GB1489683A - Apparatus for obtaining the presence in a receiving device of fluid under two different pressures for successive alternate periods of time - Google Patents

Abstract

1489683 Apparatus for applying pressure to the body P W MATTHEWS 4 Nov 1975 [25 March 1975] 12400/75 Heading A5R [Also in Division F2] Apparatus for applying two different pressures to a part of the body for successive alternate periods of time comprises a first fluid conduit 10 connected to a source of fluid 1 under superatmospheric pressure, a second fluid conduit 7 connected to a receiving device for transmitting pressure to a part of the body, a supply valve 11 (see Division F2) having a first operative position in which communication is provided between the fluid, conduits 10 and 7 and a second operative position in which communication is provided between the second fluid conduit 7 and an exhaust path 12 to atmosphere, a control device 14 for actuating the supply valve and first and second timers 16 and 17 connected to the control device and arranged such that upon termination of a period determined by the first timer the control device actuates the supply valve into one of its operative positions and initiates running of the second timer, and upon termination of a period determined by the second timer, the control device causes the supply valve to shift into its other operative position and initiates running of the first timer. The receiving device may be a double-walled sleeve, Fig. 6, adapted to receive a patient's limb such that when fluid under pressure is applied to the space defined between the walls, pressure is exerted on the limb. The control device may be a fluid logic device comprising two 3-input OR/NOR logic elements 1 and 2, the OR outputs being X<SP>1</SP> and X<SP>2</SP> and the NOR outputs being Y<SP>1</SP> and Y<SP>2</SP> respectively. The timers are actuated by application of pressure to diaphragm switches 19, 21 connected to outputs Y<SP>1</SP> and Y<SP>2</SP> respectively and the valve is actuated by pressure applied alternately to inlets 11a and 11b connected to outputs X<SP>2</SP> and X<SP>1</SP> respectively. When timer 16 reaches the end of its set period, it opens a valve 16a connected to input C<SP>2</SP> of the control device, thereby causing the control device to change over to its other steady state and actuating the valve 11 and the other timer 17. The timers may be mechanical timers or air-bleed timers.