US2907169A - Hot fluid engine with movable regenerator - Google Patents

Description

Oct. 6, 1959 p A. B. NEWTON HOT FLUID ENGINE WITH MOVABLE REGENERATOR 3 Sheets-Sheet 1 Filed Dec.

v INVENTOR" mfiVZa/M ATTORNEYS.

Oct. 6, 1959 A. B. NEWTON 2,907,169

' HOT FLUID ENGINE WITH MOVABLE REGENERATOR Filed Dec. 10, 1957 3 Sheets-Sheet 2 ATTORNEYS.

Oct. 6, 1959 A. B. NEWTON 2,

HOT FLUID ENGINE WITH MOVABLE REGENERATOR Filed Dec. 10, 1957 3 Sheets-Sheet ,3

I? k 2 HEAT RETURN FROM REGENERATOR a m m 20 a HEAT STORAGE IN REGENERATOR ENTOR- Qam m BY PISTON TRAEL ATTORNEY United States Patent H I 2,907,169 nor FLUID'ENGlNli, WITH MOVABLE REGENERATOR Alwin B. Newton,.Wichita, Kans. Application December 10, 1957, Serial No. 701,812

14 Claims. (Cl.60 24)1 This invention relates to a hot fluidengine with movable regenerator, and is particularly useful in connection with a uni-flow type hot gas or vapor engine.

This application is a continuation-in-part of my copending application Serial No. 439,205, filed June 25, 1954, now abandoned.

An object of the invention is to provide in a hot fluid engine a movable regenerator and connecting means whereby the regenerator may be moved back and forth through the gas or other fluid in order to change the physical size of the hot and cold gas or' fluid spaces. Another object is to provide insuch a structure an arrangement in which the regeneratoris moved in phase with the. pistons. Yet another objectis to provide a hot fluid engine in which the working fluid orvapor may be partially condensed as it moves into the cold end of the chamber against a cold regenerator and re-evaporated as it is drawn back into the hot end of the engine. Still another object is to provide a hot fluid engine with movable regenerator in which the regenerator is moved out of phase with the piston. A still further object is to provide a hot fluid engine piston and regenerator structure of novel combination in which high efficiency is obtained either in single or multiple piston units. Other specific objects and advantages will appear as the specification proceeds. v

The invention is shown, in an illustrative embodiment, by the accompanying drawing, in which Figure 1 is a vertical sectional view of an engine embodying my invention; Fig. 2, a transverse detail sectional view, the section being taken as indicated at line 22 of Fig. 1; Fig. 3, a broken, partly sectional, view of a modified form of structure embodying my invention; Fig. 4, a broken, part sectional, view of a structure showing a further modification of my invention; and Fig. 5, a graph setting out a pressure diagram.

In the illustration given, a crankshaft is shown journaled within bearings provided by a casing 11. The two crank arms 12 and 13 extend from the crankshaft 10 to pistons 14 and 15, respectively. Piston 14 is mounted within a cylinder 16, and piston 15 is mounted within a cylinder 17. The cylinders are provided with longitudinal slots 18 adapted to receive drive pins 19 which are fixed to the pistons 14 and 15. The pins 19 extend laterally of the cylinders 16 and 17 for a purpose which will be later indicated.

About the cylinder 16 and spaced therefrom, I provide a casing 20forming, between the cylinder and the casing, a pressure chamber 21. Similarly, I provide about the cylinder v17 a casing 22 which provides a pressure chamber 23. Each of the chambers 21 and 23 is provided near its lower side with cooling fins 24, as shown more clearly in Fig. 1. I

Any suitable means for heating the upper or outer ends of the casing members 20 and 22 may be provided. In the illustration given, I provide the outer arcuate end portions 25 of the casing members 20 and 22 with fins 26,

and about such end portions I provide a bonnet or enclosure 27. Within the enclosure 27 extends a burner 28, which may be employed for heating the interior of the bonnet or jacket 27. It will be understood that the heating means may be a fuel-burning means or any other type of device for supplying heat to the upper end portions 25 of the casing members 20 and 22.

