Discharging device for the discharge of liquid media

Abstract

A discharging device for the discharge of liquid media is specified, with a pump chamber that comprises an inlet opening and an outlet opening, and with a piston that is displaceable in the pump chamber. The object is to be able to dispense a medium with high accuracy using the discharging device. For this purpose, the piston comprises a projection which enters the inlet opening after a predetermined stroke of the piston.

Claims

1. A discharging device for the discharge of liquid media contained in a tank, comprising: a pump chamber having an inlet opening and at least one outlet opening; a piston that is displaceable in the pump chamber, wherein the piston comprises a projection which enters the inlet opening after a predetermined stroke of the piston, wherein the at least one outlet opening is connected to a pressure-controlled outlet valve, and wherein, at an end of a discharge stroke of the piston, which includes the predetermined stroke, the piston connects the at least one outlet opening to a low-pressure region, which has a pressure equal to a pressure in the tank.

2. The discharging device according to claim 1, wherein the inlet opening is undersized as compared to a cross section of the projection.

3. The discharging device according to one of claim 1, wherein the inlet opening comprises a sealing lip that interacts with the projection.

4. The discharging device according to claim 1, wherein the piston comprises an enlargement region tapering in a direction away from the inlet opening, the enlargement region having a largest outer diameter configured to bear against an inner wall of the pump chamber, and wherein the enlargement region is movable so that, at the end of the discharge stroke, the enlargement region is positionable past at least a portion of the at least one outlet opening or to have entered a discharge chamber, which is connected to the at least one outlet opening, with a diameter larger than the largest outer diameter of the enlargement region.

5. The discharging device according to claim 1, further comprising a housing section, wherein the piston is guided in the housing section, and an air supply path is embodied between the piston and the housing section.

6. The discharging device according to claim 5, wherein the housing section forms a valve seat at an inner end of the air supply path, and wherein a valve element is embodied on or connected to the piston is arranged so that, in a non-actuated state of the piston, the valve element bears against the valve seat.

7. The discharging device according to claim 5, further comprising a filter arrangement positioned so that the air supply path passes through the filter arrangement.

8. The discharging device according to claim 5, further comprising a partition wall, wherein the air supply path is connected to at least one air supply opening, and the inlet opening is connected to an inlet channel, and wherein the partition wall is arranged to separate the at least one air supply opening, on a side facing away from the air supply path, from the inlet channel.

9. The discharging device according to claim 1, wherein the piston is movable in a movement direction oriented at an angle in the range of 60 to 120 relative to a dispensing direction for the medium.

10. A method for discharging liquid media from the discharging device according to claim 1, the method comprising: displacing the piston in the pump chamber, wherein, after a predetermined stroke of the piston, the projection of the piston enters the inlet opening.

11. The method according to claim 10, wherein, after a full discharge stroke of the piston, a predefined dose of the liquid media is dispensed through a nozzle, and wherein most of the full discharge stroke of the piston occurs after the projection enters the inlet opening.

12. The method according to claim 11, wherein, during the full discharge stroke following the projection entering the inlet opening, the method further comprises opening a pressure controlled outlet valve to supply the predefined dose to the nozzle.

13. The method according to claim 12, wherein, at an end of the full discharge stroke, connecting the at least one outlet opening to a low pressure region, whereby the pressure controlled outlet valve is closed.

14. The method according to claim 10, further comprising, after the projection enters the inlet opening, forming a seal between the inlet opening and the projection.

15. A method for discharging liquid media contained in a tank from a discharging device, the method comprising: inserting a projection of a piston into an inlet opening of a pump chamber of the discharging device after a predetermined stroke of the piston that is less than a full discharge stroke of the piston that discharges, via a pressure controlled outlet valve, a predefined dose of the liquid media through a nozzle of the discharging device, wherein at least one outlet opening of the pump chamber is connected to the pressure controlled outlet valve and at an end of the full discharge stroke of the piston, connecting the at least one outlet opening to a low-pressure region, which has a pressure equal to a pressure in the tank.

