WO1987007683A2

WO1987007683A2 - Electromagnetic diaphragm pump

Info

Publication number: WO1987007683A2
Application number: PCT/EP1987/000312
Authority: WO
Inventors: Hans-Martin Lohberg; Detlef Lange
Original assignee: Lohberg Hans Martin; Detlef Lange
Priority date: 1986-06-14
Filing date: 1987-06-12
Publication date: 1987-12-17
Also published as: WO1987007683A3; AU7583987A; DE8616123U1

Abstract

Diaphragm pump with a delivery chamber (13) into which lead inlet and outlet valves (2, 3) and which is closed off by an elastic diaphragm movable by the armature (50) of an electromagnet (4) against the force of a return spring (45). During narrowing of the air gap (6) by the momentary supply of current to the electromagnet (4) the delivery chamber (13) is enlarged and during supply of power the delivery chamber (13) is reduced in size by the force of the return spring (45), and a high delivery pressure is exerted on a medium. In an end position the return spring (45) presses a closure element into the outlet channel (12) in a leakproof manner. A circuit for automatic operation is described.

Description

Electromagnetic diaphragm pump

The invention relates to a diaphragm pump, in particular for fluids, with a delivery chamber which is preceded by an inlet valve and an outlet valve and which is closed on one side by an elastic membrane which is connected to an armature of an electromagnet which is connected to a return spring is burdened.

In diaphragm pumps of known type, the armature of the electromagnet is arranged in connection with the diaphragm, so that when the magnet is energized, the pumping space is pressed together by the electric force. This creates a pump pressure as long as the current is applied. For a constant pressure, a practically constant energization is therefore necessary, which is why the entire design of the magnet and its energization is provided for a 100% duty cycle and a relatively low delivery pressure is possible according to the corresponding current. Each time the armature path is at an end, the current is briefly switched off, so that an armature return spring also brings the membrane back and liquid flows into the delivery chamber. In addition to the relatively low delivery pressure, there is a disadvantage that if a vacuum is present on the outlet valve, liquid is sucked through the pump.

It is an object of the invention to disclose an electromagnetic diaphragm pump which, with an electromagnet of the same size and with the same power loss as known pumps, produces a significantly higher delivery pressure.

The solution to the problem is that the armature of the electromagnet is arranged in connection with the membrane st that with a minimal armature gap when the armature is tightened, the delivery space is largest and the return spring is dimensioned and arranged such that it is under such a prestress when the armature gap is open that a predetermined minimum delivery pressure arises in accordance with the membrane cross section, and that when the armature gap is closed The armature gap in the de-energized electromagnet is under such a pretension that a predetermined maximum delivery pressure is created.

Advantageous embodiments are in the subclaims ang eg.

With such an arrangement, the magnet is only briefly against the spring force when the armature is brought into the open position by the spring and the entire delivery volume is removed, with the most possible force that can be achieved by magnetic saturation of the armature actuated, with new liquid flowing into the delivery chamber. This current supply can be carried out very briefly with high current, with the same power loss as in known systems, so that a correspondingly high spring force can be overcome, which results in a correspondingly high delivery pressure.

In order to avoid destruction of the magnet in the unintentional impulse operation with a rapid sequence, a known switch-off is provided by a temperature reduction.

The control of the current pulses for the generation of an approximate permanent high pressure is expediently carried out by a position switch which indicates the open armature state. The magnetic excitation takes place advantageously with a Current pulse of defined voltage and duration. After a particularly advantageous circuit, which avoids an excessive shock load on the available voltage source, it is possible to take the energy from a capacitor circuit that is slowly recharged during the pause in the current flow, whereby the energy content of the charged capacitor corresponds to the energy requirement of the electromagnet for each pulse corresponds to a pulse, so that a resonant circuit is formed when the capacitor is coupled to the coil of the magnet, which provides a rapid rearrangement of the energy between the capacitor and the inductor. Switch-off losses can also be largely avoided with the circuit arrangement if the connection is disconnected at the appropriate point in time of the voltage minimum on the capacitor and the energy is then fed back into the capacitor.