The specific structure which has been described above is set forth merely as illustrative of a reversible hot gas or vapor engine. It will be understood that one or more pistons'may be employed and that the cylinders thereof may be surrounded by any type of pressure-retaining enclosures, means being provided for heating one end of the enclosures and cooling the other end.

The fluid employed may be hot air, gaseous refrigerant, or a condensing refrigerant. It will be understood that any suitable type of gas or fluid may be employed.

In the hot fluid engine, I propose to employ a movable regenerator which, in the illustration given, is indicated by the numeral 29. The regenerator may be of any suitable material such as coiled Wire, screen, a ball or mat formed of wire, or any other suitable material which is effective in storing heat and giving up heat while at the same time permitting fluid to pass therethrough. In the specific illustration given, the'regenerator consists of Wire network in the shape of a ring and secured to the ends of the pin or cross rod 19. With this structure, theregenerator is moved longitudinallyof the casing enclosing the cyl inder in phase with the piston. I While connections may be provided for causing the regenerator 29 to move out of phase with vthe piston, for the purpose of the present application I have shown the regenerator supported for movement in unison with the piston.

In the operation of the engine, the piston 14 and regenerator 29. are shownat the top of their stroke wherein the cold space has its maximum and the hot space its minimum volume, and as they move downward, the'regenerator moves through the gas or vapor in chamber 21. The relatively cold gas in the lower portionof the cylinder is thus heated, increasing the effective pressure to drive the piston and consequently the crankshaft 10. The piston 15 and its regenerator are shown at the bottom of the stroke wherein the cold space is at a minimum volume. As the piston moves up, the volume is reduced and the fluid heated by being forced out of the cylinder is now cooled by the refrigerator, which in turn becomes heated, following the cycle described above. The change in temperature and pressure may be so chosen that the working fluid will be partially condensed as it moves into the cold end against a cold regenerator and 'reevaporated as it is drawn back into the hot end of the engine; or,'if desired, a non-condensable gas may be employed as the motive fluid. The mass of the regenerator is of a proper selection so that the gas left in the cold end at the top of the piston stroke will be relatively cool throughout its mass and so that at the same time enough heat energy is stored in the regenerator to heat this mass of air as it flows back through the regenerator and past the hot end of the casing chamber into the piston chamber. The working fluid employed, the pressure and temperature level used, and the displacement of the moving piston together determine the proper mass and characteristics of the regenerator.

I prefer to maintain the pressure in the system above atmospheric and the pressure may be introduced to meet power output requirements of the engine. In Fig. 1, a: pipe 30 is shown by which a' pressure fluid may be introduced from a source (not shown), The engine itself may be used to drive such source if desired. 7 The piston 14 is preferably provided with'a skirt 14* covering the slot 18 whenthe piston is in raised position.

By'locatin'g the means for heating the gas (fluid) between the piston and the regenerator, I am able to dispense with a transfer piston or displacement member. Further, in the structure shown, the piston itself is effective in. providing the charge past'the hot zone. The structure provides means for varying the relative sizes of the hot and'cold spaces byvarying the piston relative to the heated area and the piston of the regenerator to the, heated area.

If desired, the crankshaft 10, which in itself serves as an inertia member for continuing the movement or returning the piston, may be provided with a flywheel 31. The wheel 31 may be provided with a handle 32 for manual starting of the device, and a counterweight 33' isprovided to counterbalance the weight on the handle. The take-off power shaft may lead to any mechanism which is-to be operated. For effectively sealing the casing 11, a gas-tight seal 34 may be provided about the take-off shaft 35, and it will be understood that any suitable sealingmeans may be employed.

As heretofore stated, I prefer to maintain the crankshaft chamber under pressures which may extend from atmospheric to 1000 lbs. pressure or higher, and it will be understood that suitable casing materials and sealing means Will be employed for sustaining such pressures.

