FR2513311A1 - THERMAL MOTOR - Google Patents

Abstract

The low temperature heat engine, which is operated by solar radiation, serves in particular for driving water pumps. It essentially comprises a hermetically sealed diaphragm cylinder (11), to which the vapour of a low-boiling medium is fed from the solar collector (1). Control is performed by way of a valve device (3, 4) which for overcoming the top and bottom dead centre of the diaphragm cylinder functions with the aid of an energy-storing spring (9). The spring is tensioned at each stroke and held by a permanent magnet (6), until the stored energy is so great that it is torn away from the permanent magnet, thereby reversing the valve so that even with very slow reciprocating movements the dead centre of the diaphragm cylinder is overcome. The device can be used in conjunction with a water pump for rough operation in agriculture over long periods of time without maintenance.

Description

 The present invention relates to a heat engine which can be actuated by solar radiation to drive a water pump.

There is a need for a solar powered water pump for agricultural applications, particularly in the livestock sector, which can be used practically in countries where a relatively large incidence of solar radiation is manifested. . Such a pump should advantageously have a power of several hundred watts and be capable of pumping water from great depths. For more than 100 years, attempts have been made to develop a practical method of using solar energy to pump water. However, no suitable system was designed for the difficult conditions encountered in agricultural applications. Many suggestions were made, but none reached an industrial stage and none could be implemented at an attractive cost price. . In 1864, Bernard Mouchot built an installation in Algiers that pumped water by solar energy (PR Sabady,
Haus und Sonnenkraft, page 23, Helion Verlag, Munich, 1979).

 In 1870, Ericson built an installation similar to the one mentioned above in the USA.

 In 1880 Robert Schulz obtained German patent No. 14078 for a solar powered engine.

Other engines followed, notably that built by AG Aneas in 1910 in Pasadena (USA), and that of Schumann in 1911 in Cairo (H.Rau, Heliotechnik, pages 190 and following,
Udo Pfriemer Verlag, Munich, 1976).

More recently, solar water pumping test projects have been carried out in many southern countries, such as "Nadje" in Senegal, "Onersol 'in Nigeria," Segal "in
Senegal, "Ouagu" in Upper Volta, "Chinguetti" in Mauritania and "Ejido Bahia" in Mexico City (Informationswerk Sonnenenergie, Volume 4, page 277, Udo Pfriemer Verlan, Munich, 1977). The technical principles of known engines can be divided into two main groups.

 First, there are motors that collect solar energy in parabolic collectors that vaporize the water to power a steam engine. Secondly, there are installations with flat collectors in which a low boiling agent such as freon is vaporized to actuate a steam engine or a turbine. Installations with parabolic collectors have the disadvantage that on the one hand the mirrors must be continuously adjusted with respect to the sun, which requires great efforts, and on the other hand the mirrors are liable to be dirty. As a result, mirrors have to be cleaned frequently, which makes it almost impossible to use such devices in remote locations without frequent maintenance.

 However, installers with flat collectors are not affected by problems of fouling and adjustment with respect to the sun, but difficulties remain which have not yet been eliminated with regard to sealing, in particular the loss of the agent of weak point d 'boiling.

 Both types of engines use steam to power a steam engine or a turbine. The use of a conventional device has the disadvantage that a first mechanical effort is necessary to transform a linear movement (piston in a cylinder) into a rotary movement (eccentric flywheel) which, in the pump (deep hole with pump piston) must again be transformed into a linear movement. The double transformation reduces the efficiency of the device and considerably increases the expenses.

 In turbine installations, the rotational movement is transmitted to a generator which in turn drives the electric motor of the pump. It also reduces yield and increases costs.

 In addition, all known installations are relatively large since it is not profitable to build installations with a power of several hundred watts.

However in many agricultural installations, it is precisely this power that is necessary. For example, a 200 watt pump can supply approximately 2000 sheep with water.

On the other hand, it should also be remembered that many wells in the most arid regions of the world do not contain a large amount of water. Consequently the use of a large installation is often not justified and is not valid financially.

 It is concluded that there is not currently on the market a pump powered by solar energy and which can be mass produced.

 The present invention relates to a water pump suitable for use in agriculture. The pump according to the invention can be made to small dimensions, for example with a capacity of 200 watts, and it is suitable for irrigation and water supply in small and medium-scale agricultural enterprises, in particular for the development of regions.

