A method and dosaging device for delivering a liquid

Abstract

 The invention relates to a method for delivering a liquid from a chamber via a passage which can be closed by a closing means. When said passage is being opened, the fluid is set in motion by vibrating the fluid present in the chamber. The method can be performed by a dosaging device for delivering a fluid, said dosaging device being provided with a chamber having a passage which can be closed by means of a closing means. Further there are provided by means by way of which parts of the device being in contact with fluid present in the chamber can be set into vibration.

Description

[0001] The invention relates to a method for delivering a liquid from a chamber via a passage which can be closed by a closing means.

[0002] The delivery in a desired quantity or the dosing of a liquid via a closable passage is largely determined by the reologic behaviour or flowing behaviour of the liquid. Said reologic behaviour of the liquid is influenced by the viscosity, the thixotrophy and the flowing point of the liquid. Said three properties determine the so-called "shortness" of a liquid, i.e. the time it takes to put a liquid from a flowing condition into a stationary condition.

[0003] In particular with said so-called "short" liquids problems occur in circulation dosaging systems, when the diameter of the closable paasage is small. The resistance in the passage may be so great that, in spite of the liquid in the chamber being under a certain pressure, no liquid will flow from the chamber via the passage when the passage has been released by the closing means.

[0004] The object of the invention is to obtain a method wherein said problem can be easily overcome.

[0005] According to the invention this can be accomplished in that, when the passage is being opened, the liquid is set in motion by vibrating the liquid present in the chamber.

[0006] In practice it has become apparent that vibrating the liquid in this manner sets the liquid in motion in such a manner that the liquid will flow out of the passage in the intended manner.

[0007] A further aspect of the invention relates to a dosaging device for delivering a liquid, said dosaging device in particular being suitable for carrying out a method according to the invention, whereby said dosaging device is provided with a chamber having a passage which can be closed by means of a closing means, means being provided according to the invention by way of which parts of the device being in contact with liquid present in the chamber can be set into vibration.

[0008] When such a dosaging device is being used the liquid can be set in motion in a simple manner when the closing means is opened, such that the liquid will flow out of the passage in a regular manner as soon as the passage has been opened by the closing means.

[0009] The invention will be explained in more detail hereinafter with reference to the accompanying Figures, which diagrammatically illustrate an embodiment of the construction according to the invention.

Figure 1 diagrammatically illustrates an installation for delivering a liquid.

Figure 2 shows a dosaging device forming part of the installation according to Figure 1, partly in section and partly in elevational view.

[0010] The installation illustrated in Figure 1 is in particular intended for delivering so-called short liquids, such as e.g. dye used in the printing industry, in a dosed manner.

[0011] The installation comprises a vessel 1 containing the liquid to be dosed. A suction pipe 2 extends into said vessel, which is connected to a pump 3. In the suction pipe there is accommodated a stop valve 4. The pump 3 can be driven in a usual manner by means of a motor 3′.

[0012] The delivery side of the pump 3 is connected to a dosaging device 6 via a pressure pipe 5.

[0013] In the pressure pipe 5 there is accommodated a filter 7, as well as a retaining valve 8, which prevents a reflux of the liquid from the dosaging device to the pump.

[0014] Upstream and downstream of the filter 7 a bypass 9 is connected to the pressure pipe 5, in which bypass there is accommodated a check valve 10. Said check valve 10 will open when for some reason the filter does not pass any liquid, e.g. when the filter 7 has become clogged.

[0015] As is illustrated in more detail in Figure 2 the pressure pipe 5 opens into a chamber 11, which is recessed in a casing 12 forming part of the dosaging device. To said chamber 11 there is furthermore connected a discharge pipe 13. As is illustrated in Figure 1 the end of the discharge pipe 13 remote from the dosaging device 6 opens into the vessel 1 via a constriction 14. In the return line 13 there is furthermore provided a check valve 15. The constriction 14, in combination with the yield of the pump, takes care of it that a certain pressure is built up and maintained in the pipes 5 and 13 during operation. The valve 15 prevents that the pipe 13 empties when the vessel 1 is being exchanged.

[0016] As is furthermore apparent from Figure 2 a pair of dosaging nipples 16 and 17 is provided in a wall of the casing 12. The diameter of the bore 18 in the nipple 16 is comparatively large and can be closed by means of a valve disc 19, which is secured to the end of a valve stem 20.

[0017] The end of the valve stem 20 projecting from the casing 12 is surrounded by a compression spring 21, which is retained by a valve disc 22 fixed to the valve stem and a support plate 23 supporting the casing 12, all this in such a manner that the spring 21 attempts to keep the valve disc 19 in a position closing the nipple 16 as illustrated in Figure 2.

[0018] The end of the valve stem 20 remote from the valve disc 19 is coupled, by means of a head piece 24, to a sliding piece 25, which is in turn coupled to the piston rod 26 of a setting cylinder 27. By moving the sliding piece 25 by means of the setting cylinder 27 to the right, when seen in Figure 2, the valve disc 19 will likewise be moved to the right, and thus effect an open communication between the passage 18, through the nipple 16, and the chamber 11.

[0019] The diameter of the stepped passage 28 provided in the nipple 17 is considerably smaller than the diameter of the passage 18 provided in the nipple 16.