A preferred area of use for the pump is the injection of fuel or fuel additives, such as water or alcohol, into internal combustion engines. In these applications, there is suction in the overrun valve at the exhaust valve. Advantageously, the diaphragm pump can be designed in such a way that a closing element is attached to the plunger of the armature and closes the outlet of the delivery chamber when the armature is fully open. If the electromagnet is not actuated in overrun mode, no liquid will pass through the suction of the motor of the pump.

In an advantageous manner, the diaphragm pump with the suction lock can also be used as a controllable injection pump for internal combustion engines, the armature j ewei ls covering a defined path by suitably short measurement of the current pulse and a corresponding volume of liquid, ie fuel, is sucked in and then deploys. An additional controlled valve for fuel metering is not necessary. Such a controllable injection pump is preferably provided for each cylinder of the engine. There is no central pump.

An advantageous construction with a central magnet arrangement and a suitable control is shown in FIGS. 1-6-.

Fig. 1 shows a vertical section through a

Diaphragm pump;

Fig. 2 shows an exhaust valve enlarged;

Fig. 3 shows an inlet valve enlarged;

-Fig. 4 shows a top view of the pump body;

Fig. 5 shows a section through the anchor enlarged;

Fig. 6 shows a drive circuit;

Fig. 7 shows a diaphragm spring membrane.

In Fig. 1, a diaphragm pump is shown, which is largely rotationally symmetrical. An inlet valve (2) and an outlet valve (3) are screwed into a pump body (1) and are connected to an essentially flat, cylindrical delivery chamber (13) via connecting channels (11, 12). The end of the delivery space is covered with a membrane (14) made of elastic material, preferably rubber or plastic. The membrane (14) extends on all sides beyond a sealing edge (15) on which it is held by an annular pressure body (16). This is part of the Mang etkr ei s it of the electromagnet ⁽ 4 ⁾ , the housing (41) with an annular groove (141) holds the pressure body (16) ufid is screwed onto the pump body (1). The magnetic circuit is guided via the housing (41) and a core (43) to the working air (6), from which the armature (50) extends into one cylindrical recess (161) of the pressure body (16) with a small air gap on all sides. The winding (42) of the magnet is arranged between the core (43) and the housing (41).

5, the armature (50) rests with its end face (55) on the membrane (14). For axial guidance, the armature has a guide pin (51) which is guided through the core (43) - before FIG. 1 -. An abutment (46) of the magnet armature or the pump is attached to the end of the pin (51). The other side of the compression spring (45) is supported in a cap (44) fastened at the end to the housing (4) under pretension. In or on the cap (44), a position indicator (7), which is expediently a switch with a switching thesis, is arranged, which picks up and signals the position of the armature (50) on the abutment (46) which moves with it, when the Air gap has the almost open or closed state.

Wi e Fig. 4 shows, the discharge channel (12) is guided centrally into the delivery chamber (13). The central connection (121) of the discharge channel (12) widens in a conical countersink (122). In this fits an approach (152) - si e. Fig. 5 of a locking part les (52), which with a threaded approach through a punched out (141) in the middle of the membrane (14) and screwed to the plunger-like anchor (50) is. Sealing surfaces (54, 55) on the closing part and on the armature seal the membrane. In order to avoid a high line-shaped load on the membrane during the armature movement, the contours of the armature (50) and the closing part (52) follow the sealing surfaces (54, 55) and are rounded off flat. The valves (2, 3) are each constructed from the same parts as screw nipples, in the cylindrical interior of which is closed by a perforated sealing plug (23, 33), each loaded with a spring (22, 32) Ball (21, 31), depending on the working direction of the valve, nipple or plug end is installed.

