up pump, to above-ground cooling equipment, and stalllenno/keop18518.92_1 4.7 I is cooled to 2.5 0 C and then reused with the primary stream forerun in the high-pressure system.

4. A refrigeration installation with cooling equipment components underground and above-ground which are linked together by way of a primary stream, wherein in the above-ground primary stream there is a wet-air preliminary cooler and cooling equipment and additionally, in a secondary stream underground, cooling equipment and pressure-change device are utilized wherein a pressure- change unit is configured as a three-chamber tube charger unit which is designed for interchange of a first part- stream of the secondary stream with the primary stream and for forwarding it to above-ground, and wherein condensers of the underground cooling equipment have the first p.k6'rt- stream flowing through them, while a second part-stream of the secondary stream flows through -6e evaporators.

The refrigeration installation according to Claim 4, wherein a pump is installed downstream of the three- chamber tube charger to compensate for frictional losses i'n 20 the underground cooling equipment and it is built into the 1 mine-shaft return pipeline.

6. The refrigeration installation according to Claim i 4, wherein, in the secondary stream, a volume divider is installed which is designed to subdivide said secondary stream in a ratio of 60

7. The refrigeration installation according to Claim 4, wherein a volume divider is designed to be adjustable.

8. The refrigeration installation according to Claim 4, wherein the underground cooling equipment is equipped with low-pressure condensers. stIlvenne/keop8518.921 3.7 t) U 1 Ie IU: 4 1; I*8 'I: 44 8 I 1.41 -I *1 16

9. The refrigeration installation according to Claim 4, wherein two cooling installations are coupled together in series underground, wherein said installations achieve a heating of the first-part stream from 21 0 C to 28.3 0 C and then to 34.90C, and a cooling of the second part-stream from 21 0 C to 11.3 0 C and then to 3 0 C. DATED THIS 6TH JULY OF 1995 SIEMAG TRANSPLAN GMBH By Its Patent Attorneys: GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia 0 *o o 0 0 004 0 i* I* S ft.. 4 f t* 0 09 ft ft.,. stafflennelkeepl8518.92 1 6.7 I I l i ABSTRACT For supplying underground workings with the cooling required for the various air-conditioning technology measures, use is made of a method and an installation in which a primary stream is appropriately cooled above-ground and then conveyed underground through the mine-shaft. Cooling equipment is installed underground by way of which, with the aid of the primary stream, a secondary stream, which has been provided by the cooling aggregates at the working sites, is cooled again. Under these conditions there is an interchange of the primary stream with a part-stream of the hot secondary stream with the aid 10 of a three-chamber tube charger, and cooling of a second part-stream of the hot secondary stream with the use of the underground cooling equipment. Because 4 0 of this there is an associated reduction of the volume of cooling medium and a diminution of the load on the entire system. Owing to the increased return-flow temperature, the above-ground cooling installation can be better exploited and the operating costs correspondingly reduced. The underground cooling equipment operates with normal condensers, so that very substantial savings in investment outlay and the cost of energy may be achieved here. 1 9I: Fig. 1 is supplied for publication. -I-