Patent GB-1122586-A (GB)
Title: Electro-hydraulic transducer
IPC: G21D7/02
Filed: 1965-08-26
Abstract: An electro-osmotic pump comprises a container divided into chambers by a porous diaphragm sealed to the container, a non-aqueous ionizing liquid filling the container, electrodes substantially inert to the liquid on opposite sides of the diaphragm and means for applying an electrical potential between the electrodes to cause the liquid to tend to flow through the pores of the diaphragm, the liquid having the characteristic that it remains substantially stable over a period of at least two hours of continous application of the potential.  The liquid preferably has a dielectric constant between 5 and 100 and contains a hydrocarbon portion and also a polar group which may be a nitrile, as in butylnitrile, carbonyl, as in ketones such as cyclohexanone, an aldehyde, as in benzaldehyde, an alcohol, as in methanol or isopropanol or a nitro group, as in 2-nitro-propane. Organic or inorganic redox material such as quinone-hydroquinone or ferriferrocyanide-ferroferrocyanid may also be present to protect the carrier liquid from decomposition.  The pumping effect may be enhanced by treatment of the diaphragm to produce large ionizing or ion exchange groups on the pore surfaces, e.g. a fritted glass diaphragm may be preliminarily treated with an alkaline solution of tetrapropyl ammonium hydroxide or other alkyl or aryl ammonium hydroxide.  The diaphragms may be formed of ceramic, synthetic plastics, rubber, paper or cellulose.  The potential applied may be direct, up to several hundred volts, or alternating.  Alternating potential may be used to produce pulses of pressure to transmit shock waves to the medium to which it is applied Fig.10 (not shown).  A number of unit pumps may be connected in parallel to increase the liquid flow Fig.4 (not shown), or in series Fig.5 (not shown).  The pump may be used is a voltage regulator, the electrodes being connected through rectifiers having a high forward resistance to the high voltage transmission lines. Variation of voltage in the line causes movement of the liquid in the pump to move a piston in a hydraulic cylinder, which in turn moves a tap selector arm altering the resistance in the primary circuit of a transformer Fig.6 (not shown).  The pump may be used as a governor, e.g. for diesel engines, the voltage of a generator driven from the engine being applied to the pump electrodes to produce a movement of liquid which is used to control the engine speed Fig.7 (not shown). Fig.9 (not shown) shows the application of two similar pumps to a fluid switching device, flow from a main conduit being directed to one or other of two branch conduits according to whether one or the other pump is operative, using the Coanda effect.  Fig.11 (not shown) shows the use of two pumps in series to perform addition and subtraction functions of a computor according as the voltages across the two pairs of electrodes produce pressure differences reinforcing or opposing each other. Fig.13 (not shown) shows use of a pump, in a manner similar to that shown in Fig. 7, to control the speed of an automobile, the voltage being generated by a generator attached to the rotating cable of the speedometer, and the fluid pressure produced acting to restrict the flow of petrol to the carburetter.