US2267280A - Device for conveying fluids - Google Patents

Description

' Dec. 23, 1941. c. KUHNEL DEVICE FOR CONVEYING FLUIDS Filed Oct. 14, 1938 Patented Dec. 23, 1941 UNITED STATES PATENTLQFFICEY DEVICE FOR CONVEYING FLUIDS Carl Kiilmel, Berlin-Charlottenburg, Germany, assignor to Patentverwertungs Gesellschaft mit beschrankter Haftung Hermes, Berlin, Germany, a corporation of Germany Application October 14, 1938, Serial .No. 234,999

GermanyOctober 15, 1937 7 Claims, "(01. 230-160) The present invention relates to a device for I conveying fluids.

In conveying fluids, devices are often employed which have one or more flexible walls or diaphragms, In this case these walls are reciprocated by a driving device; for instance, by a crank mechanism, an electric oscillating armature drive or the like, whereby the working chamber volume of the device is alternately increased and decreased. A suction conduit and a pressure conduit are connected to a suitable point of the working chamber. In the case of a direct drive cooperating with such flexible walls difliculties are encountered if a considerable super-atmospheric pressure is to be overcome during the pressure stroke. In this case it may happen that the portion of the flexible wall lying between the hub, arranged in most cases in its central portion, and the firmly clamped wall edge warps out of the desired shape owing to the super-atmospheric pressure. To avoid this, de-

vices have hitherto been employed in which the desired motion is imparted to the operating portions of the flexible wall by reinforcing plates and corresponding articulated rods connected forces acting during the pressure stroke on the wall between the point of application of the driving force and the peripheral support of the edge cause a deflection of the wall only toward the working chamber. In this manner the material of the-wall supports itself during the pressure stroke, so that no strengthening means are necessary to prevent the wall from warping away from the opposite wall of the working chamber.

The particular shape of the flexible wall is determined by the forces (inner pressure and outer driving force) acting on the wall.

The invention may be used in connection with metallic diaphragms as well as with arrangements whose flexible. walls are made of rubber or of a similar resilient material. The use of rubber diaphragms presents the advantage that -the ring stresses occurring in the material upon the reciprocating motion may be easilyabsorbed owing to the elasticity of the material so that the risk of fracture is considerably reduced. According to the invention the rubber wall and the wall of the working chamber opposite thereto are given such a shape that 'during the pressure stroke the volume of the working chamber is gradually reduced towards a given point, preferably towards-the portion of the working chamber in which are arranged the suction conduit and the pressure conduit. Since strengthening plates need not be at all arranged on the side of the rubber portion facing the working chamber, the

working chamber of the device may be utilized,

cannot occur in operation. In case reinforcements are necessary in some points elements made of less resilient material, such as sheet iron, metal wires, fibrous material or the like may be vulcanized in the rubber diaphragm, care being preferably taken in this case to maintain its surface defining the working chamber elastic so that it may snugly flt against the opposite wall of the working chamber at'the end of the compression stroke. The "device according to the invention may, for instance, be so designed that the working chamber is enclosed by the rubber wall and a stationary wall opposite thereto, in

the central portion of which are arranged the suction conduit and the pressure conduit. However, itis also possible to design the gas-compressor or pump according to the invention with two opposite walls of rubber or of a similar resilient material.

In many cases homogeneous rubber may be employed for the driving parts. Under certain conditions, it may; however, also be advantageous to arrange in the construction of the rubber walls layers differing in elasticity; for instance, in such a manner that the parts of the .rubber wall adjacent to the working chamber modifications of the compressor according to the invention,

7 third form of the invention,

Fig. 3 shows partly in sectional elevation a- Fig. 4 shows a sectional elevation of Fig. 3 at right angles to that in Fig. 3, and

Fig. 5 represents a fourth embodiment also in a sectional elevation.