The parts of the magnet and the pump can be manufactured so precisely without any special manufacturing measures, so that an adjustment of the position of the armature and the remote voltage is unnecessary. A defective membrane (14) can easily be replaced by screwing the housing (41) to the pump body (1) and the closing and armature part.

Since the spring force is the smallest when the armature gap is open, the armature is slightly tightened and the magnetic energy in the air gap is converted well into mechanical spring energy, which in turn is converted into pump energy.

Fig. 6 shows a circuit arrangement for the automatic operation of the diaphragm pump, which is suitable for energy-saving optic excitation of the magnet of the diaphragm pump. The winding (42) is supplied with the supply voltage (U) when the contact (71) of the switch (7), FIG. 1, is closed. When switching off, the current of the winding (42) from the switching end of the winding (K1) passes through a first diode (D1) via a first connection (A1) into the capacitor (C), where the energy is saved. The capacitor (C) is preferably dimensioned such that it is charged to a multiple of the supply voltage (U). With all further switch-on operations, a second one is now connected in parallel to the first contact (71) Contact (72) closed, which connects the capacitor (C) to the winding (42) at its second winding end (K2), a magnetization due to the high voltage of the capacitor (42) supplied when the winding (42) is switched on. C) causes. Until the energy is discharged from the capacitor (C), a second diode (D2) prevents current from flowing back to the supply line. Only when the capacitor (C) is discharged, does further current drop via the second diode (D2) into the winding (42) of the magnet. The switching points of the contacts (71, 72) determined by a suitable hysteresis give automatic operation in order to achieve delivery with a predetermined minimum pressure which the return spring applies in the switched-on position.

Of course, the contacts (71, 72) can be replaced by electronic circuit elements. Esp. The switching elements can also be controlled by a pulse generator for a predetermined time. The circuit arrangement is expediently fed via a thermal switch (TS) which is expediently installed in the winding. If the diaphragm pump is used in an injection arrangement of an internal combustion engine, the power supply is routed via a normally closed contact of a thrust operating switch (SBS) actuated by a vacuum box (UP), so that there is no valve flow in the thrust operating as the supply and close the discharge channels when there is no magnetic actuation.

7 shows a membrane (14) which simultaneously forms the return spring (65) for the armature. It is designed as a disc spring and for determining the suitable spring characteristics and for determining the restoring forces Appropriately provided with wavy concentric impressions (66) in the two end points of the anchor position. Steel or spring bronze is particularly suitable as the Fed ermat eri a L, for example copper-ber lli um-bronc e, whereby the selection depends on the corrosiveness of the medium to be pumped. A combination of a metallic disc spring with a plastic or rubber membrane can also be used if the medium to be pumped requires it.

Claims

Pat claims

Diaphragm pump, especially for liquids, with a delivery chamber (13), which is preceded by an inlet valve (2) and an outlet valve (3) and which is closed on one side by an elastic membrane (14), which is equipped with an armature ( 50) of an electromagnet (4) is connected, which is loaded with a return spring (45, 65)), characterized in that the armature (50) of the electromagnet (4) is arranged in connection with the membrane (14) so that with a minimal armature gap (6) when the armature (50) is tightened, the conveying space (13) is largest and the return spring (45, 65)) is dimensioned and arranged in such a way that it is under such an angle when the armature gap (6) is open Biasing means that a given minimum delivery pressure is created according to the membrane cross-section, and si e when the armature gap (6) is closed when the electromagnet is de-energized is under such a voltage that a given maximum delivery pressure is created.

2. Diaphragm pump according to claim 1, characterized in that the delivery chamber (13) is a flat cylindrical space, on the sealing edge (15) of which the diaphragm (14) is pressed with an annular pressure body (16).

3. Diaphragm pump according to claim 2, characterized in that the pressure body (16) is part of the magnetic force flow path of the electromagnet (4) which is screwed onto the pump body (1) coaxially to the delivery chamber (13) and the pressure body (16 ) keeps centered.

