WO2016026670A1

WO2016026670A1 - Dosing pump with dosing screw

Info

Publication number: WO2016026670A1
Application number: PCT/EP2015/067571
Authority: WO
Inventors: Peter Schlumpf
Original assignee: Peter Schlumpf
Priority date: 2014-08-22
Filing date: 2015-07-30
Publication date: 2016-02-25
Also published as: CH710010A1

Abstract

In the case of a dosing pump (1) comprising a drive unit (8) and a dosing head (3), wherein the dosing head (3) has an outlet opening (16) for a liquid to be dosed and has a dosing pin (13); wherein the dosing pin (13) is equipped, at a dispensing end, with a dosing screw (14) for delivering the liquid in the direction of the outlet opening (16), which dosing screw is arranged at least partially in a delivery path (15) of the dosing head (3); and wherein the dosing pin (13), at a drive input-side end, is operatively connected by way of a coupling device (12) to a drive output shaft (11) of the drive unit (8) and is driven by the drive unit (8), it is provided according to the invention that the dosing pin (13) is mounted so as to be displaceable along the axis of rotation of the drive output shaft (11) relative to the outlet opening (16), such that said dosing pin can be placed into a closed position and into an open position, wherein, in the closed position, the outlet opening (16) is closed, and in the open position, the outlet opening (16) is open.

Description

Dosing pump with dosing screw

TECHNICAL AREA

The invention relates to a metering pump with a metering screw for the metered delivery of liquids.

TECHNICAL BACKGROUND

Various metering pumps with a metering screw are known which are particularly suitable for medium to high viscosity liquids, e.g. Adhesives are used. However, a common problem is that the known metering pumps often dribble after each dose. Another problem is that the cleaning of the known metering pumps is very expensive due to the complicated dosing. This is particularly disadvantageous when successively different liquids are to be dosed.

From US5046666, US6234358, US6691895 and US20100059552 metering pumps are known, for example, each having a metering screw for conveying the liquid to be metered. No. 5,046,666 describes a metering pump in which a spiral is accommodated eccentrically in a spiral-like cavity. Rotate the spiral causes the suction and delivery of a liquid from an overlying reservoir.

US6234358 describes a metering pump with a metering screw arranged in a cylindrical conveying passage, in which the liquid is fed sideways through an opening in the conveying passage.

US6691895 describes a similar metering pump in which two liquids are fed laterally into the conveyor, which are then mixed in the conveyor and finally ejected through an outlet opening. In advance of the conveying direction, the slope of the screw conveyor decreases.

US20100059552 describes a metering pump with screw conveyor, in which the outlet opening can be closed with a spring-loaded sealing plate. An opening and closing of the outlet opening is dependent on the fluid pressure, which is built up by rotation of the screw conveyor. The liquid is supplied via a supply line from an external reservoir in the feed passage.

An object of the invention is to improve the known dosing pumps with metering screw. Another object is to provide a drip-proof metering pump which prevents dripping of the liquid to be metered. The metering pump according to the invention comprises a drive unit and a metering head. The metering head has an outlet opening for a liquid to be metered and a metering pin, wherein the metering pin is provided at a front ie discharge end with a metering screw for conveying the liquid in the direction of the outlet opening, which is at least partially disposed in a conveying passage of the metering. The metering pin is operatively connected at a rear end, ie drive end, via a coupling device to an output shaft of the drive unit and is driven by the drive unit. By means of the coupling device, the metering screw can be rotated in a conveying direction in order to allow the liquid to be metered to emerge from the outlet opening. Next, the dosing is slidably mounted along the axis of rotation of the output shaft relative to the outlet opening. The dosing can thus be brought by its displaceability along the axis of rotation in a closed position and an open position, wherein in the closed position, the outlet opening is closed and opened in the open position. The displaceability of the dosing pin makes it possible to close the outlet opening with the tip of the dosing pin before and after dispensing the desired amount of liquid, so that dripping is efficiently prevented.

In one embodiment, the coupling device may be configured such that by rotation of the output shaft in a conveying direction of the metering pin is brought only by translation from the closed position to the open position and only subsequently set in rotation. By actuating the metering pump, therefore, the rotation of the output shaft in the conveying direction only in a translational movement of the metering pin to the rear, ie along the rotation axis in the direction of the drive-side end of the metering implemented so that the outlet opening is released for the liquid. The metering pin is then in its open position. After completed translation of the metering pin is automatically rotated by further rotation of the output shaft in the conveying direction in rotation and moves the liquid by means of the screw conveyor through the conveyor to the outlet opening and if provided by a hollow needle dispensed on the dosing. After completion of the delivery of the liquid, ie when the delivery rotation is stopped, the direction of rotation of the output shaft is automatically reversed, so that a translational movement of the dosing takes place forward until the dosing is back in its closed position. This prevents dripping of liquid.