Fig. 1, more particularly, shows a gas compressor which may, for instance, beemployed in a domestic refrigerator. The compressor consists substantially of a'stationary wall I and a flexible wall 2 which may be raised and lowered with respect to wall I and consists of rubber or a similar substance and is provided with a neck or hub portion 3. In engagement with the latter is a rod 4 which may be reciprocated, for instance, by a crank mechanism or the like (not shown). The walls I and 2 are held together at their outer rims by clamps 5 provided with screws 6 exerting a pressure on clamping elements I. In the central portion of the wall i are arranged a suction conduit 8 and a pressure conduit 9. i8 denotes cooling ribs by means of which the waste heat of the gas compressor is dissipated to the atmosphere. The other parts of the refrigerator are not shown in Fig, 1.

The working chamber III of the compressor enclosedby the walls I and 2 has the greatest volume in the position of rest shown. During the pressure stroke the average diameter D of the working chamber It decreases gradually-owing to the particular shape of the walls I and 2-towards the central portion of wall I where the conduits 8 and 9 are arranged, as is shown by the various positions of the rubber wall 2 indicated in dotted lines. The shape of walls I and 2 just referred to and as apparent from Fi 1 is as follows. The hub portion 3, the clamped marginal portion, and the intermediate portion of the movable wall, formed of an integral body of rubber or the like, has a continuous inner surface. The wall body 2 is cup-shaped when in the relaxed position shown in Fig. 1, so that its inner surface is concavely curved away from -pressor.. 8 denotes the suction conduit and 8 the pressure conduit which pass through the wall II. In this case the compressor is secured to a stationary plate 14 with the aid of a pressure rim I5 and clamping screws I6. Also in this case the diameter of the working chamber III decreases during the pressure stroke owing to the special shape of the walls II and I2 gradually tocompressor consists, as shown in Fig. 1, substantially of a stationary wall 2| and amovablerubber wall 22 provided with a neck 23. The walls2| and 22 are held together by means of clamping screws 24 and clamping plates 25. 26 denotes a connecting rod whose lower part 21 is attached to the rubber body .22, 23 by vulcanization. The

upper end of rod 26 is pivoted on crank pin 28 fixed on the disk 29 which is driven with the aid of a shaft 3| and pulley 30 by an electric motor 34. In this embodiment the rubber body is caused to oscillate in the plane of the drawing upon the rotation of the disk 29. In the end positions, both of the suction stroke and pressure stroke the driving rod 26 is, however, perpendicuthe opposite inner surface of the rigid and stationary wall I. The inner surface of wall I is also substantially continuous and has a flat shape. Consequently, the inner wall of the wall body 2, having no projections or the like, is flattened out during the pressure strokes of the crank-operated rod 4 and at the end otthe stroke is contiguous with the inner surface of the stationary wall I substantially throughout the entire extent of both walls. The entire wall body 2 is' self-supporting and its thickness increases from the clamped and stationary marginal portion towards the reinforced hub portion 3, as is apparent from Fig. 1.. It will be noted from Fig. 1 and any of the other figures that the entire intermediate portion of the body 2 lies within an angle or triangle having its apex at the point of attack of rod 4 and determined by any two opposite points at the clamped periphery of the marginal portion, this angle being directed from its apex towards the stationary wall. Due to this design, the intermediate portion of the material of the body is stressed by a compressive force directed mainly from the hub portion 3 towards the clamped marginal portion and towards the surface of wall I. As a result, the working chamber is constrainedly reduced in diameter towards its center as shown by the dotted lines already mentioned.

In Fig. 2, ll denotes the working chamber, II

and I2 the rubber walls enclosing the working chamber and I3 the neck of another gas'comlar to the stationary plate 2|. 32 denotes the pressure conduit and 33 the suction conduit. 40 is a support plate secured to the rod 26 and in engagement with the neck 23.