 According to the present invention, there is provided a heat engine comprising means for channeling the vapor of a liquid agent to a hermetically sealed and reciprocating pump containing an alternately displaceable element, where the vapor expands to release energy , and out of which the expanded steam is then discharged, an engine in which the control of the expansion and discharge process is effected by means of a set of valves comprising an inlet valve for the introduction of steam and a valve outlet for the discharge of expanded steam, said valve assembly using elastic means to abruptly reverse the valves so that it is possible to pass through the neutral position of the movable element alternately even during a slow stroke movement .

Other advantages and characteristics of the invention will be highlighted in the following description, given by way of nonlimiting example, with reference to the appended drawings in which:
- Fig. 1 is a vertical sectional view of an embodiment of a pump actuated by solar energy in accordance with the present invention,
- Fig. 2 is an elevational view on an enlarged scale of a set of valves of another embodiment of a pump actuated by solar energy similar to that of FIG. 1,
- Fig. 3 is a partial sectional view and
in elevation, of a valve actuation device of the pump of FIG. 2, and
- Fig. 4 is a cross-sectional view of the valve of the pump of FIG. 2.

 The pump shown in the drawings comprises a solar collector 1, a steam dome 2, an intake valve 3, an outlet valve 4, a balance 5, permanent magnets 6 and 7, a control slide 8 associated with springs 9 and 10, a main cylinder 11 associated with a diaphragm 12 and a diaphragm plate 13, a connecting rod 14, a sliding bearing 15, a working lever 16, a back pressure cylinder 17, a condenser pump 18, a condenser 19, a guide pulley 20 associated with a traction cable 21 leading to a well pump 22.

 The group components are connected by conduits 23 to 28. In the solar collector 1, a fluid (which can have a low boiling point of around 10 C) is heated and reaches the vapor dome 2 from which it is channeled to the main cylinder 11 via the conduit 23 and the intake valve 3.

 In the main cylinder 11, the steam expands and actuates the well pump 22 via the diaphragm 12, the connecting rod 14 and the working lever 16, using the traction cable 21 and the guide pulley 20.

As indicated, the lever 16 is anchored at one end, it is connected by its other end to the cable 21 and it is pivotally mounted on the connecting rod 14 by the sliding bearing 15.

 During this process, the control spring 9 is applied against the balance 5 by the control slide 8.

 it is in turn prevented from descending by the permanent magnet 6 since the latter stops the balance 5 until the spring 9 is placed in its lowest position and that the increase in pressure forces the balance 5 has deviate from the permanent magnet 6. The energy accumulated in the control spring 9 reverses the movement of the balance 5 so that it now comes to abut against the permanent magnet 7 and remains in this position (as indicated on the drawings), the outlet valve 4 being open at the same time.

By means of this outlet valve 4, the expanded vapor now flows through the conduit 27 into the condenser 19. The vapor is then cooled and it is condensed by the water pumped by the well pump 22.

 This condensate collected in the condenser 19 is now pumped via the conduits 26 and 25 into the solar collector 1 under the action of the diaphragm pump 18 which is actuated by the working lever 16 at each stroke of the latter. Via a conduit 28, the pressure established in the condenser 19 is transmitted to the pressure cylinder 17. This has the effect, when the outlet valve 4 is opened, of discharging the main cylinder 11 because the two cylinders ll and 17 are at the same pressure. As a result, the rod 14 can more easily wait for its upper end of travel and force the balance 5 to move away from the magnet 7.

 Consequently the balance 5 moves until it comes into contact with the magnet 6 to initiate another cycle. In this way, the possibility of immobilization or loss of capacity is reduced in case the temperature in the condenser 19 increases above the boiling point of the fluid at atmospheric pressure due to insufficient cooling.

 The force returning the rod 14 to its upper limit position is gravity acting on the rods of the well pump 22. This main cylinder 11 therefore contains a single-acting diaphragm pump.

The pump according to the invention shown in FIG. 1 can offer one or more of the following advantages:
- no effort to be exerted on a transmission, an eccentric, flywheels, generators or turbines,
- loss of fluid avoided by the use of diaphragms
- the engine starts without assistance at the start of exposure to sunlight since the valve, even for the slowest movement, surely crosses the neutral point of the cylinder,
- the machine works without lubrication and there is little or no leakage since all the components which are mobile and exposed to steam are equipped with diaphragm for sealing, - possible use even with slow piston pumps
at great depths, and possible adaptation to different
types of pumps.

 Now considering Figs. 2 to 4, it can be seen that another embodiment of a set of valves used for operating a pump of a type similar to that shown in FIG. 1.

 In Fig.2, there is shown a base 98 on which is mounted a main cylinder 100 of a construction similar to that of the cylinder 11 described above and containing a diaphragm.

