ELECTRIC PUMP

Abstract: A pump drives a diaphragm with a vibrating solenoid armature of the sort often used for solenoid water valves. The vibrations arise from half wave rectified ac. The output side of the diaphragm communicates with anti-parallel duck beak (or duck bill) valves, to provide high pressure and low pressure ports. Virtues are simplicity and cost. A pump body 3, housing the upper components, guides the armature 2, supports the coil 1, mates with a valve body 9 which houses the lower components, and clamps downward on the edge 5″ of the diaphragm 5. Its lower extremity 10 is bell-mouthed to match the valve body and to form a chamber for the diaphragm. A valve holder 8 within the valve body presses the exit valve 6 and has an extension tube which contains the inlet duck bill valve 7. The valve holder also clamps upwards on the edge 5″ of the diaphragm. The lower end of the armature may have a forced-on resilient buffer piece 22, which is integral with the central part of the diaphragm 5, to impinge vibratingly on a central portion of the valve holder 8 in order economically and simply to reduce shocks, wear and noise.

Description: This invention relates to a pump for fluids, eg hot or boiling water, steam or hot coffee, and aims to provide adequate performance without excess bulk, weight, number of parts or cost price. Accordingly, the invention considers the state of the art FR-A-2 262 711, i.e. including a vibrating armature driven by an alternatingly energized solenoid, a diaphragm vibrated by the armature, and parallel fluidways which each communicate with the diaphragm and contain oppositely directed passive one-way valves, preferably of the type often known as duck bill valves or duck beak valves. The solenoid is vibrated by being arranged for intermittent or ac energization, whereby the diaphragm executes an oscillatory movement. Greatly preferred is that somewhere in the vibrating system is a return spring to a rest position. The energization from the rest position is preferably ac through half-wave rectification, eg a single diode, as defined in the pre-characterising portion of Claim, 1. The solenoid can be of the same type as that used for conventional electrically-operated fluid valves, and the invention proposes a very simple assembly and manufacture, which is characterised in Claim 1. The sole Figure of the drawing illustrates further features and advantages, as described below. Referring to the Figure a solenoid coil 1 drives an armature 2 which can slide up and down in a non-conductive, non-magnetic plastics guide upwards from the rest position shown, against the bias of a return coil spring 4. Communicating with the space 5′ below the diaphragm 5 are two oppositely directed similar duck bill valves 6 and 7 held by a valve holder 8, in which diaphragm 5 can also be secured by its non-vibrating peripheral, strengthened edge 5″. The lower end of the armature may have a forced-on resilient buffer piece 22, which is integral with the central part of the diaphragm 5, to impinge vibratingly on a central portion of the valve holder 8 in order economically and simply to reduce shocks, wear and noise. The valve-holder by a conduit extension 21 within valve body 9, actually contains the inlet valve element 7. The valve holder is an insert in a valve body 9, in which is attached, e.g. welded or bolted along an annulus a bottom part 10 which may be integral with the guide. The valve body 9 and the pump body 3, thus attached, form the housing for the entire pump apart from the solenoid and its magnetic circuit. The attaching causes the valves 6, 7 to be clamped, as well as the edge 5″. Coil 1 is fed at an insulated faston terminal 11, preferably by ac mains 13 through a single diode 12, or other varying electrical feed. The coil has an easily magnetizable yoke and gap, eg a rectangular external yoke (not shown) of two crimped together L-sectioned pieces, each having a respective tubular extension 23, 24 within the coil, separated by a magnetic gap 25 adjacent an end of armature 2. The coil and its former may be encapsulated on the outside and above, by material 14. Body 3 snaps at 27 into a hole 26 in piece 23. When the coil is energized, the armature rises (to decrease the effective magnetic gap) against spring 4. When the coil is next less energized, or preferably de-energized, the armature falls due to return spring 4 lengthening. This up and down represents one vibration stroke or cycle of the pump, and will be repeated at 50 Hz (or other supply frequency). The consequent up movement of diaphragm 5 each cycle creates a sub-atmospheric "vacuum" in space 5′, which closes valve 6 by forcing the edges of a rubber slit sealingly together. On the other hand, similar valve element 7 is opened by the vacuum, thereby communicating the vacuum with a low pressure port 16. Similarly, each down movement of the diaphragm increases pressure at 5′ which opens valve element 6 and pushes fluid to a high pressure port 15. Therefore pressure is raised at 15 and lowered at 16, to create the pumping action which is economically provided by this invention. The valves 6 and 7 only move by flexures in the vicinity of their resilient slits at the end of tapering cross-sections, and so consume little energy opening or shutting. Moreover, quite small pressure differences can open or close the slits. However, other types of one-way passive valve may be preferred for some purposes.

Claims: 1. An electrically actuated pump for fluids such as hot or boiling water, comprising a vibrating armature driven by an alternatingly actuated solenoid, a diaphragm, two fluid passageways of which each is in communication with the diaphragm and contains a passive one-way valve element, these two valve elements having opposite senses of blocking as seen from the diaphragm, the different parts being relatively assembled along the longitudinal axis of said pump, the coil (1) of the solenoid being disposed on the axis of the armature (2) which vibrates piston-like in operating said diaphragm (5); wherein a single body (3) of the pump performs a guiding function, supports the coil (1), guides the longitudinal vibrations of the piston-like armature (2), holds the non-vibrating part (5″) of the diaphragm (5) in place, provides with a bell-mouthed end (10) an upper part of a chamber which accommodates the vibrating part of the diaphragm (5), and ensures the closure of said upper part of said chamber, these functions being enabled by virtue of the cylindrical shape of the pump body (3), and wherein said bell-mouthed end (10) is shaped to fit matchingly with the profile of a valve body (9) containing said valve elements (6, 7); characterized in that a valve holder (8) carrying the one-way valve elements (6, 7) is disposed between the bell-mouthed lower end (10) of the pump body (3) and the valve body (9); one surface of said valve holder (8) receives the non-vibrating part (5″) of the diaphragm and thereby forms a pumping space (5′), said valve holder (8) fitting into the valve body (9), the admission valve element (7) of the two (i.e. that permitting inwardly directed flow) being housed in a conduit (21) which forms part of the valve holder (8) and is located within the valve body (9), an inlet port (16) being also formed integral with the valve body (9) to be communicative with the conduit (21). 2. Pump according to Claim 1, characterized in that a part of the valve holder (8) clamps the fixed part (5″) of the diaphragm to the pump body (3), clamps the other, exit valve element (6) directly against the valve body (9) and also cooperates with the pump body (3) to assist the assembly and ensure the closure of the assembled said components of the pump. 3. Pump according to Claim 1 or 2 wherein the holder (8) in clamping the fixed part (5″), is itself clamped by the valve body (9). 4. Pump according to any of Claims 1-3 wherein an upper closed extremity of the pump body (3) receives a return spring (4) acting on the armature (2), and has an external extremity (27), which snaps into a hole (26) in a magnetic circuit (23, 24) for the solenoid and thereby in turn into a hole in the solenoid coil former. 5. Pump according to Claim 4 wherein the magnetic circuit comprises crimped together L-shaped pieces having tubular inward extensions (23, 24) separated by a magnetic gap (25).

Inventors: BUFFET, JEAN CLAUDE
Applicants: EATON S.A.M.
Application year: 1988
Main classification: F04B17
IPC codes: F04B15, F04B43