The gas compressor is driven by the electric motor 34 with the aid of the belt drive 30, 35, 36. On the motor shaft is mounted a ventilator 31 serving to cool the compressor and other parts of the refrigerating apparatus. 38 are cooling ribs arranged at the lower part of the stationary wall 2|. 39 is a support for the compressor. The rubber parts shown in the various embodiments may be so dimensioned that when slackened they just fit in their supporting plates -I (Fig. 1) and I4 (Fig. 2). The rubber parts may also have a larger outer diameter than their supporting plate and be inserted into the plate rim with a corresponding initial tension. In the embodiment according to the invention the suction stroke may under given conditions be extended beyond the normal position of the rubber piston shown so that the rubber parts become stressed in tension in the last portion of the suction stroke.

The flexible rubber wall of the above-described compressors may be composed of various rubber wall 22 and having an elasticity different from that of the main portion of the wall. It may further be of advantage to reinforce the flexible wall by strengthening means, such as the reinforcement GI in Figs. 3 and 4, which are vulcanized in the rubber body.

Fig. 5 shows an embodimentof the invention in which a metallic diaphragm is employed in the construction of the compressor for a refrigerating apparatus. Thecompressor consists substantially of a stationary'body 5| provided with an annular recess the bottom 58 of which forms the stationary wall ofthe pump. From this recess rises a central cone II. the outer surface of ble shape, said flexible wall having a reinforced hub'portion connected with said drive, a marwhich forms the continuation of this stationary wall.

Over this, cone and recess 58 is placed a metal diaphragm 52 forming the movable wall and shaped similarly but not the same as recess driving rod 53 which may be set in motion by a crank mechanism, oscillating armature'drive or the like (not shown) is attached to the central portion of the movable wall 52. A suction conduit 55 and a pressure conduit 55 extending cen trally through con'e 59 and terminating in the upper portion of chamber 51 lead to parts of the refrigerating apparatus not shown. The movable wall 52 is shown by a heavy line in the position of rest corresponding to the end of the suction stroke. An intermediate position of the movable wall is shown in dot and dash lines, from which it will be apparent that the wall is convexly bent on the side facing the working chamber 51 on the suction stroke so that, at the end of the latter, wall or diaphragm 52 lays itself entirely against the contoured surface. 58 of body Owing to the particular shape of diaphragm 52 I warping of portions of it lying between the driving rod 53 and the clamping device 54 is rendered impossible even without the employment of additional strengthening means. The forces acting on the movable wall 52 during thepressure stroke merely cause the wall to assume such a shape as to snugly fit into the annular recessed portion of the stationary body 5| and to thus expel the contents of chamber 51. The invention may also be employed in compressors and pumps in which are employed two movable diaphragms lying opposite to each other. The invention is not limited to the use of a particular material. The movable wall may consist of any of the suitable materials hitherto employed.

What is claimed is: v

1. In a device for conveying fluids, comprising a reciprocatory drive and a container forming a working chamber of variable volume, said container being formed of a stationary wall having an inner surface of substantially invarible shape, and a reciprocatory flexible wall of variable shape, said flexible wall having a reinforced hub portion connected with said drive, a marginal portion firmly connected around its periphery to said stationary wall, and an intermediate por- I tion, said three portions consisting of an integral elastic body having a continuous inner surface which is in contact with said inner surface of said stationary wall substantially throughout the extent of said three wall portions at the end of the pressure stroke of said drive so as to reduce the ginal portion firmly connected around its periphery to said stationary wall, and an intermediate portion, said three portions consisting of an integral elastic body having a continuous inner surface and being shaped to have said hub portion and said marginal portions stand away from said inner surface of said stationary wall when said body is in relaxed position, said inner surface of said stationary wall and said inner surface of said body being shaped relative to each other to be substantially in contact with each other throughout the extent of said three wall portions at the end of the pressure stroke of said drive so as to reduce the minimum volume of said chamber substantially to zero, said intermediate portion of said reciprocatory wall lying substantially within the angle directed towards said stationary wall and determined by thepointofatwith, a stationary marginal portion firmly connected around its periphery to said stationary wall, and an intermediate portion, said three portions consisting of an integral body of compressibly elastic material having a continuous inner surface and being shaped so as to have said latter surface curved away from said flat inner surface of said stationary wall when said body is in relaxed condition, said inner surface of said stationary wall and said inner surface of said body being contiguous with each other substan tially over their entire extent at the end of the pressure stroke of said drive.