While, in the drawing, I have shown a pair of cylinders connected by a crankshaft, it will be understood that a single piston may be employed with its connections, as shown, to the crankshaft 10. Further, while I have shown fins 24 for cooling the lower portion of the cylinder casing, it will be understood that this area may be cooled by the circulation of liquid thereabout or by any other suitable cooling means.

In the operation of the structure shown, heat is appliedthrough the burner 28 while at the same time cooling is effected in the lower fin-equipped portion 24 of the cylinder. At the beginning, movement may be initiated manually by turning the flywheel 31 or by any other means, and the operation then proceeds as follows:

Referring to the cylinder and piston shown on the left-hand side of Fig. 1, it will be noted that the position of the regenerator 29 is such that the volume of the cold portion of the annular space 23 is at a minimum. Also, the volume within the annular space and the cylinder 17 combined is at a maximum. The regenerator has been cooled to its lowest temperature by its previous passage through the gases in the annular space andby the passage of the gases from that space into the cylinder 17 through the regenerator. The largest percentage of the gas occupying chambers 23 and cylinder 17 is at a relatively hot temperature. The combined effect of the increased volume of the chambers and the higher temperatures of a relatively large portion of the gas is such that the pressure within the chamber, as determined by the well-known equation PV=RT, is at a minimum.

The continued rotation of the crankshaft 10 as caused by its own inertia or by the flywheel 31 or a companion piston, is to move the piston and regenerator 29.up-. wards in their respective enclosures. Since the regenerator 29 is formed of a coil of wire, the gases flow readily through it as the piston moves upwardly and reduces the volume within the chambers constituted by the cylinder and annular space 23, the upward movement of the piston tending to increase the pressure in such space. However, regenerator 29, which is now cold, immediately passes through some of the heated gas in the annular space23 which resided above the regenerator. as. piston 15 compresses the gas within the chambers, some flow occurs through the regenerator as the pressure in the. cold end of the annular space below the regenerator is; increased. The heat capacity of the regenerator is; such that it receives heat within the space of a verysmall motion of the piston and regenerator, thus lowering the temperature of a sufficient relative volume f-t e. gas the spaces-to duce. he rat :atiwhi 1 Also, I

pressure increases. reduction in rate of pressure increases throughout the upward stroke of the piston and regenerator until the positions shown at 14 and 29 on the right-hand side of Fig. 1 are attained.

The valve stroke will now be described with reference to the cylinder shown on the right-hand side of Fig. 1. At this point, the volume of the chambers 16 and 21 is at the lowest value in the cycle and the maximum relativeportion of the gas contained in these. chambers resides in the cold end at a point below the regenerator 29. The temperature and'volume relationships are controlled by this heat-absorbing ability of regenerator 29, which has now received its maximum amount of'heat, and these relationshipsare such that pressure is near a maximum point of its cycle and volume is at a minimum.

As the piston 14 and regenerator 29 move downwardly, the volume within the chambers increases and regenerator 29begins to move through the gases which have been contained in the cold end of space 21 below the regenerator. At the same time, gases moving into the cylinder above piston 14 flow from space 21 through the regenerator. The effect of gas passing through the regenerator from both causes it to increase the temperature of the. gas at such a rate that the temperature effect on the pressure of the gas to increase the said pressure. is greater than the eflfect of the volume change which tends to reduce the pressure. In other words, in the equation PV=RT, the relative rate of increase in absolute temperature is greater than the relative rate of decrease in absolute pressure.

After a short motion, the pressure begins to decrease, but decreases at a lesser rate than would occur except for the transfer of heat from the regenerator 29 to the gases and relative motion to it, for at all times throughout the stroke, the pressure is therefore higher than at corresponding points of stroke when the piston 14 is. moving in the opposite direction.

This difierence in pressure of the downward stroke of the piston, the pressure being higher at any position of the piston than at the corresponding position of the piston on the upward stroke, is the driving force which operates this engine.

