GB2270119A - Thermodynamic apparatus. - Google Patents

Abstract

Thermodynamic apparatus 12 of cylindrical shape has a boiler 14 at one end to provide vapour at high pressure and temperature, and a condenser 16 at an opposed end to condense spent vapour. A rotor 30, rotatable about axis 34, has concentric annular partitions 42 forming annular chambers 44. Longitudinal and radial partitions (46, Fig 4) divide the annular chambers into sub-chambers (48), which have open radial extremities to form condensate ports. A drum 50 around the rotor freely rotates in sympathy with the rotor about axis 52 parallel to and spaced from axis 34 and supports a condensate jacket 66. Due to eccentricity, condensate cyclically moves into and out of sub-chambers respectively to contract and expand each sub-chamber. Valve means directs vapour into sub-chambers of the first annular chamber while they expand. The vapour expands against and pressure. When a sub-chamber contracts, the valve the condensate to do useful work while transferring heat means conducts vapour therefrom to a diametrically opposed expanding sub-chamber of a subsequent annular chamber. Vapour passes from the boiler to the condenser and condensate passes from the condenser to the boiler via the annular chambers. <IMAGE>

Description

THERMODYNAMIC APPARATUS THIS INVENTION relates to thermodynamic apparatus suitable for use in performing a thermodynamic cycle or quasi cycle.

The Applicant envisages that an important application of this invention will be the expansion of high pressure steam in an electrical power station.

For convenience, for purposes of this specification, the above application, and using water as a thermodynamic fluid, will primarily be borne in mind. The invention is, however, neither limited to expansion of high pressure steam for use in an electrical power station, nor to the use of water as a thermodynamic working fluid.

In accordance with the invention, broadly, there is provided thermodynamic apparatus, suitable for use in a thermodynamic cycle or quasi cycle, into which apparatus high pressure, high temperature vapour is introduced and is allowed to expand to do useful work, the apparatus having vapour inlet means adapted for operative connection to a boiler, condensate inlet means adapted for operative connection to a condenser, vapour outlet means adapted for operative connection to the condenser, and condensate outlet means adapted for operative connection to the boiler, the apparatus being adapted, in use, to provide a vapour/condensate interface which is substantially at saturation point, and which has a thermodynamic gradient in respect of pressure and temperature ranging substantially from the condition at the vapour inlet to the condition at the condensate inlet, the vapour being allowed to migrate in use from the vapour inlet to the vapour outlet while following said thermodynamic gradient, the vapour continually expanding against said vapour/condensate interface to do useful work, the condensate being allowed to migrate from the condensate inlet to the condensate outlet while following said thermodynamic gradient, heat transfer from the vapour to the condensate continually taking place across said interface.

The boiler provides a source of high pressure, high temperature vapour and a sink for high pressure, high temperature condensate. Accordingly, the condenser provides a source of low pressure, low temperature condensate and a sink for low pressure, low temperature vapour. In one kind of embodiment, the thermodynamic working fluid may be water, the vapour being steam and the condensate being liquid water. In other kinds of embodiments, the working fluid may be molten/evaporated metal such as mercury, carbohydrate thermodynamic fluids such as Freon, or the like.

The thermodynamic gradient may be in the form of a stepped gradient.

The apparatus may be rotary apparatus. It may, generally, be of round cylindrical form. The vapour inlet and condensate outlet may be toward one end, a boiler end of the rotary apparatus, the vapour outlet and condensate inlet then being toward an opposed end, a condenser end of the apparatus.

The gradient will then extend between the boiler end and the condenser end of the apparatus.