4. Diaphragm pump according to claim 3, characterized in that the el ekt romagn et si ch e pressure body (16) on the housing (41) of the electromagnet (4) and an inner core (43), the di e coil (42) surrounds, extends to the armature gap (6) and from this the armature (50) extends concentrically with a small all-round gap into the pressure body (16).

5. Diaphragm pump according to one of the preceding claims, characterized in that on the armature (50) a Schli eßtei l (52) is fastened, which with a sealing surface, preferably a sealing cone (152), the j lewei armature gap (6) corresponding to a corresponding sealing surface, preferably a conical countersink (122), is arranged opposite one another and, starting from the sealing surface or the countersink (122), a discharge channel (12) to the outlet valve (3) and / or a supply channel (11 ) leads to the inlet valve (2).

6. Diaphragm pump according to claim 5, characterized in that the Schli eßtei l (52) through a punched (141) in the membrane (14) coaxially and the Schli eßti el (52) is screwed into the armature (50) and that Schli eßtei l (52) and the armature (50) have parallel sealing surfaces (54, 55), between which the diaphragm (14) is tightly clamped, and the surfaces of which are then beveled to the sealing surface (54, 55) or rounded diverging from the membrane (14).

7. Diaphragm pump according to one of the preceding claims, characterized in that the core (43) has a central bore in which the armature (50) by means of a guide pin (51) is axially displaceably mounted.

8. Diaphragm pump according to claim 7, characterized in that the spring (45) is a compression spring which is supported on the one hand at the end of the pin (51) which lies opposite the armature (50) by means of a first abutment (46) and on the other hand on the housing (41) via a cap-shaped second abutment (44).

9. Diaphragm pump according to claim 1, characterized in that the membrane (14) which is formed as a plate spring is a return spring (65) which preferably carries concentric undulating impressions (66).

10. Diaphragm pump according to claim 9, characterized in that the return spring (65) consists of steel or spring bronze.

11. Diaphragm pump according to claim 8 or 9, characterized in that a position switch (7) on the electromagnet (4), preferably on the second abutment (44), is arranged, the di e position of the armature (50) with its switching sensor. or the first abutment (46) and is arranged with its, preferably hysterical, switching points so that a switchover takes place with an open or almost closed air gap (6).

12. Circuit arrangement for controlling a diaphragm pump, which can be actuated by an electromagnet (4) with an armature (50) against the force of a return spring (45), with a winding (42) of the electromagnet (4) via a contact (71 ) is controllably connectable to a voltage source (U), characterized in that the contact-end winding end (K1) of the winding (42) is connected via a first diode (D1) to a capacitor (C), the second connection of which to di e voltage source (U) is guided, and the first connection (A1) is connected via a second contact (72) working in parallel to the contact (71) to the second winding end (K2) of the winding (42), which is connected via a second diode (D2) the voltage source (U) is connected.

13. Circuit arrangement according to claim 12, characterized in that the capacitor (C) is dimensioned in its capacity so that when the contact (71) is opened a voltage across the capacitor (C) occurs which is several times, e.g. three times the voltage of the voltage source (U).

14. Circuit arrangement according to claim 12 or 13, characterized in that the contacts (71, 72) in front of the armature (50) are actuated and they are so hysterical that they switch in each case in predetermined end positions of the armature.

15. Circuit arrangement according to one of claims 12 to 14, characterized in that the voltage source (U) is connected to the winding (42) via a thermal protection contact (TS) which is arranged in the winding (42).

16. Circuit arrangement according to one of claims 12 to 15, characterized in that the voltage source L e (U) via a fuel cut-off contact (SBS), which is actuated by a vacuum element (UP), which is arranged in the intake line of an internal combustion engine, with the winding (42) is connected and the diaphragm pump a metering pump for fuel or an additive therefor is arranged on the internal combustion engine.