It should also be noted that the prime function of the hot end of the cylinder is to add heat energy to the gas in the cylinder as the gas flows by the hot portions thereof. On the downstroke of the piston, this heat serves to maintain the temperature of the gases in the cylinder; from which work is derived and which results in some reduction in the temperature of these gases. On the upward stroke, heat is transferred to the gases and then to the regenerator in readiness for the next power stroke. To put the matter very simply, the regenerator, which presents no impediment to the flow of gases freely therethrough, still serves the important function of changing the temperature and therefore the pressure in the up por tion of the cylinder, serving to reduce the temperature in the upper portion of the cylinder as its piston moves upwardly just as such temperature would be reduced if a cold body were introduced into the upper portionof the cylinder, while at the same time adding heat and pressure to the upper portion of the cylinder during the downward strokeof the piston because the regeneratonhaving been heated by the passage of hot gases therethrough, now requires that all of the gases passing from the lower portion of the cylinder upwardly be heated as they expand toward the upper portion of the cylinder. This result resembles the introduction of a heated element into the upper portion of the cylinder and piston chamber as the piston starts to descend.

Referring to a single cylinder and to the operation of the piston;therein and within the chamber about the cylinder, while the gases remain within the space provided by. the cylinder and; chamber, the gases are compressed and ex:

panded by the action of the piston and the action of the heating and cooling zones, and during movement ofthe piston, there is the action of the cool regenerator in cooling the gases as the regenerator moves upwardly with the piston and heating the gases passing therethrough as the heated regenerator moves downwardly with the piston.

In the embodiment illustrated in Fig. 1, theregenerator is attached to the piston by a support which passes through slots in the cylinder wall. As the piston rises in the cylinder, the skirt of the piston covers the slot so that only in that portion of the cylinder above the top of the piston is there communication between the space within the cylinder and the annular chamber surrounding it in which the regenerator moves. This action of allowing the piston to complete the establishment of the annular space as it rises, serves'to trap the gas in the cold space in the lower part of the annulus.

In the modification shown in Fig. 3, a single piston engine is illustrated in which the parts are arranged in a simple or compact form and in which there is a small clearance at the top of the piston giving a maximum percentage of gas to transfer from the hot to the cold areas. In this structure, the cylinder 36 is provided with a slot 36a. The piston 37 is provided with a connecting neck 38 securing the piston to a regenerator 39. The piston is connected by rod 40 to the crank 41, and a flywheel 42 is mounted on the power take-off shaft 43. A casing 44 provides a regenerator chamber 45, and it will be noted that the top portion 46 of casing 44 provides a minimum chamber space 47 above the piston 37. Fuel is introduced through the nozzle 48, where it meets preheated combustion air flowing through chamber 49, and the combustion gases flow over the top wall 46 of casing 44 and exit through flue 50. The preheated combustion air is supplied to chamber 49 through the pipes 51 passing through the flue 50.

In the construction shown in Fig. 4, the regenerator moves approximately 60 out of phase with the piston. The effect is to heat the air in the annular space a little earlier in the piston cycle and to cool it a little earlier to increase the work obtained from parts of a given physical size. Good results are obtained when the regenerator is from 60 to 100 out of phase with the piston.

In the specific illustration given, cylinder 52 is imperforate and the piston 53 moves freely within the cylinder, being connected to the crankshaft 54 by the piston rod 55. A flywheel 56 is mounted upon the take-off power shaft 57.

The casing 58 provides regenerator chambers 59 and a top chamber 60 directly above the piston. The regenerator 61 is moved by rods 62 which extend through a partial wall 63 and are connected by pivots 64 to shafts 65 cartried by the crank 54.