More specifically, the rotary apparatus of generally round cylindrical shape may comprise a rotor including a shaft rotatably supported about a rotor axis, the shaft having connecting means for driving connection to a rotary load, a plurality of annular partitions which are mounted on the shaft in axially spaced, concentric arrangement to form, between adjacent partitions, annular chambers, a plurality of sectorial partitions which are mounted on the shaft in longitudinally and substantially radially extending arrangement to divide the respective annular chambers into truncated sector shaped sub-chambers, each sub-chamber having, at a radial extremity thereof, a condensate port, and, spaced from the condensate port, a vapour port;; an outer, round cylindrical drum around the rotor and mounted for rotation about a drum axis generally alongside ie transversely spaced from, the rotor axis, the arrangement being such that the drum is allowed to rotate in sympathy with the rotor in use and such that, at a first angular station, radially outer extremities of the sub-chambers will be closely proximate, at a minimum spacing from an inner periphery of the drum, and that, at a diametrically opposed angular station, said radially outer extremities of the sub-chambers will be at a substantial or maximum spacing from the inner periphery of the drum; vapour inlet means at a first end of the rotary apparatus for connection to a source of high pressure, high temperature vapour or boiler; vapour outlet means at a second, opposed end of the rotary apparatus for connection to a condenser;; condensate inlet means at said second end for connection to the condenser; condensate outlet means at said first end for connection to the boiler; composite valve means connected to the source of high temperature, high pressure vapour, and having a valve associated with each pair of adjacent annular chambers, each valve being adapted, via the respective vapour ports, to transfer vapour from sub-chambers of one annular chamber when said sub-chambers are, successively, undergoing contraction, to sub-chambers of an adjacent annular chamber toward the second end of the apparatus when said sub-chambers of the adjacent annular chamber, successively, undergo expansion, thus allowing the vapour to migrate from the first to the second end of the apparatus in use, condensate forming, in use, under centrifugal force, a condensate jacket along the inner periphery of the outer drum, the jacket being of tapering thickness from the second end to the first end of the apparatus and of constant thickness around its periphery at any axial station, the condensate flowing freely into the respective sub-chambers via the condensate ports while rotating from the first angular station to the diametrically opposed angular station to cause expansion of the sub-chambers, the condensate flowing freely out of the respective sub-chambers via the condensate ports while rotating from the diametrically opposed angular station to the first angular station, the vapour in the sub-chambers and the condensate in the jacket and extending into the sub-chambers forming a vapour/condensate interface across which heat is transferred from the vapour to the condensate on a continual basis in use.

The invention is now described by way of example with reference to the accompanying diagrammatic drawings. In the drawings Figure 1 shows, diagrammatically, power generation in an electrical power plant which utilizes apparatus in accordance with this invention; Figure 2 shows, diagrammatically, a thermodynamic representation on a temperature / entropy plot of the thermodynamic cycle of the apparatus in accordance with the invention; Figure 3 shows, in axial section, an apparatus in accordance with the invention; Figure 4 shows, in cross-section, apparatus similar to the apparatus of Figure 3; and Figure 5 shows, diagrammatically, operation of valve means of the apparatus of Figure 4.

With reference to the drawings, and more specifically Figure 1, a power generating means in accordance with the invention for generating electrical power in an electrical power station is generally indicated by reference numerall0. The power generating means 10 comprises an apparatus 12 in accordance with the invention and which is described in more detail hereinafter. The apparatus 12 receives steam at high pressure and high temperature from a boiler 14. Thermodynamic energy in the steam is converted into mechanical energy within the apparatus 12 and is transmitted as shaft work as indicated by reference numeral 22 to a generator 18. Steam at relatively low pressure and low temperature is conducted as indicated by reference numeral 24 to a condenser 16.From the condenser 16, as indicated by reference numeral 26, condensate is introduced into the apparatus 12. Condensate at relatively high temperature and pressure is conducted as indicated by reference numeral 28 back to the boiler 14.

Within the apparatus 12, steam migrates from the high pressure high temperature steam inlet at 20 to the low pressure low temperature steam outlet at 24 while, simultaneously, condensate migrates from the low pressure low temperature inlet at 26 to the high temperature high pressure outlet at 28. In accordance with the invention, heat is transmitted on a continual basis within the apparatus 12 from the steam to the condensate.

The apparatus 12 thus allows the power generating means 10 to operate in a manner approaching a regenerative cycle as will be described with reference to Figure 2.

With reference to Figure 2, a thermodynamic representation on a temperature / entropy plot represents the method effected by means of the apparatus of Figure 1.

Condensate is evaporated in the boiler 14 from a thermodynamic state 2 to a thermodynamic state 3.

In the condenser, steam received from the apparatus 12 is condensed from a thermodynamic state 4 to a thermodynamic state 1. In accordance with the invention steam is continually expanded, in a plurality of steps, respectively, adiabatically, from a high pressure to a low pressure whereas, simultaneously, condensate is continually heated and pressurized. The internal expansion of the steam and heating and pressurizing of the water are effected in a finite number of discrete steps. The arrows represent transfer of heat at substantially constant temperature.

It is appreciated that regeneration takes place in a number of finite steps and not on a truly continuous basis.

Thus, the practical thermodynamic cycle only approaches a truly regenerative cycle.

It is further to be appreciated that a truly regenerative cycle has the same potential efficiency than a comparable Carnot cycle which represents the maximum potential efficiency which can be obtained for given temperature limits.

Thus, in accordance with the invention, Carnot efficiency is approached even though it cannot be obtained in practice.