It is advantageous that the coupling device for generating the translation has a helical guide slot. In one embodiment of the metering pump, the coupling device may have a first coupling part rotatably connected to the output shaft and a second coupling part displaceable along the axis of rotation, wherein the second coupling piece engages with a guide pin in a helical guide slot of the first coupling piece, to implement a rotation of the first coupling piece in a translation of the second coupling piece along the axis of rotation. The dosing may be connected directly or via a coupling sleeve releasably connected to the second coupling piece, so that the translational and rotary movement of the second coupling piece can be transferred to the dosing.

On the other hand, the output shaft may also have a guide pin, which engages in the helical guide slot of the first coupling piece. In such an embodiment, the first coupling piece is then not rotatably connected to the output shaft, but slidable along the axis of rotation. A second coupling piece can then be omitted.

In some embodiments of the metering pump, the tip of the metering pin can be shaped such that the outlet opening can be closed by the metering pin. The tip may for example have a conical shape, which fits positively into a corresponding conical recess of the outlet opening. On the other hand, the diameter of the metering screw can be made larger than the diameter of the outlet opening and thus close the outlet opening. The metering pin may also have a sealing cap at its tip.

In some embodiments of the metering pump, the metering head can have an integrated reservoir or a feed opening for the liquid to be metered. In general, the integrated reservoir is configured and arranged such that the drive-side region of the metering screw is arranged in the reservoir. If the dosing head has a feed opening, then this is generally arranged in the region of the delivery passage and connected via a line to a reservoir arranged outside the dosing head. In an integrated reservoir, the rear end of the metering pin protrudes through a rear wall of the reservoir and can thus be connected to the coupling device.

In some embodiments of the dosing pump, the dosing head can be releasably connected to the coupling device and a housing of the dosing pump, so that it is easily replaceable. This is particularly advantageous for a metering head with an integrated reservoir and can also be considered as an independent invention. In this way, dosing heads with different liquids can be easily changed as needed. The detachable, replaceable dosing with integrated liquid reservoir can be designed as a disposable dosing, which is suitable for example for sterile liquids and can serve directly as packaging for the liquid. An advantage of such a dosing is that a complex cleaning is no longer necessary. Also, the replaceable dosing head is inexpensive, e.g. Injection molding, can be produced.

The replaceable dosing can be provided with the already described above, slidably mounted dosing, which can be brought into a closed position. A replaceable dosing without displaceable mounted dosing is also possible. In this case, a metering pump with a simpler coupling device for producing the rotational movement (without translation) would be sufficient. The outlet opening of the dosing head (with or without displaceably mounted metering pin) can be closed with a removable or separable closure, for example a cap, foil or the like, which is removed before the use of the metering pump. In all embodiments, the metering pump can be designed as a hand-held metering pump.

Because of the screw conveyor, the metering pump can also be used for the delivery of medium to high viscosity liquids, such as e.g. Adhesives, to be used. The metering pin may have a circumferential flange or a projection in the drive-side area, which serves as a stop for the metering pin on a rear wall of the metering head during replacement of the metering head, so that it is not removed from the metering head. Between the stop and the rear wall may further be arranged a spring to hold the metering in non-operating in the closed position.

In particular, in a releasable dosing in combination with a displaceable dosing, so the spring-loaded Dosing pin with detached resp. removed dosing be held in the closed position.

Incidentally, it is advisable, in conjunction with the metering pump according to the invention or the metering head, to realize the following features alone or in any combination with the aforementioned features:

- The guide slot can be limited on both sides, so that after a predetermined rotation of the output shaft from 25 to 50% of a full revolution, the rotation is transmitted to the metering.

- The length of the guide slot can correspond to about 25 to 50% of a full revolution about the axis of rotation.

- The slope of the guide slot can be selected such that the metering pin is displaceable by 0.5 to 3 mm. - That the outlet opening of the dosing head is provided with a hollow needle.

- That the dosing head via a detachable connection, such as a Luer lock, with different hollow needles or needles is connectable. BRIEF EXPLANATION OF THE FIGURES The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. Show it :

Fig. 1 is a perspective view of a metering pump;

Figure 2 is a section A-A through the metering pump of Fig. 1.