 At its upper end, the cylinder 100 is connected to a conduit 102 which is joined by a connection to bypass conduits 104 and 106. The conduits 104 and 106 lead respectively to valves 108 and 110. The valve 108 is connected from l 'other category of a conduit 112 which leads to a condenser similar to 19 in FIG. 1.

 The valve 110 is connected on the other side to a conduit 114 which leads to a solar energy collector similar to 1 in FIG. 1.

 The valves 108 and 110 and their associated conduits are mounted on a support plate 116 also mounted on the base 98.

 A connecting rod 118 extends downward from the cylinder 100 through the base 98.

 In addition, a mounting bar 120 extends downward from the lower side of the base 98. An actuating lever 122 is pivotally mounted between its ends on the bar 120.

The connecting rod 118 is pivotally mounted by its lower end on one end of the actuating lever 122.

 Between the connecting rod 118 and the articulation pivot on the bar 120, the actuating lever 122 is also connected divotably to a piston rod 124, directed downwards and which is coupled to a condensate pump similar to the pump 18 of FIG. 1.

 On its side opposite to the connecting rod 118, the actuating lever 122 is pivotally connected to a rod 126 directed upwards.

The rod 126 passes through a hole in the base 98 and it extends upward to a point adjacent to the valves 108 and 110. At a point adjacent to its end opposite the connecting rod 118, the lever d actuation 122 is connected to a set of pump rods similar or identical to the set of rods 20, 21, 22 of FIG. 1. In addition, the end of the lever 122 which is opposite to the connecting rod 118 may be provided with an additional weight to facilitate the downward stroke of the actuating lever 122 as described below.

 A pendulum 128 is pivotally mounted by an end between the valves 108 and 110 on a spindle which is firmly fixed in the plate 116.

At its end opposite to the valves 108, 110, the balance 128 is connected to one end of a spring 130 (shown diagrammatically) and the other end of the spring 130 is connected to the rod 126. In addition the rod 126 is also connected to a spring 131, the other end of which is connected to the cylinder 100.

The spring 131 acts, in cooperation with the spring 130, to center the rod 126 in its mounting in the base plate 98 in order to reduce the friction contact with this plate 98.

 Two stops 132 are mounted on the support plate 116.

Furthermore, as shown in FIG. 3, the pivotally mounted end of the balance 130 comprises a pair of circular end flanges 134 as well as an intermediate cam portion 136 provided with upper and lower flat surfaces.

 Each valve 108, 110 comprises, as shown in Fig.4 an elastic projection 138, starting from the valve body. Each sail 138 contains a valve stem 140 the outer end of which is mounted in a block 142. On the outside of the block 142, the projection 138 supports a wheel 144 mounted for rotation.

 At its inner end, the valve stem 140 is provided with a valve head 146 arranged so as to come into tight contact with a seat 148. The wheels 144 are pushed into contact with an edge of a corresponding flat surface of the cam part 136 by the elastic projections 138.

In service, in the position shown in FIG. 2, the rod 126 is in its upper limit position and the balance 128 is pushed by the spring 130 in contact with the stop 132.

In this position, the cam 136 is turned upwards and one edge of its upper flat surface bears against the wheel 144 of the valve 108 and compresses the corresponding elastic projection 138. Consequently, the block 142 and the associated valve stem 140 are moved towards the body of the valve 108 and the valve head 146 is thus moved away from its seat 148.

 In this way the valve 108 is opened when the rod 126 is in its upper limit switch. In this position, the actuation lever 142 is also in its upper limit switch and has completed a pumping stroke.

The opening of the valve 108 discharges gases from the cylinder 100 via the conduits 102, 104 and 122. up to a condenser such as that described with reference to FIG. 10 to then reach a solar collector.

 The diapragm of the cylinder 100 returns to its rest position. Essentially this movement is produced by the force of gravity bringing down the right end (looking at Fig. 2) of the actuation lever 122. The actuation lever 122 pivots around its support on the bar 120.

This action pushes the connecting rod 118 in order to return the diaphragm to its initial position. Simultaneously he raises the rod 124 to activate a condensate pump.

 In addition, the rod 126 is lowered so that the point of connection of the spring 130 with the rod 126 arrives below the pivot of the pendulum 128. This causes the elongation of the spring 130 so that, when the lever 126 has crossed the neutral position, the spring is extended so that it causes the pendulum 128 to pass suddenly from the upper application position against the upper stop 132 as far as the lower position, shown in phantom, from application against the stop lower 130.