With reference to Figures 3 and 4, an embodiment of apparatus 12 is now described. It is emphasized that the broad principles of construction and operation of such apparatus are focussed on, and not detail design. Furthermore, in the interest of clarity of drawing and ease of perception, some of the dimensional ratios have been distorted when Figure 3, Figure 4 and Figure 5 are compared. The principles of construction and operation are, however, the same.

The apparatus in accordance with the invention is generally indicated by reference numeral 12. The apparatus 12 is adjoined at one end by the boiler 14, and at an opposite end by the condenser 16. In the embodiment shown, the apparatus 12 is actually an integral apparatus of which the boiler 14 and condenser 16 form part.

The apparatus 12 comprises a rotor 30 having a central shaft 32 which is rotatably supported in bearings 33 about a rotation axis 34. The rotor further has end plates 36, 38 which are effectively mounted on the shaft 32. The end plates 36, 38 are circumferentially joined at positions inwardly spaced from their radially outer circumferences by means of an inner barrel 40. The barrel 40 is not solid and has a large number of ports which will be mentioned hereinafter.

A plurality of annular partitions 42 are fixed at their radially inner circumferences to the barrel 40 to extend outwardly, parallel with the outer portions of the end plates 36 and 38 thus to form annular chambers 44 between respective pairs of partitions.

As can best be seen in Figure 4, longitudinally and radially extending, circumferentially spaced, longitudinal partitions 46 extend between the axially outer annular partitions 42 to divide each annular chamber 44 into a plurality of sectorially shaped sub-chambers 48. At its inner periphery, each sub-chamber 48 has an open port which was mentioned above.

Furthermore, along the outer periphery, the sub-chambers are not bound and ports are formed over their whole radially outer extremities.

The apparatus 12 further comprises a drum 50 around the rotor 30. The drum 50 is mounted on bearings 54 for free rotation about an axis 52 which is offset from or eccentric to the rotor axis 34. Thus, at one point on the periphery, which is indicated by reference number 72 in Figure 4, the spacing between the outer periphery of the rotor 30 and the inner periphery of the drum 50 is relatively close and at a minimum.

At a diametrically opposed point 74, the clearance is at a maximum.

From the condenser end of the apparatus 12, an axially extending central pipe 58, conveniently on the axis 34, extends into the condenser 16. An upper portion of the central pipe 58, indicated by reference numeral 61, forms a conduit serving the condenser 16. A lower portion 62 is in the form of a tubular support. The bearings 33 supporting the shaft 32 are located within the tubular support 62.

The apparatus 12 is surrounded by means of a stationary outer casing 64.

In use, the rotor is rotated at synchronous speed, e.g.

3000 r.p.m. or 50 hz as is the standard in South Africa, or at whichever speed the apparatus is to operate. On account of friction, the drum 50 will rotate in sympathy. Steam is introduced into the apparatus 12 from the boiler 14. The mechanism of conducting the steam will be described in more detail with reference to Figure 5. However, generally, steam is introduced at a lower end of the apparatus 12 and migrates upwardly as will be explained hereinafter to be exhausted into the condenser 16.

Condensate from the condenser 16 is introduced at the uppermost part of the condensate jacket as shown at 67. Because of rotation of the drum 50 in use, and the resulting centrifugal forces, the condensate 66 forms a peripheral jacket against the periphery of the drum 50. Furthermore, because the annular cambers 44 are open along their outer peripheries, the condensate can freely flow into the annular chambers.

The steam 65 and condensate 66 form a composite interface 70 throughout the length and toward the periphery of the apparatus 12. The condensate jacket is formed on account of centrifugal forces because of rotation, and also on account of steam pressure. It is to be appreciated that, toward the boiler end of the apparatus 12, steam pressure is high and toward the condenser end of the apparatus 12, steam pressure is low. Thus, the high steam pressure displaces the interface 70 toward the boiler end radially outwardly relative to the radial position of the interface 70 toward the condenser end. Thus, the thickness of the condensate jacket tapers from the condenser end toward the boiler end as is shown in Figure 3.

