GB2045361A - Extracting energy from expansible fluids - Google Patents

Abstract

The latent energy in expansible fluids is converted to mechanical or electrical energy or the like by the utilization of a multiplicity of expanders 10, 12 wherein succeeding expanders derive energy from fluid emanating from a preceding expander from which energy was previously derived; and wherein, the mechanical outputs 11, 13 of the expanders are connected by differential energy distributing means, 40, e.g. mechanical differential gears, a hydrostatic transmission, or electric generators, so as to compensate for changes in the relative capacities of the two expanders by reason of changes in conditions in such manner that the relative change of capacities are compensated by relative changes in the speed of the mechanical output of the expanders. <IMAGE>

Description

SPECIFICATION Method and apparatus for extracting energy from expansible fluids This invention relates generally to a method and apparatus for extracting energy from fluids which are expansible, such as steam, hot brines, and the like. More particularly, the invention is directed to a method and apparatus by which the fluid is passed, successively, through successive expanders in such manner that one expander removes a portion of the latent energy of the fluid and the next expander removes a successive portion of the energy so as to achieve full utilization of the energy available.

In the present atmosphere of world-wide concern over energy, it has become increasingly important to maximize the use of energy and, particularly, to provide effective means for utilizing such energy as the energy available in hot fluids (such as hot brines beneath the surface of the earth) and steam systems and the like. I have been studying and working in this field for some period of time and have been disturbed by the present inability to achieve maximum utilization of the latent energy in such fluids as hot brines and the like as well as being concerned with the inability in such systems as exist to provide for maximum bursts of power as may be required because of unusual load conditions.

The function of feeding steam or hot brines of the like into expanders which convert the latent energy therein into mechanical or electrical energy is well known. It is also known that, under proper circumstances, steam or the like can be utilized in a primary expander and the exhaust can be utilized in a secondary expander, and so on. In such systems as exist, however, problems of balancing of loads with input and output due to fluctuations between successive expanders have besn severe.

Additionally, there is always the problem of the utilization of the full maximum surges of energy available at times of peak load requirement or the like.

It is also inherent in such systems that the multiple expanders are connected to a common shaft in such manner that there is only one fixed condition of input and load during which the successive expanders work most efficiently.

Naturally, I recognize that there have been double and triple expanders and the like in the past It has been well known in some railroad applications and other applications to provide two or more expansion zones coupled and ducted in such manner that after expansion in one expander the fluid is again additionally expanded in the next expander. In the past, all of these expanders have had a common fault in that they are so arranged and so coupled that they were designed to operate at one point of volume and pressure of input, and one point of output load. Otherwise, efficiency is not obtained.When the input or output is altered from the one optimum position, a condition will be found to exist which finds the two expanders working at different output torque and/or speed such that with their common output and fixed input relationship the two or more expanders may be "fighting" each other to a certain extent.

My invention is aimed at providing a method and apparatus for utilizing an expansible fluid for the extraction of latent energy therefrom and conversion into mechanical or electrical energy or the like wherein multiple stages of expansion of said fluid are utilized and in which the output from the expanders is differentially coupled.

The present invention therefore provides a method for utilizing the latent energy of an expansible fluid, including the steps introducing an expansible fluid in its primary condition into a first expander, removing the fluid from the said first expander after expansion therein, introducing the fluid so removed from the first expander into a second expander, removing the fluid from the said secondary expander after further expansion therein, coupling the output of each of said expanders together in a differential manner, and utilizing the combined output through the differential coupling for power purposes.

The present invention further provides apparatus for utilizing the latent energy of an expansible fluid, including a source of expansible fluid, a primary expander suitable to utilize the expansible fluids, means to introduce said expansible fluids into said primary expander, means to remove expanded fluids from said primary expander, a secondary expander, means to introduce said expanded fluid from primary expander into said secondary expander, means to remove the fluid from said secondary expander, means to transmit power from said primary and secondary expander, differential coupling means connected to the power transmitting means and means to derive mechanical power from said differential coupling means.

