US 2988264 A
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Description (OCR text may contain errors)
June 13, 1961 JEAN-LEON REUTTER 2,988,264
ALTERNATING MOVEMENT SYNCHRONQUS COMPRESSOR 2 Sheets-Sheet 1 Filed Aug. 20, 1959 Q ML June 13, 1961 Filed Aug. 20, 1959 JEAN-LEON REUTTER ALTERNATING MOVEMENT SYNCHRONOUS COMPRESSOR 2 Sheets-Sheet 2 States The present invention relates to a vibrant operating compressor electromagnetically maintained, this compressor being more particularly intended to be used for compressing freezing fluid for refrigerator equipment.
According to the invention, the compressor comprises a mobile unit comprising two opposed magnets arranged axially, this mobile unit being connected by adjusting springs to a magnetic housing delimiting at least some of the generatrices of a tube surrounding said mobile unit and comprising, at its middle part, a coil intended to be supplied with alternating current, the width of this coil being appreciably equal to the width of a magnetic part separating the two magnets from the mobile unit which is connected to at least one compressor piston sliding in a fixed cylinder.
Various other characteristics of the invention will moreover be revealed by the detailed description which follows.
Forms of embodiment of the purpose of the invention are shown by way of non-restrictive examples, in the 1 attached drawings.
FIGURE 1 is an elevation-section of one form of carrying out the invention.
FIGURES 2 and 3 are partial diagrammatical sections taken substantially along the line IIII of FIGURE 1.
FIGURE 4 is an axial section familiar to FIGURE 1, of an alternative.
FIGURE 5 is a partial section on a larger scale of a modification.
In the form of embodiment shown in FIGURE 1, the compressor comprises a tight-fitting casing 1 comprising an inlet pipe 2 and discharge pipes 3. This casing contains a compressor which comprises a magnetic housing 4 in which there is a coil 5 fed with alternating current. A mobile unit is made up by two magnets 6, 7 and magnetic arm'atures 8, 9 and 10.
The polarities of the magnets are, for example, those indicated by the letters N and S in the drawings.
Two springs 11 and 12 act on the mobile unit, these springs being mounted between a central part of the magnetic housing 4 and flanges 13, 14 integral with the mobile unit. The latter slides in a tube 15 of non-magnetic metal integral with the magnetic housing. Rods 16 fixed to the mobile unit actuate pistons 17 able to slide in cylinders 19 which also comprise flap-valves 20 supported by covers 20a that can slide in relation to the cylinders 19 against the action of springs 100 which connect the covers 20a to the end of the tight-fitting casings 101 supported by the cylinders 19 and connected to the discharge pipes 3.
The pistons 17, like the flap-valves 20, are at least partly made of deformable material, so that the admission of low pressure fluid from the interior of the casing 1 to the cylinders is effected by deformation of the peripheric edge of the pistons 17, then the fluid driven out by these pistons passes around the flap-valves 20.
When, for some reason or other, the stroke of the pistons is too great and they consequently come into contact with the flap-valves 20, this has the effect of causing the covers 20a to slide, so that no damage either to the pistons or flap-valves can occur.
The magnetic housing 4 can be produced in various ways. More particularly, it can be made of cast iron,
and in this case, revolves, or, as shown in FIGURE 2 it can be made of an assembly of steel sheets 102, all cut out in similar ways and assembled together around the tube 15 in which the mobile unit slides.
The magnetic circuit can also be made up of several fagots 103, 104, and 106, also formed by an assembly of steel sheets, these fagots being evenly distributed around the tube 15, as shown in FIGURE 3.
As shown in FIGURE 1, the arrangement of the magnets 6 and 7 is so chosen that they are placed in opposition, their south poles, for example, facing each other. In this manner, when the apparatus is at rest, that is to say, when no current is passing into the coil 5, the lines of force of the permanent fields produced by the magnets close, as shown by dotted lines. When the coil is supplied with alternating current, the flux of the latter, at the moment of starting up, closes by the magnetic circuit and the central polar part, as shown by broken lines.
During the first alternation, the magnet circuit is polarized. Thus, the poles n and s are produced on either side of the coil.
In' this case, the mobile unit is impelled towards the left of the figure. The flux of the coil and that of the magnet 7 combine for producing the displacement. At this moment, the lines of force follow the pathway shown by broken lines. At the following alternation, the polarities n and s are reversed and the mobile unit is impelled to the right, for the same reason as the one explained above.
To obtain a suitable working of the apparatus, the springs 11 and 12 are advantageously adjusted so as to impart to the mobile unit an actual frequency that is less than the frequency of the alternating feed current of the coil.
This is intended to compensate for the variations of counter-pressure due to the fluid compressed by the pistons 17, which counter-pressure has the effect, when it increases, of increasing the resilient stress applied to the mobile unit, and hence, the movement of the latter approaches a resonant movement when the counter-pressure of the driven fluid increases, that is to say, when the working rate of the compressor become important.
Figure 4 shows an alternative in which we also find the fluid-tight casing 1 which comprises the low pressure inlet pipe 2 and the discharge pipe 3 at high pressure, for the fluid that has been compressed. The magnetic housing is formed as in FIGURE 1.
In this alternative, the rod 16 is fixed on one side only of the mobile unit and actuates two opposed pistons 17, 18 able to slide in a cylinder 19 which carries two flapvalves 20, 21. The fluid arriving through the inlet pipe 2 is thus compressed inside the casing 1, which, in this case, acts as a high pressure fluid tank.