It is to be appreciated that the condensate jacket is concentric to the drum 50 i.e. to the drum axis 52. On account of the eccentricity of the drum axis 52 to the rotor axis 34, and as can best be seen in Figure 4, at the angular position 72, penetration of the condensate jacket into the rotor is at a maximum and, at the angular position 74, such penetration is at a minimum. Thus, viewing one sub-chamber 48 as it rotates from the angular position 72, through the angular position 74 back to the angular position 72, initially condensate penetration is at a maximum thus rendering the effective volume of the chamber available to steam at a minimum. Such effective volume progressively increases until it is at a maximum at the angular position 74. From the position 74 to the position 72, the effective volume decreases.When a sub-chamber 48 is about at the zero degree position 72, until it reaches about the 1800 position 74 steam under pressure is progressively introduced into the effective volume of the sub-chamber 48. The sub-chamber increases in volume and the steam is thus allowed to expand against the interface 70 formed by the condensate. From about the 1800 position 74, when the effective volume of the subchamber 48 decreases, steam is let out until about the O position at 72 is reached.

For the sub-chambers 48 in the lowermost annular chamber 44, steam is obtained from the annular chamber immediately above the end plate 38. By means of the valve mechanism, as will be described hereinafter, steam from the subchambers, 48 in the lowermost annular chamber 44 is guided when being let out to (diametrically) opposed sub-chambers 48 in the succeeding annular chamber 44. When the steam is let out of the sub-chambers 48 of such succeeding annular chamber 44, the steam is guided to the sub-chambers 48 of the next succeeding annular chamber 44, and so on.

It is to be appreciated that the pressure of the steam progressively decreases as it migrates from one annular chamber to a succeeding annular chamber with expansion and heat transfer.

Thus, the pressure in the apparatus 12 decreases generally from the boiler end to the condenser end.

It is to be appreciated that, in each annular chamber 44, the pressure is substantially constant, i.e. the steam pressure and the condensate pressure (neglecting the effects of centrifugal forces) are substantially equal, and that the condensate pressure, correspondingly, increases from the condenser end to the boiler end. Furthermore, it is emphasized that condensate can freely flow downwardly along the condensate jacket and that there is a general migration of condensate from the condenser end to the boiler end.

Furthermore, energy in the form of heat is transferred from the steam to the condensate across the respective interfaces 70. Because such energy transfer takes place in a number of steps, it approaches energy transfer at constant temperature.

Thus, equalizing of pressures across the interface 70 and transfer of heat energy across the interface 70 approach the situation explained with reference to Figure 2 and render operation of the apparatus 12 regenerative to a degree. Thus, it is contended by the Applicant that the apparatus 12 will have a thermodynamic efficiency approaching the thermodynamic efficiency of a Carnot cycle. To appreciate the significance of this, it is to be borne in mind that the thermodynamic efficiency of a state of the art conventional electric power station is of the order of about 60% to 65% of Carnot efficiency. The Inventor anticipates that apparatus in accordance with his invention will operate at an efficiency of the order of about 80% of Carnot efficiency i.e. at a substantially higher efficiency than a comparable conventional power station.

With reference to Figure 5, in which operation of the valve mechanism is schematically shown, an annular chamber 44.0 immediately above the end plate 38 (not shown in Figure 5) and the lowermost annular partition 42.1, is not sectorially sub divided and is communicated with an outlet of the boiler t receive steam at maximum pressure and temperature. While any one sub-chamber 48 of the annular chamber 44.1 is rotated from about the angular position 72 to about the angular position 74, i.e.

while the effective volume of the chamber increases, steam is allowed to flow as shown at 45.0 from the chamber 44.0 into the sub-chamber 48 of the annular chamber 44.1. The steam expands against the interface 70.1 thus doing mechanical work. Also, heat is transferred across the interface 70.1 to the condensate.

While the sub-chamber rotates from the angular position 74 to the angular position 72, i.e. while its effective volume contracts or decreases, the valve mechanism intercommunicates it with an associated sub-chamber 48, e.g. a diametrically opposed subchamber 48, in the succeeding annular chamber 44.2, to allow steam to flow as indicated at 45.1. These steps are cyclically effected, successively, for all the sub-chambers 48 in all of the annular chambers 44.

It is to be appreciated that the above steps take place at high speed and provision is made for time lags. Thus, the "open" period or dwell angle is not necessarily 1800, and intercommunication is not necessarily diametrically opposed.

However, the principle remains.

The Applicant believes that this invention will improve the efficiency of practical thermodynamic cycles in general and can find wide application, e.g. by converting waste heat in a conventional Otto or Diesel, or like engine into mechanical power. In the generation of electrical power in power stations, even a nominally small increase in efficiency will have far reaching beneficial effects.

It is emphasized that the invention can find application with a variety of thermodynamic working fluids.