In this method conditions can change as will become apparent upon studying the following description of the preferred embodiment, such that even though there may be variations in the output load or input pressures and volumes, that none-the-less all of the expanders will be working so as to extract energy from all of them which energy is combined through the use of the unique connections utilized so as to work together regardless of these differentials and not be dependent upon one optimum condition. Thus, the expanders in my method will each run at whatever speed is necessary so as to use the available steam or other fluid in the expansion ratio necessary to utilize the maximum energy from such fluids.

The method of this invention overcomes the difficulty inherent in compounded engines in the past, nameiy the inability of the two expanders to adjust their relative capacities so as to accommodate the varying load requirements.

The foregoing and other features and advantages will be clear to those skilled in the art upon reading the following description of preferred embodiments of the invention together with the accompanying drawings wherein: FIGURE 1 is a schematic block diagram of a preferred apparatus for practicing the method of this invention; FIGURE 2 is a schematic diagram illustrating valving which may be used in the embodiment of FIGURE 1; FIGURE 3 is a schematic, partially sectioned, view of a differential mechanism to balance the output of the two expanders of FIGURE 1; FiGURE 4 is a schematic block diagram of an alternate means to balance the output of the two expanders of FIGURE 1; and, FIGURE 5 is a schematic block diagram of another alternate means to balance the output of the two expanders of FIGURE 1.

FIGURE 1 discloses a block schematic diagram of a preferred embodiment of an apparatus to practice the method of this invention. A source of fluid containing latent energy is indicated at the block 30 and is shown to be connected through piping 18, through control valve 17, through shutoff valve 26, in piping 14, into the intake of an expander 10. Expander 10 will be referred to as the primary expander. It will further be noted that the exhaust 1 5 from the primary expander 10 enters a valve 23 from which it may be interconnected either to the intake 24 of secondary expander 12 or may bt: interconnected to the exhaust 27 from the secondary expander 12.

Likewise, it will be noted that through the teeconnection 16, the primary fluid source may be interconnected through valve 19 direct to the intake 24 through the piping 20.

It will be noted that the exhaust through piping 25 and/or piping 27 through valve 126 and interconnecting piping 28 may pass to a condenser or the like 31 which will then be interconnected by piping 29 to the primary source 30 which might be a boiler or the like. It should be understood that 31 might also merely illustrate ultimate disposition such as return through a conduit to a brine source beneath the surface of the earth or the like. Also the primary source 30 may be such a source as hot brine beneath the surface of the earth.

The primary expander 10 has an output illustrated by an output shaft 11 and the secondary expander 12 has an output illustrated by the output shaft 13. The outputs are interconnected at 40 by means which will be further illustrated in FIGURES 3 4, and 5 so as to balance the load between them. It will be particularly noted that in the illustration of FIGURE 1 the secondary expander 12 is shown to be larger in size than the primary expander 10. It is understood that such a condition normally will exist due to the expansion of the fluid through primary expander 10 causing a larger volume of fluid to be available to secondary expander 12. It should be further understood that while two expanders have been shown it is recognized that additional expanders could be utilized in a like manner and it is not intended to limit this method to two expanders.

FIGURE 2 illustrates schematically the position of the valving shown in FIGURE 1, and in particular shows the interrelationship of the three valves 19, 23 and 26. Valve 26 is controlled by a solenoid 26a activated by a switch 34 and utilizing a power source 33, by means which are well known to those skilled in the art. Similarly valves 1 9 and 23 are activated by their respective solenoids 1 9a and 23a and operate through a single switch 32 which can be powered by the same power source 33. It is evident to those skilled in the art that the valves 19, 23 and 26 need not be solenoid valves but could be hydraulically operated valves, or even manually operated valves. It is to be particularly noted however that each valve has two positions, one shown by the solid lines in the FIGURE 2 illustration and the other alternate position shown by the dotted lines.It is to be observed that valve 26 may operate independently but valves 19 and 23 will act together. Thus when the valve 19 closes the line 20 as is illustrated, the valve 23 will have closed the line 25 and when the valve 19 has opened the line 20, the valve 23 will have opened the line 25 and closed the line 22.