16. The method according to claim 15, wherein most of the full discharge stroke of the piston occurs after the inserting of the projection into the inlet opening.

17. The method according to claim 15, further comprising, after inserting the projection into the inlet opening, sealing the inlet opening against the projection.

18. The method according to claim 12, wherein the discharge device includes a pressure controlled outlet valve arranged to supply the liquid media to the nozzle, and the pump chamber comprises at least one outlet opening; and wherein, between the inserting of the projection and an end of the full discharge stroke of the piston, the pressure controlled outlet valve is opened to supply the liquid media to the nozzle.

19. The method according to claim 18, further comprising, after at the end of the full discharge stroke of the piston, the at least one outlet is connected to a low pressure region so that the pressure controlled valve is closed to stop the supply of the liquid media to the nozzle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

(2) FIG. 1 shows a schematic sectional view of a discharging device;

(3) FIG. 2 shows an enlarged partial view of the discharging device in the non-actuated state; and

(4) FIG. 3 shows an enlarged partial view of the discharging device in the actuated state.

DETAILED DESCRIPTION

(5) The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.

(6) FIG. 1 shows a discharging device 1 that is connected to a reservoir 2. The reservoir 2 can be filled with a liquid medium that is to be dispensed through a dispensing nozzle (or outlet opening) 3. For the sake of clarity, the medium is not illustrated.

(7) The discharging device 1 comprises a housing 4 that is snapped onto the reservoir 2 or attached to the reservoir 2 in another manner. A seal 5 is arranged between the housing 4 and the reservoir 2.

(8) In the housing 4, a pump housing 6 that encloses a pump chamber 7 is arranged. In the pump chamber 7, a piston 8 is arranged that can be actuated against the force of a spring 10 via a knob 9. During the actuation, the piston 8 is moved into the pump chamber 7 and thus reduces the volume of the pump chamber 7.

(9) The pump chamber 7 comprises an inlet opening 11 that is connected to an inlet channel 12. The inlet channel 12 produces a connection between the reservoir 2 and the inlet opening 11.

(10) Furthermore, as shown with more detail in FIG. 2, the pump chamber 7 comprises at least one outlet opening 13 which ends in an annular space 14 that is connected to an outlet channel 15. The outlet channel 15 then leads to a pressure-controlled outlet valve 16. The outlet valve 16 controls the dispensing of the medium through the outlet opening 3. Outlet valve 16 opens at a predetermined first pressure on its inlet side, that is, in the outlet channel 15, and closes at a predetermined second pressure in the outlet channel 15. The two pressures can be equal, but do not need to be.

(11) The piston 8 comprises a projection 17 which enters the inlet opening 11 shortly after the start of a movement in the direction of the inlet opening 11. A movement of the piston 8 out of its non-actuated or resting position illustrated in FIG. 2 is hereinafter referred to as a discharge stroke. The projection 17 of the piston 8 thus closes off the inlet opening 11 shortly after the start of the discharge stroke. At the start of the discharge stroke, however, a gap is present between the projection 17 and the inlet opening 11. The inlet opening 11 is somewhat smaller than the cross section of the projection 17, that is, the inlet opening 11 is undersized compared to the cross section of the projection 17. For this purpose, the inlet opening 11 is provided with a sealing lip 18. The sealing lip 18 bears against the projection 17 in a sealing manner during a movement of the projection 17 into the inlet opening 11. With the entry of the projection 17 into the inlet opening 11, there results a clearly defined closing-off of the inlet opening 11, and therefore a clearly defined moment at which a pumping of the medium located in the pump chamber 7 out through the outlet opening 13 begins during a further movement of the piston 8 into the pump chamber 7.

(12) Because the medium is normally incompressible, the corresponding pressure increase also occurs with the start of the pumping of the medium out of the pump chamber 7, which pressure increase leads to an opening of the outlet valve 16.