Fig. 3 the metering pump without housing and partially cut;

Fig. 4 is a Detailanischt the dosing in partially cut

Presentation;

5 shows a perspective view of the metering pump from FIG. 1 with decoupled metering head;

Fig. 6 is an exploded view of a coupling device; and

7 shows the metering pin in the closed position (FIG. 7 (a)) and in FIG

Open position (Fig. 7 (b)).

WAYS FOR CARRYING OUT THE INVENTION

Fig. 1 shows a perspective view of a hand-held metering pump 1 for the metered dispensing of liquids. The metering pump 1 comprises a housing 2, in which the drive unit 8 is housed, and at the front end a metering head 3 for discharging the liquid. The dosing head may have a hollow needle 4 at the tip. On the side of the dosing pump, an actuating knob 5 for actuating the dosing pump 1 is arranged in the vicinity of the dosing head 3, which is electrically connected to the Drive unit 8 is connected. In the embodiment shown, the dosing head 3 is designed as a detachable, exchangeable dosing head with integrated liquid reservoir 17, which can be detachably connected to the housing 2 of the dosing pump 1 via a bayonet-type closure 6. A metering pump 1 with a detached metering head 3 is shown in FIG.

Fig. 2 shows a sectional view of the metering pump of Fig. 1 along the section line A-A. FIG. 3 shows the metering pump from FIG. 1 without housing 2 and with partially cut metering head 3. FIG. 4 shows a detailed view of the metering head 3 with cut metering head housing.

In the rear region of the metering pump 1, a battery compartment for a battery 7 is formed, to which the drive unit 8, which in the embodiment shown comprises a DC motor 9 and a transmission 10, adjoins in the axial direction. A coupling device 12 is connected to an output shaft 11 of the drive unit 8.

In the dosing 3 a metering pin 13 is arranged. The metering pin has at the discharge end a dosing screw 14 for conveying the liquid through a conveying passage 15 in the direction of an outlet opening 16 of the conveying passage 15. In the embodiment shown, the metering pin 13 in the dosing head 3 in the axial direction, that is displaceably mounted relative to the outlet opening 16 along the axis of rotation. The dosing 3 has in the shown Embodiment an integrated reservoir 17 on. A direct feed in the liquid in the conveyor 15 is also possible.

In the rear, i.e. drive-side region, the metering pin 13 has a circumferential flange 18, which serves as a stop for the metering pin 13 on a rear wall 19 of the metering head 3 when replacing the metering head 3, so that the metering pin 13 can not be pulled out of the metering head 3. Between the flange 18 and the rear wall 19 may further be arranged a spring to hold the metering pin 13 in the detached dosing head 3 in the closed position (as described below). The spring can also support the displacement of the metering pin in the closed position after the delivery of the liquid.

The metering pin 13 is mechanically connected via its drive-side end with the coupling device 12. Via the coupling device 12, the metering screw 14 can be rotated in a conveying direction to allow the liquid to be dispensed from the outlet opening 16 in the hollow needle 4 exit. In the embodiment shown, the conveying direction seen from the rear is a left-hand rotation of the output shaft. In addition to the rotational movement causes the coupling device 12 upon actuation of the metering pump 1, a translational movement of the metering pin 13 along the axis of rotation. In this case, the metering pin 13 can be brought from a closed position to an open position and vice versa, wherein in the closed position, the outlet opening 16 is closed and opened in the open position, as further below will be explained in detail. The displaceability of the dosing pin 13 makes it possible, after the delivery of the desired amount of liquid, to close the outlet opening 16 directly with the tip of the dosing pin 13, so that dripping is efficiently prevented.

6 shows an exploded view of the coupling device 12 together with the drive unit 8 and the metering pin 13. FIGS. 7 (a) and (b) show a side view of the coupling device, drive unit and dosing head (partially cut). The remaining parts of the metering pump are omitted for clarity. In Fig. 7 (a), the metering pin 13 is shown in its closed position. In Fig. 7 (b), the metering pin 13 is shown in its open position.