Claims (9)

CLAIMS:

1. Thermodynamic apparatus, suitable for use in a thermodynamic cycle or quasi cycle, into which apparatus high pressure, high temperature vapour is introduced and is allowed to expand to do useful work, the apparatus having vappur inlet means adapted for operative connection to a boiler, condensate inlet means adapted for operative connection to a condenser, vapour outlet means adapted for operative connection to the condenser, and condensate outlet means adapted for operative connection to the boiler, the apparatus being adapted, in use, to provide a vapour/condensate interface which is substantially at saturation point, and which has a thermodynamic gradient in respect of pressure and temperature ranging substantially from the condition at the vapour inlet to the condition at the condensate inlet, the vapour being allowed to migrate in use from the vapour inlet to the vapour outlet while following said thermodynamic gradient, the vapour continually expanding against said vapour/condensate interface to do useful work, the condensate being allowed to migrate from the condensate inlet to the condensate outlet while following said thermodynamic gradient, heat transfer from the vapour to the condensate continually taking place across said interface.

2. Thermodynamic apparatus as claimed in Claim 1 in which the thermodynamic working fluid is water, the vapour being steam and the condensate being liquid water.

3. Thermodynamic apparatus as claimed in Claim 1 in which the thermodynamic working fluid is selected from molten/evaporated metal, and a carbohydrate thermodynamic fluid.

4. Thermodynamic apparatus as claimed in any one of the preceding claims in which the thermodynamic gradient is in the form of a stepped gradient.

5. Thermodynamic apparatus as claimed in any one of the preceding claims in which the apparatus is a rotary apparatus of round cylindrical form.

6. Thermodynamic apparatus as claimed in Claim 5 in which the vapour inlet and condensate outlet are toward one end, a boiler end of the rotary apparatus, the vapour outlet and condensate inlet then being toward an opposed end, a condenser end of the apparatus.

7. Thermodynamic apparatus as claimed in Claim 6 insofar as it is dependant from Claim 4, in which the gradient extends between the boiler end and the condenser end of the apparatus.

8. Thermodynamic apparatus as claimed in Claim 5, Claim 6, or Claim 7 in which the rotary apparatus of generally round cylindrical shape comprises a rotor including a shaft rotatably supported about a rotor axis, the shaft having connecting means for driving connection to a rotary load, a plurality of annular partitions which are mounted on the shaft in axially spaced, concentric arrangement to form, between adjacent partitions, annular chambers, a plurality of sectorial partitions which are mounted on the shaft in longitudinally and substantially radially extending arrangement to divide the respective annular chambers into truncated sector shaped sub-chambers, each sub-chamber having, at a radial extremity thereof, a condensate port, and, spaced from the condensate port, a vapour port;; an outer, round cylindrical drum around the rotor and mounted for rotation about a drum axis generally alongside ie transversely spaced from, the rotor axis, the arrangement being such that the drum is allowed to rotate in sympathy with the rotor in use and such that, at a first angular station, radially outer extremities of the sub-chambers will be closely proximate, at a minimum spacing from an inner periphery of the drum, and that, at a diametrically opposed angular station, said radially outer extremities of the sub-chambers will be at a substantial or maximum spacing from the inner periphery of the drum; vapour inlet means at a first end of the rotary apparatus for connection to a source of high pressure, high temperature vapour or boiler; vapour outlet means at a second, opposed end of the rotary apparatus for connection to a condenser;; condensate inlet means at said second end for connection to the condenser; condensate outlet means at said first end for connection to the boiler; composite valve means connected to the source of high temperature, high pressure vapour, and having a valve associated with each pair of adjacent annular chambers, each valve being adapted, via the respective vapour ports, to transfer vapour from sub-chambers of one annular chamber when said sub-chambers are, successively, undergoing contraction, to sub-chambers of an adjacent annular chamber toward the second end of the apparatus when said sub-chambers of the adjacent annular chamber, successively, undergo expansion, thus allowing the vapour to migrate from the first to the second end of the apparatus in use, condensate forming, in use, under centrifugal force, a condensate jacket along the inner periphery of the outer drum, the jacket being of tapering thickness from the second end to the first end of the apparatus and of constant thickness around its periphery at any axial station, the condensate flowing freely into the respective sub-chambers via the condensate ports while rotating from the first angular station to the diametrically opposed angular station to cause expansion of the sub-chambers, the condensate flowing freely out of the respective sub-chambers via the condensate ports while rotating from the diametrically opposed angular station to the first angular station, the vapour in the sub-chambers and the condensate in the jacket-and extending into the sub-chambers forming a vapourlcondensate interface across which heat is transferred from the vapour to the condensate on a continual basis in use.

9. Thermodynamic apparatus substantially as described herein with reference to the accompanying drawings.