Pump Device

This invention relates to a pump device for obtaining an intermittent pumping or circulation of a fluid.

Pumping devices are known which circulate gas or liquid. In certain cases it is desired to produce simultaneous circulation of fluid in a number of jars, where the fluid in each jar has no connection with that of another jar. One example of such a case is a multicelled accumulator battery, where air is pumped into the electrolyte, and bubbled up through the electrolyte to cause circulation of the electrolyte. One prior proposal of hitherto used devices for this purpose, is described in Swedish Pat. No. 226.673. Accumulator cells are also an example of a case wherein the circulating medium shall not be taken from outside the jar, but only from within the jar.

It is an object of the present invention to provide a novel fluid pump.

It is another object of the invention to provide a novel battery pump which circulates fluid from within a battery jar.

The pump devices according to the invention have an elastic membrane, which is influenced on its primary side by a variable pressure. When pressure is increased, the secondary side of the membrane initially closes the inlet openings and after that forces the fluid in the pump house out through the outlet openings. The pressure increase is preferably obtained by another pump, a primary one, which generates compressed air in regularly varying pulses. The variations of the pressure can also be transmitted by another medium, for example oil. They can also be obtained by mechanical means. The membrane is suitably designed like a bladder, whereby the inside of the membrane is the primary side and the outside of the membrane is the secondary side. The design of the pump house is preferably worked out in such a way that the distance between its primary and secondary parts is longer at the outlets than at the inlets. It can also be suitable that the membrane, which consists of homogeneous material, is thicker in that part which covers the outlet openings, than in that part which covers the inlet openings.

The invention shall further be described in and by the following statement in connection with the drawings.

In FIG. 1, a preferred embodiment of the invention is illustrated in longitudinal cross-section and in

FIG. 2 an example of an application of the preferred pump is illustrated.

The pump device comprises a pump house with two parts, viz., a primary part 2 and a secondary part 1. The housing parts 1, 2 are held together by a connecting element 4 in the form of a sleeve which is threadedly connected to the primary housing part 2. Between the two parts of the pump house, there is disposed a flexible membrane 3 characterized as a bladder, which along its edge 10 is clamped between the two parts of the pump house. A primary side of the membrane faces the primary part and a secondary side of the membrane faces the secondary part. The primary part 2 of the pump house is provided with channels 6 for connection with a device for generating compressed air pulses with a regular frequency, and also possibly with another pump. The secondary part 1 of the pumphouse is of U-shaped cross-section and includes two inlet openings 8 at an upper portion thereof. The membrane 3 is wrapped around the primary part and extends over the terminal end of the channel 6 and above the inlet openings 8. The secondary part has two inlet openings 8 and one outlet opening 9. The figure shows the pump device in a position of rest, i.e., the primary side of the membrane is no longer influenced by an overpressure. Between the two parts of the pump house, there is a space 7, within which the membrane can expand. The depth of the space 7 between the parts of the pump house is largest at the outlet opening 9 and essentially smaller at the inlets 8. That portion of the space 7 between the membrane 3 and the secondary part 2 may be considered as a working space, the depth of which progressively increases from the inlets to the outlet. The location and number of the outlet and inlet openings can of course be varied within the scope of the invention and in the described embodiment, a number of inlet openings may, for example, be placed in a circle around the secondary part of the pump house. Also, the design of the channels in the secondary part may vary, according to different applications and embodiments. These variations do not influence the principal function of the pump device. Preferably, the membrane is formed of a homogenous material whose thickness is greatest at a region thereof across from said outlet opening.

The operation of the pump device is characterized as follows. Through the channel 6 in the primary part 2 of the pump house, pressure pulses are induced with an overpressure of about 0.1 MPa and a regular frequency of the magnitude 0.5-1.0 Hz. A pressure pulse results in an approximately uniform extension of the membrane 3, which causes a rapid obstruction of the inlet openings 8 by the secondary side of the membrane. Further extension of the membrane has the effect that the fluid in the space 7 inside the pump house is forced out through the outlet opening 9. A hose 5 can be connected to this outlet. The total volume of the outlet opening and the hose ought to be essentially less than the volume of the space 7. When the pressure decreases and the membrane reverts to its initial position, i.e., engaged with the primary part of the pump house, there is at first some resuction of the forced-out fluid, which, however, ceases as soon as the inlet openings are reopened. To decrease the return of the fluid, the outlet opening or hose can be provided with a non-return valve.

FIG. 2 shows a preferred application of the invention for producing electrolyte circulation in a multicell accumulator battery. In FIG. 2 only two cells are shown, but in reality a battery can comprise more than 100 cells. Each cell comprises a jar 11 containing electrodes 12 and electrolyte 13. The pump device 14 according to the invention is located above the electrolyte surface 15 and has, in the example, been shown as installed in the lid of the battery. Thus, the inlet openings of the pump device will be disposed within the space over the electrolyte, while the hose 5, which is connected to the outlet opening 9 terminates near the bottom of the jar. The hose 5 can then be connected to devices for obtaining greatest possible electrolyte circulation. This arrangement avoids the need for sucking-in air from outside the jar to produce electrolyte circulation. Instead, there is only a circulation of the gas present in the respective jars.

Although the invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, modifications, substitutions and deletions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.