(13) The piston 8 comprises an enlargement region 19 which tapers in a direction away from the inlet opening 11. The enlargement region 19 can also be simply referred to as a cone, although a conical shape is not mandatory. The enlargement region 19 bears with the largest diameter 20 thereof against an inner wall 21 of the pump chamber 7. At the end of the discharge stroke (see FIG. 3), the largest diameter 20 enters a discharge chamber 22, which has a larger diameter than the pump chamber 7 and is connected to the outlet opening or the outlet openings 13. At this moment, the largest diameter 20 no longer bears against the inner wall of the pump chamber 7, as a result of which a connection is produced between the outlet opening 13 and a low-pressure region. Alternatively, the largest diameter 20 at least partially clears the outlet opening 13, that is, the enlargement region has been moved at least partially past the outlet opening 13. The outlet opening 13 is also connected to the low-pressure region in this manner. The pressure in the outlet channel 15 thus abruptly falls to the pressure in the low-pressure region. The outlet valve 16 closes. Because the closing pressure of the outlet valve 16, and thus the moment of closing, is also determined by the position of the piston 8 in the pump chamber 7, the volume of the medium dispensed through the outlet opening 3 can be dosed in a very exact manner.

(14) The low-pressure region comprises at least one air supply opening 23 in the pump chamber housing 6, which opening is connected to an air supply channel 24 in the housing 4. A pressure that is equal to the pressure in the interior of the tank 2 is thus present in the air supply channel 24 and in the air supply opening 23. This pressure is significantly lower than a pressure that is present in the pump chamber 7 during a discharge stroke of the piston 8.

(15) If the piston is moved back into its initial position or resting position under the influence of the spring 10 after completion of a discharge stroke, the projection 17 also moves out of the inlet opening 11. With the return movement of the piston 8, a negative pressure occurs in the pump chamber 7, so that medium from the reservoir 2 can enter the pump chamber 7 through the inlet channel 12 and the inlet opening 11 once a gap has formed again between the projection 17 and the sealing lip 18. In order to then produce a pressure compensation in the reservoir 2, an air supply path 25 is provided between the piston 8 and a housing section 26 in which the piston is positioned. The air supply path 25 is the only connection between the interior of the reservoir 2 and the surrounding environment.

(16) A filter arrangement 28 surrounds the piston 8. Accordingly, the air supply path 25 passes through the filter arrangement 28.

(17) At the end of the air supply path 25 that faces the inlet opening 11, the housing section 26 comprises a valve seat 27, against which a valve element that is embodied on the piston 8 or is connected to the piston 8 bears in a non-actuated state of the piston 8.

(18) In the present case, the valve element is formed by a region of the diameter enlargement 19 facing away from the inlet opening 11. Thus, in the non-actuated state of the piston 8, no more air enters the reservoir 2, so that the risk of a contamination of the contents of the reservoir 2 is minimized. Furthermore, the bearing of the diameter enlargement 19 against the valve seat 27 prevents liquid from being able to escape outside from the reservoir 2.

(19) The air supply opening or air supply openings 23 and the inlet channel 12 are separated from one another by a partition wall 29 on the side of the housing 4 facing the reservoir 2. Air that enters the discharging device 1 through the air supply path 25 therefore cannot mix with the liquid medium that is present in the inlet channel 12 and will shortly be suctioned into the pump chamber 7. A bubble-free filling of the pump chamber 7 can thus be achieved.

(20) A locking slider 30 is provided which can be slid under a bottom edge 31 of the knob 9 in order to prevent an actuation of the knob 9. The disabling of the knob 9 is reversible, however.

(21) Furthermore, the discharging device can comprise an outer sleeve 32 which secures a head 33 to the housing 4.

(22) The discharging device is in particular suitable for an upside down dispensing of the medium from the reservoir 2, that is, for a situation in which the reservoir 2 is arranged above the discharging device 1 in the direction of gravity.

(23) The piston 8 is arranged transversely to a dispensing direction for the medium and is movable, that is, the piston 8 forms an angle in the range of 60 to 120, preferably about 90, with a dispensing direction.

(24) It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.