It is quite clear that during operation, then, both expanders 10, 20 may, if desired, receive the direct live fluid from the primary source of fluid, or either expander 10, 20 may receive the same independently, or the first expander 10 may receive the same and pass it on to the second expander 20 for further utilization of remaining latent energy.

A control valve 1 7 is illustrated which control valve 17 can control the overall amount of fluid entering the system.

FIGURE 3 illustrates one arrangement which might be placed within the output block 40 of FIGURE 1. It is noted that the input shafts 11 and 13 from the primary and secondary expanders 10, 20 respectively are shown. Shafts 11 and 13 are connected to gears 41 and 42 respectively which in turn mesh with gears 43 and 44.

The gear 43 it will be noted is journalled upon shaft 45. Shaft 45 also has journalled thereon sun gear 51 which is fastened with appropriate pins or the like 52 to gear 43. Planet gears 48 and 49 are enmeshed with sun gear 51 and are carried by carrier plate 47 which is fixed to shaft 45.

Planet gears 48 and 49 are enmeshed at point 50 with internal teeth on the gear 50a. The shaft 45 is shown to be journalled merely for pilot position at reduced area 53 in the end of shaft 46.

A pair of holes 56 has been provided through the gear 50a and a pair of holes 57 matching are provided in the carrier plate as indicated. The pins 55 carried by collar 54 which is slidably mounted on shaft 46 are capable of being inserted through holes 56 and into holes 57 so as to lock this differential mechanism in one position as desired.

The collar 54 would normally be actuated by a yoke (not shown) or the like as is known in the art.

Gear 40 is fixed to shaft 46 as is gear 58. The gear 58 meshes with gear 43 and provides output to shaft 59 as indicated.

By the mechanism as shown in FIGURE 3 the load between the expanders 10, 20 may be balanced, or the two may be locked together as desired by the yoke and pin arrangement as previously described. The differential motion and the balancing of the load will be clear to those skilled in the art through the gearing as indicated.

FIGURE 4 shows another method of distributing the load between the two expanders 10, 20 so that they do not work against one another and do work in unison. In this case it is noted that shaft 11 and 13 respectively are connected to generators 60 and 61. The generators SO and 61 each have fields of 62 and 63 respectively and armatures 64 and 65 respectively as is known in the art. The fields 62 and 63 however, are separately excited, as by batteries or the like 67 and 66, and thus the differences, if any, between the generation of current is balanced and is taken out as load current at 68.

It will be seen, therefore, that the mechanical output shafts 11, 13 of the compounded expanders 10, 20 in FIGURE 4 are drivingly connected to the independently rotatable armatures 64,65 of the generators 60,61, which generators are electrically connected in parallel with the combined electrical outpuT 68 connected to a common electrical load. The field current of the generators 64, 65 is independent of the load current, so that an increase in the rotational speed of one armature 64,65 will cause proportionate increase in the voltage output of that armature, causing an increase in current flowing through the two armatures 64, 65 in the common load and a resultant increase in the torque demand of the other armature.

FIGURE 5 shows another way of balancing the load wherein the input shaft 11 and 1 3 are connected to hydraulic pumps 70 and 71. The pumps exhaust fluids pass through lines 74 and 75 which are jointly fed into line 76. being the intake of hydraulic motor 80. Check valves 78 and 77 are provided ss indicated so as to avoid any back pressure in the event one of the units should fail, or the like. Return from the hydraulic motor passes through line 79 and is divided through line 72 and 73 into the two pumps. The shaft 81 of the hydraulic motor provides the ultimate load.