 This action causes the opening of the valve 110 in a manner analogous to the opening of the valve 108 described above.

This allows a fresh charge of pressurized steam from a solar collector to pass through the conduits 114, 106 and 102 to enter the pump 100 and deploy the connecting rod 118. A deployment of the connecting rod 118 causes the lowering of the rod 124, in order to actuate a condensate pump, and the transfer of the rod 126 into its upper position shown in FIG. 2.

 Also, when the fixing part of the spring 130 on the rod 126 has passed the neutral position and when the spring 130 has been extended sufficiently, this spring 130 suddenly swings the pendulum 128 into the position shown in solid lines where it comes into contact with the upper stop 132.

 To ensure that the pendulum 128 does not tilt until the rod 126 has reached its upper limit position, one can provide a magnet 150 which slightly slows the tilting upwards of the pendulum 128 under the impulse of the spring 130 This reduces the risk of the pump blocking in a position in conditions of low solar radiation.

 The magnets of the embodiments described above could be replaced by equivalent attraction means such as suction cups, pulse couplers or "velcro" links.

 Other modifications and variants can be envisaged without departing from the scope of the invention. For example, the diaphragm can be replaced by an equivalent alternative element such as a piston sliding in a cylinder as for a piston pump.

Claims (12)

R E V E N D I C A T I O N S  1. - Heat engine comprising means for channeling the vapor of a liquid agent in a hermetically sealed and reciprocating pump containing an alternately movable element, in which the vapor expands to release energy and out of which the expanded vapor is then discharged, motor characterized in that the control of the process, of expansion and discharge, is carried out by means of a set of valves comprising an inlet valve for the introduction of steam and an outlet valve for the discharge of expanded vapor, said set of valves using elastic means to abruptly reverse the valves so that it is possible to cross the dead center of the displaceable element alternately, even during a slow stroke movement .  2. - A heat engine according to claim 1, characterized in that it uses the energy stored by an elastic means by compression of this elastic means at each stroke so as to store the energy of the elastic means and then suddenly release the stored energy.  3. - A heat engine according to claim 2, characterized in that the means for opening and closing the valves is arranged to be stopped by an attraction means until the elastic means is sufficiently compressed to overcome the force. of attraction of the attraction means in order to immediately release the energy stored in the elastic means and to release the means for opening and closing the valves.  4. - A heat engine according to claim 3, characterized ence that the attraction means is a permanent magnet.  5. - A heat engine according to one of claims 3 or 4, characterized in that the means for opening and closing the valves is in the form of a balance which is pivotally mounted at one end and which is arranged to so as to pivot between first and second positions when a respective valve is open.  6. - A heat engine according to claim 5, characterized in that the elastic means comprises two springskelicoldaux mounted around a sliding spindle, in that this sliding spindle is arranged so as to move in association with the reciprocating element and go through a hole  of the balance wheel and in that the coil springs are  mounted on each side of the pendulum.  7 ~ A heat engine according to claim 1, characterized  in that the means for opening and closing valves  includes a pendulum connected to a spring, encloses the spring  is connected to an arm that can be moved alternately so that  form a control element beyond neutral point,  in that the arm can be moved alternately between  first and second extreme positions so that when  said arm approaches its first or second  extreme position, the spring is extended to pull  suddenly the pendulum in its opposite position  8. A heat engine according to claim 7, characterized  in that there is also a means of attraction for  additionally hold the balance in its position  opening the intake valve to assist this  valve so that it remains open during the entire ad cycle  mission of the pump. 9. Thermal engine according to any one of claims 1  to 8, characterized in that the expanded fluid, after having  left the reciprocating pump, arrives in a condenser to  its liquefaction.  lo.-Heat engine according to claim 9, characterized in  what the condenser acts on the opposite side of the element to  reciprocating so that in the discharge position  of the valve assembly, there is the same pressure on the  two sides of the reciprocating element.  ll.-Heat engine according to any one of claims  1 to 10, characterized in that the condensed steam is recycled  by a pump which is switched on when the  the reciprocating element.  12.-Heat engine according to any one of claims  1 to 11, characterized in that the expanded steam is, in service  cooled by water pumped by the heat engine.  13. A heat engine according to any one of claims  1 to 12, characterized in that it comprises a solar collector  arranged to receive incident solar radiation and to  thus vaporize the liquid. 14.- A heat engine according to claim 13, characterized in that the solar collector is a flat plate solar collector. 15.- A heat engine according to any one of claims 1 to 14, characterized in that the reciprocating pump is a diaphragm stern and in that the reciprocating element is a diaphragm.