The other end of the mobile unit carries a rod 22 which penetrates through a stuffing-box 23 into a cylinder 24. The two extreme faces 25 and 26 of this cylinder each have a valve 27 or 28 kept closed by a spring 29 or 30.
The rod 32 carries a piston 31 able to slide in the cylinder 24, the interior of the latter being connected to the inlet pipe 2 by a small section tube 32.. The cylinder 24, like the cylinder 19, is integral with the magnetic housing 4.
In this embodiment, the springs 11 and 12 are made so as to impart to the mobile unit an actual frequency greater than the frequency of the feed current of the coil 5.
The compressor described works as follows. At rest, it should be considered that an equal pressure prevails in the whole of the compressor, as well as at the moment of starting up, which is the case for refrigerating machines. At the beginning of working, the pump formed by the cylinder 19 and its pistons does not do any Work and thus has no influence on the actual frequency of the mobile unit of the compressor, whereas the cylinder 24 acts as a spring and exerts a relatively high resilient force on this mobile unit. When the pressure drops in the intake pipe 2, the cylinder 19 exerts a resilient force which goes on increasing, but at the same time, the pressure lowers in the cylinder 24, the fluid that this cylinder contains flowing slowly through the tube 32. The latter is of small section, otherwise the cylinder 24 would no longer act as a spring for the mobile unit. The actual frequency of said mobile unit diminishes and the power produced by the electro-magnetic motor increases, hence also the amplitude of the movement of the mobile unit. It follows that the piston 31 bears at the end of its stroke on the valves 29 and 30, and that the high pressure fluid penetrates into the cylinder 24. The actual frequency of the mobile unit then increases and the power diminishes. There thus occurs a state of equilibrium for the limit amplitude for which the piston 31 bears exactly against the valves 29' and 30.
In proportion as the compression rate in the cylinder 19 increases, the amplitude diminishes and the cylinder 20 empties, tending to cause a fresh increase of amplitude.
It will be noticed that while the frequency belonging to the feed current diminishes, for example, the mean pressure lowers automatically in the cylinder 24 so that the desired resonance again occurs. In other words, the piston 31 only opens the valves 29 and 30 for a lower pressure. It should be noted that the lower pressure that may prevail in the cylinder 24 is the one that prevails in the inlet pipe 2.
To increase the extent of possible adjustment, the cylinder 24 can be provided with a small pump capable of lowering the pressure until empty, if so required. This alternative is shown in FIGURE and comprises a cylinder 40 mounted in the extreme wall 25 of the cylinder 24 and into which a rod 41 penetrates integral with the piston 31, the entry into the cylinder 40 taking place through a stuffing-box 42, with a certain amount of clearance to enable the fluid to pass through. The rod 41 carries a piston 43 which cooperates with a valve 44- for driving the fluid towards the low pressure side of the compressor through a small section tube 45 which connects in the inlet pipe 2 of the compressor. The cylinder 24 can thus be emptied until it is almost completely empty.
It will thus be seen that the compressor described comprises, in short, a compression cylinder 19 and a regulating cylinder 24 in which a mean pressure is set up at such value that the amplitude of the mobile unit of the compressor remains uniform when the compression rate varies.
The invention is not restricted to the examples of embodiment, shown and described in detail, for various modifications can be applied to it without going outside of its scope.
1. An alternating movement synchronous compressor comprising a substantially tubular shaped magnetic housing of magnetic material, said magnetic housing including an annular recess substantially at the middle portion thereof, a coil winding supplied with alternating current, enclosed in said annular recess, a thin tube of non magnetic material fitted inside said magnetic housing, a shuttle slidably mounted in said tube and comprising a median cylindrical part of magnetic material the width of which corresponds substantially to the width of said recess of the magnetic housing, two permanent magnets respectively connected to said median part on both sides thereof and having their magnetic axis extending longitudinally with respect to the shuttle and their polarities of same name one in front of the other, two magnetic cylindrically shaped members connected with said two permanent magnets, said shuttle further carrying cup shaped flanges at both ends and pistons, two loaded springs being interposed between said flanges and said magnetic housing and cylinders carried by said housing aligned with said shuttle and in which said pistons are slidably mounted.
2. An alternating movement synchronous compressor as set forth in claim 1 in which said spring interposed between said flanges and said magnetic housing are loaded to impart to the shuttle a natural frequency higher than that of the alternating current supplying said coil winding, and one of the cylinders carried by said magnetic housing is provided with regulating members intended to maintain substantially constant the amplitude of movement of said shuttle.
3. An alternating movement synchronous compressor as set forth in claim 2, in which said compressor is enclosed in a sealed casing the inside pressure of which corresponds to the pressure at the exhaust of the compressor and in which said cylinder provided With regulating members comprises a duct opening at the middle portion thereof, said duct communicating with the inlet of the compressor and also two valves respectively mounted at both ends of the cylinder, each said valve having a protruding portion engaged by the piston driven by the shuttle when the amplitude thereof exceeds a determined value thus causing the pressure inside the casing enclosing the compressor to be in part at least applied inside said cylinder.
References Cited in the file of this patent UNITED STATES PATENTS 2,721,453 Reutter Oct. 25, 1955 FOREIGN PATENTS 675,958 Great Britain July 16, 1952 730,803 Germany Jan. 18, 1943 1,084,252 France Jan. 18, 1955 1,085,894 France Feb. 8, 1955