With the arrangement in FIGURE 5 the output shafts 11, 1 3 of the compounded expanders 10, 20 are individually connected to individual hydraulic pumps 70, 71 with each of the pumps 70, 71 discharging into the manifold supply line 76 connected to the input of the hydraulic motor 81. The hydraulic motor 81 becomes the common load of the compounded expanders 10, 20 and its outlet is ducted to the intakes 72, 73 of the hydraulic pumps 70,71. An increase in the speed of one of the compounded expanders 10, 20 will increase the output of its pump, thereby increasing the hydro-static pressure in the hydraulic motor supply line and increasing the torque demand on the other expander causing a reduction in speed.If the expander which has been slowed is the primary expander 10, it will meter less fluid into the duct connecting its outlet with the intake of the secondary expander, thereby slowing the secondary expander 20 by reason of the decreased pressure in the duct connecting the inlet of the secondary expander 20 to the exhaust of the primary expander 10. The decrease in pressure in the connecting duct will reduce the torque output of the secondary expander 20 and increase the torque of the primary expander 10 until the two torques are in balance.

It will be clear to those skilled in the art, that differentials in the input load of shafts 11 and 13 will therefore be compensated for through this hydraulic arrangement and the ultimate load will properly be the combined output of the two expanders.

While the embodiments of this invention shown and described are fully capable of achieving the objects and advantages desired, it should be clear that these embodiments have been shown for purposes of illustration only, and not for purposes of limitation.

Claims (14)

1. A method for utilizing the latent energy of an expansible fluid, including the steps of introducing an expansible fluid in its primary condition into a first expander, removing the fluid from the said first expander aster expansion therein, intrnducing the fluid so removed from the first expander into a second expander, removing the fluid from the said secondary expander after further expansion therein, coupling the output of each of said expanders together in a differential manner, and utilizing the combined output through the differential coupling for power purposes.

2. The method of Claim 1 wherein the expansible fluid is steam and wherein the exhaust from the secondary expander is carried to a condenser thence back to a steam generator for recycling.

3. The method of Claim 1 or 2 wherein the expansible fluid in its primary condition is alternately introduced into the second expander and during such time the fluid removed from the first expander is diverted from the second expander.

4. The method of Claim 1, 2 or 3 wherein the ratio of torque output of said expanders is varied by means of a differential coupling.

5. A method of coupling two or more expanders to an external load in such a manner that the torque delivered by the first expander bears a constant ratio to the individual torques delivered by successive expanders, said method including the steps of connecting a source of expansible fluid to the intake of a first expander, connecting the exhaust of said first expander to the intake of a second, and larger expander, connecting the exhaust of the second expander to a disposition zone, connecting the power output of the first expander to one element of a differential means, connecting the power output of the second expander to a second element of said differential means, and connecting a third element of said differential means to a load.

6. The method of Claim 5 in which the exhaust of said second expander is connected to the intake of a third expander.

7. Apparatus for utilizing the latent energy of an expansible fluid, including a source of expansible fluid, a primary expander suitable to utilize the expansible fluids, means to introduce said expansible fluids into said primary expander, means to remove expanded fluids from said primary expander, a secondary expander, means to introduce said expanded fluid from primary expander into said secondary expander, means to remove the fluid from soid secondary expander, means to transmit power from said primary and secondary expander, differential coupling means connected to the power transmitting means, and means to derive mechanical power from said differential coupling means.

8. The apparatus of Claim 7 in which the said differential coupling means comprises a mechanically geared differential device.

9. The apparatus of Claim 7 wherein the differential coupling means includes two hydraulic pumps and in which said two hydraulic pumps jointly activate a single hydraulic motor.

10. The apparatus of Claim 7 wherein the differential coupling means comprises two electrical generators so connected as to generate electricity and transmit the same through a common transmission line.

11. The apparatus of Claim 10 wherein independent means are provided to excite the fields of the two generators.

1 2. The method for utilizing the latent energy of an expansible fluid, substantially as herein described.

13. The method for coup!ing two or more expanders to an external load substantially as herein described with reference to Figures 1 and 2 or Figure 3 or Figure 4 or Figure 5 of the accompanying drawings.

14. The apparatus for utilizing the latent energy of an expansible fluid constructed substantially as herein described with reference to Figures 1 and 2 or Figure 3 or Figure 4 or Figure 5 of the accompanying drawings.