The coupling device 12 includes in the embodiment shown a first with the output shaft 11 rotatably connected coupling piece 20 and a second along the axis of rotation slidable coupling piece 21. The first coupling piece 20 is provided with at least one helical guide slot 22, in which the second coupling piece 21 with at least one Guide pin 23 engages. A rotation of the first coupling piece 20 causes first a translation of the second coupling piece 21 along the axis of rotation and then, after the guide pin 23 abuts the end of the guide slot 21, a rotation of the second coupling piece 21. The metering pin 13 is frictionally, for example via a coupling sleeve 24 with the second coupling piece 21st connected, so that the translation and the rotation is transmitted to the metering pin 13.

The guide slot 22 of the first coupling piece 20 is designed such that upon rotation of the output shaft in a conveying direction of the metering pin 13 first a reverse translation (Fig. 7 (b), arrow X), i. a displacement along the axis of rotation in the direction of the drive unit 8, experiences, to bring the metering pin 13 in the open position and the outlet opening 16 to open. After completed translation of the dosing pin 13 is rotated, so that the screw conveyor 14 moves the liquid forward through the outlet opening into the hollow needle 4 of the dosing head 3. When the metering pump 1 is stopped, e.g. by releasing the actuating button, the rotation of the output shaft is reversed for about a quarter turn, so that the metering pin 13 moves forward again in the closed position.

NAME LIST

1 dosing pump

2 housings

3 dosing head

4 hollow needle

5 operating button

6 bayonet lock

7 battery

8 drive unit 9 DC motor

10 gears

11 output shaft

12 coupling device

13 dosing pen

14 dosing screw

15 conveyor

16 outlet opening

17 integrated reservoir

18 flange

19 rear wall

20 first coupling piece

21 second coupling piece

22 guidance course

23 guide pins

24 coupling sleeve

Claims

Dosing pump (1) comprising a drive unit (8) and a dosing head (3), wherein the dosing head (3) has an outlet opening (16) for a liquid to be dosed and a metering pin (13); wherein the metering pin (13) is provided at a discharge end with a metering screw (14) for conveying the liquid in the direction of the outlet opening (16) which is at least partially disposed in a conveying passage (15) of the dosing head (3); and wherein the metering pin (13) is operatively connected to an output shaft (11) of the drive unit (8) at a drive end via a coupling device (12) and is driven by the drive unit (8), characterized in that the metering pin (13) runs along the rotational axis of the output shaft (11) is slidably mounted relative to the outlet opening (16), so that it can be brought into a closed position and an open position, wherein in the closed position, the outlet opening (16) is closed and opened in the open position. Dosing pump (1) according to claim 1, characterized in that the coupling device (12) is designed such that brought by rotation of the output shaft (11) in a conveying direction of the metering pin (13) only by translation (X) from the closed position to the open position and then is set in rotation.

Dosing pump (1) according to one of the preceding claims, characterized in that the coupling device (12) has a helical guide slot (22).

Dosing pump (1) according to one of the preceding claims, characterized in that the coupling device (12) has a first with the output shaft (11) rotatably connected coupling piece (20) and a second along the axis of rotation slidable coupling piece (21), wherein the second coupling piece (21) with a guide pin (23) in a guide slot (22) of the first coupling piece (21) engages to implement a rotation of the first coupling piece (20) in a translation of the second coupling piece (21) along the axis of rotation.

Dosing pump (1) according to one of claims 3 to 4, characterized in that the guide slot (22) is bounded on both sides, so that after a predetermined rotation of the output shaft (11), the rotation is transmitted to the metering pin (13). Dosing pump (1) according to one of claims 3 to 5, characterized in that the length of the guide slot (22) corresponds to about 25 to 50% of a full revolution about the axis of rotation.

Dosing pump (1) according to one of claims 3 to 6, characterized in that the slope of the guide slot (22) is selected such that the metering pin (13) is displaceable by 0.5 to 3 mm.

Dosing pump (1) according to one of the preceding claims, characterized in that the metering pin (13) has a tip which is shaped such that the outlet opening (16) by the metering pin (13) is positively closed.

Dosing pump (1) according to one of the preceding claims, characterized in that the dosing pin (13) has a sealing cap at its tip.

Dosing pump (1) according to one of the preceding claims, characterized in that the dosing head (13) has an integrated reservoir (17).

Dosing pump (1) according to one of claims 1 to 9, characterized in that the dosing head (13) has a feed opening for the liquid to be dispensed, which opens into the conveying passage (15).

Dosing pump (1) according to one of the preceding claims, characterized in that the dosing head (13) releasably with the coupling device (12) and a housing (2) of the metering pump (1) is connected.

13. dosing pump (1) according to one of the preceding claims, characterized in that it is a hand-held metering pump (1).