Fig. 5 sets out a pressure diagram in which the inner lines outline the work area for the structure shown in Fig. 3 and the outer lines outline the work area for the structure shown in Fig. 4. It will be observed that the out-of-phase relationship shown in Fig. 4 tends to fatten or enlarge the diagram, but since maximum and minimum pressures (and gas temperatures (not shown)) are unchanged, the efliciency is little aifected. More work per cylinder is obtained and, of course, heat input would at one end thereof, means for heating the last-mentioned,

end of said cylinder. and easing, means for cooling the other end of said casing, a fluid-permeable regenerator reciprocable through the fluid contained in said chamber,

and means for reciprocating said regenerator'within said;

4. In a fluid engine, a piston equipped with a. piston,

rod, a cylinder receiving said piston, a casing providing a chamber about said cylinder and communicating with one end of said cylinder, inertia means exterior of the cylinder,

and connected to said piston rod for continuing the IQ;

ciprocating motion of said piston, means for heating the casing adjacent said last-mentioned end of said cylinder, means for cooling the casing adjacent the opposite end of said cylinder, said cylinder being provided with a longitudinally-extending slot, a fluid-permeable regenerator reciprocably movable within said chamber about said cylinder, and means extending through said slot and connecting said piston and regenerator.

5. The structure of claim 4, in which said piston is equipped with a depending skirt for covering said slot during movement of the piston toward the end of the cylinder communicating with said chamber.

6. In a hot gas engine, a pair of cylinders each equipped with a piston reciprocable therein, crankshaft means connected with each piston to constrain movement of the same in an out-of-phase relation with each other, a casing about each of said cylinders providing a chamber communicating with its cylinder at one end thereof, means for heating said last-mentioned end portion of said cylinder and casing, means for cooling the opposite end of said casing, a gas-permeable regenerator reciprocable through the fluid contained in said chamber, and means for reciprocating said regenerator within its chamber in unison with its associated piston.

7. The structure of claim 6, in which the cylinders are slotted and connecting means extend therethrough joining each piston to its associated regenerator.

8. A hot fluid engine, comprising at least one cylinder having a longitudinal slot therein, a piston in said cylinder, casing means providing a pressure-retaining chamber enclosing said cylinder and spaced therefrom to provide an annular chamber communicating with said cylinder at one end thereof, means for heating one end of said pressure-retaining chamber and cooling the other end thereof, a regenerator movable within said annular chamber, a member secured to said piston and extending through said slot for engagement with said regenerator, said piston being equipped with a depending skirt providing a cover for the slot when the piston is in raised position, and inertia means for continuing the motion of said piston.

9. A hot fluid engine, comprising a fluid chamber, fluid filling said chamber, means for heating one end of said chamber and cooling the other end portion thereof, a cylinder in said chamber and spaced from the walls thereof, said chamber communicating with .said cylinder at one end thereof, a piston within said cylinderfor movement toward and away from the heated end of said chamber, a regenerator in said chamber outside of said cylinder and permeable by the fluid of said chamber, a crankshaft equipped with means connecting it to said piston, a chamber about said crankshaft, means for maintaining the pressure therein above atmospheric, means associated with said piston for moving said regenerator concurrently with said piston, and inertia means for continuing the motion of said piston.

10. In a fluid engine, a cylinder equipped with a piston reciprocably mounted therein, a casing about said cylinder providing a chamber connnunicating with the cylinder at 1\ one end thereof, means forheating the last-mentioned end of said cylinderandi casing, means for cooling the other end of said casing, a fluid-permeable regenerator reciprocabl'e-through the fluid contained in said chamber, andmeans for reciprocating said regenerator within said chamber-in-an out-of-phase relation to saidpiston.

ll; Thestructure of claim 10, in which the-regenerate: is moved 6040100 outof phase withthe piston.

12 In a fluid-engine, a piston equipped with a piston rod, acylinder receiving said piston, inertia means exterior of the cylinder and connected to said piston for continuing movement thereof, a casing about said cylinder providing a chamber around the cylinder and a narrow chamber abovesaidpiston communicating therewith and said first-mentioned chamber, means for heating the casing adjacent the open end of: said cylinder and for 13. The structure of claim 12, in which said-regenerator is about 60 out of phase with saidpiston.

1'4; The structure of claim 12, in which said inertia means comprises a crankshaft connected to said piston by a pistonv rod.

References Cited in the file of this patent UNITED STATES PATENTS 445,904 Robinson Feb.- 3, 1891

Images