4. In a device for conveying fluids, comprising a reciprocatory drive and a container forming a working chamber of variable volume, said container being formed of a movable wall of variable shape and a stationary wallof rigid material having a fiat inner wall surface, said movable wall comprising an integral body of compressibly elastic material cup-shaped so as to have a hollow inner surface when in relaxed condition, said body having a reinforced hub portion connected minimum volume of said chambersubstantially to zero,said intermediate portion of said reciprocat'ory wall lying substantially within the angle directed towards said stationary wall and determined by the point of attack of said drive at said hub portion and any two opposite points of the periphery of said marginalportion.

2. In a device for conveying fluids, comprising a reciprocatory drive and a container forming a working chamber of variable volume, said container being formed of a stationary wall having an inner surface of substantially invariable withsaid drive to reciprocate therewith, a'marginal portion firmly secured around its periphery to said stationary wall, and an intermediate por-- tion of a wall thickness increasing in the'radial direction from said marginal portion towards said hub portion so as to cause said drive to maintain said material in said intermediate portion under a compressive force during the pressure'stroke of said drive.

5. In a device for conveying fluids, comprising a reciprocatory drive and a container forming a working chamber of variable volume, said container being formed of a movable wall of variable shape and a stationary wall of rigid material having a flat inner wall surface, said movable wall comprising an integral body of compressibly elastic material cup-shaped so as to have ahollow inner surface when in relaxed condition, said inner surfaces of said stationary wall and of said shape, and a reciprocatory flexible wall of variabodyrespectively being shaped relative to each other to be substantially in contact with each marginal portion towards said hub portion so as to cause said drive to maintain said material in said intermediate portion under acompressive force during the pressure stroke of said drive.

6. Ina device for conveying fluids, comprising a crank mechanism and a container forming a working. chamber of variable volume, said con-v tainer having a stationary wall-and a reciprocatory flexible wall, said flexible wall consisting of' a body of compressibly resilient substance and having a reinforced central hub portion, an intermediate portion surrounding said hub portion and a marginal portion, said marginal portion being firmly connected along its periphery with said stationary wall, a rigid member having one end connected with said hub portion and .its other end engaging said crank mechanism so as to move said-hub portion towards said stationary wall during the pressure stroke of said mechanism and to place said hub portion substantially in contact wtih said stationary wall at the end of said stroke, said body when in relaxed position being shaped to curve away from said stationary wall so as to gradually decrease the diameter of said chamber towards its center during said pressure stroke, and said intermediate portion having a wall thickness increasing in the radial direction from said marginal portion towards said hub portion so as to be prevented from warping away from said stationary wall during said pressure stroke.

' 7. In a device for conveying fluids, comprising a reciprocatory driveand a container forming a working chamber of variable volume, said container being formed of a rigid stationary wall and a movable -wa1l, said stationary wall having an inner surface of a shape composed of a cone and an annular groove surrounding the base of said cone, and said movable wall consisting of metal and havinga cone-and-groove shape following approximately the shape of the inner surface of said stationary wall, said movable wall being firmly and tightly connected around its periph-- ery with said stationary wall and having a reinforced hub connected with said drive for pressing the groove-shaped portion of said movable wall into the groove-shaped surface portion of said stationary wall, said groove-shaped portion of said movable wall lying within an acute angle directed towards said stationary wall and having its vertex at said hub and its legs passing through 0 any two oppositepoints of the periphery of said movable wall.

CARL

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