[0020] The nipple 17 cooperates with a plunger 29, whose boundary plane directed towards the nipple 17 cooperates with a collar 30 of the nipple forming a seat. A pin 31 being integral with the plunger joins up with the end of the plunger, said pin fitting the stepped bore 28, as is illustrated in Figure 2.

[0021] The plunger 29 is surrounded by a compression spring 32 in a similar manner as the piston rod 20, which compression spring attempts to keep the plunger 29 in the position illustrated in Figure 2, in which position the passage 28 through the nipple 17 is closed by means of the plunger 29.

[0022] The plunger 29 is furthermore connected to a sliding piece 34 by means of a head piece 33.

[0023] The end of the sliding piece 34 remote from the head piece 33 is connected to one end of a vibrating device 35. The other end of the vibrating device is coupled, by means of a connecting bracket 36 and a buffer 37, to a pair of setting cylinders 38 and 39 connected one behind the other. The construction is thereby such that by only operating the setting cylinder 38 the plunger 29 is moved to the right, when seen in Figure 2, along such a distance that part of the length of the pin 31 being integral with the plunger 29 is still inserted in the passage 28 provided in the nipple 17, so that in this position liquid can only flow out of the chamber 11, via the passage 28, by way of the clearance space between the pin 31 and the bore 28.

[0024] When both setting cylinders 38 and 39 are operated the plunger 29 will be moved to the right, when seen in Figure 2, along such a distance that also the pin 31 is entirely retracted from the passage 28.

[0025] The operation of the installation described above is as follows. During operation the pump 3 will be put into operation, so that said pump draws liquid, e.g. dye, from the vessel 1 and supplies said liquid to the chamber 11 in the casing 12 of the dosaging device 6. From said chamber the liquid can return to the vessel 1 via the return line 13. It will be apparent that as a result of the presence of the retaining valve 15 and the constriction 14 a certain pressure will be constantly maintained in the chamber 11.

[0026] When liquid is to be delivered by means of the dosaging device the passage 18 in the nipple 16 can be released by moving the piston rod 20 and the valve 19 fixed thereto to the right, when seen in Figure 2, by means of the setting cylinder 27. The diameter of the passage 18 is thereby such that also so-called short liquids can flow out of said passage without any problems, under the influence of the pressure present in the chamber 11.

[0027] For a more accurate dosaging, e.g. when a large quantity of liquid has been discharged via the nipple 16 and a more accurate regulation of the discharge of the liquid must be effected when the desired quantity is substantially reached than is possible by means of the nipple 16, the passage 18 in the nipple 16 can be closed again by means of the valve disc 19, whilst the passage in the nipple 17 is being released. The procedure will usually be such that first the pin 31 secured to the plunger 29 is retracted from the passage 28, in order to partially move back into the passage 28 again during the last discharging stage, so that the discharge is then determined by the clearance passage between the pin 31 and the part of the hole 38 having the smallest diameter.

[0028] In particular the clearance passage between the wall of the hole 28 and the outer circumference of the pin 31 is so small that especially when a so-called short liquid is processed no liquid will flow out of the open passage. This disadvantage of known devices can now be overcome in a simple manner by setting the plunger 29 into vibration along its longitudinal axis by means of the vibrating device 35. Said vibrating motion of the plunger will also be transmitted to the liquid, as a result of which said liquid will be set in motion and appears to exit from the nipple 17 in a regular manner.

[0029] Of course it will also be conceivable to set the liquid in the chamber 11 in motion in another manner, e.g. by providing a vibrating device on the casing 12 or the like. Setting in motion the means formed by the plunger 29 and closing the passage 28 of the nipple appears to be very effective, however, since said means is located in the immediate vicinity of, or even partially in, the passage for the discharge of the liquid.

Claims

1. A method for delivering a liquid from a chamber via a passage which can be closed by a closing means, characterized in that, when said passage is being opened, the liquid is set in motion by vibrating the liquid present in the chamber.

2. A method according to claim 1, characterized in that a means is vibrated, by way of which said passage can be opened and closed.

3. A dosaging device for delivering a liquid, said dosaging device being provided with a chamber having a passage which can be closed by means of a closing means, characterized in that means are provided by way of which parts of the device being in contact with liquid present in the chamber can be set into vibration.

4. A dosaging device according to claim 3, characterized in that said vibrating means are connected to said closing means.

5. A dosaging device according to claim 3 or 4, characterized in that said closing means is formed by a plunger, which is movable in its longitudinal direction for opening and closing said passage, and which can be set into a vibrating motion by said vibrating means.

6. A dosaging device according to claim 5, characterized in that a vibrating device is provided between the plunger and a setting cylinder, by means of which the plunger is adjustable in its longitudinal direction.

7. A dosaging device according to claim 5 or 6, characterized in that said plunger is at one end provided with a pin which fits said passage.

8. A dosaging device according to claim 7, characterized in that said plunger is adjustable from the position closing said passage into a first positon, in which said pin still partially extends into the passage, and a second position, in which said pin is entirely retracted from said passage.

9. A dosaging device according to claim 8, characterized in that said plunger is steplessly adjustable from the position in which said passage is closed into a position in which said pin is still partially located inside said passage.

10. A dosaging device according to any one of the preceding claims 3 - 9, characterized in that a supply line and a discharge line are connected to the chamber of said dosaging device, whilst a pump is incorporated in said supply line, by means of which a liquid can be continuously supplied to said chamber.

Drawing