JP2908506B2 - Apparatus for dispensing a defined amount of a flowable substance - Google Patents

Description

The present invention relates to an apparatus for dispensing a defined quantity of a flowable substance.

In this case, the concept of “fluid substance” is understood as a highly polymerizable material with fluidity, in particular a thermoplastic material. The thermoplastic resin material is a special adhesive, glue, or a similar material, such as a hot-melt adhesive, a filling material such as a sealant, or a lacquer.

(Problems to be solved by the prior art and the invention) Such a fluid substance is used in many applications.
Precisely defined quantities must be dispensed, but the usage is varied in several stages according to the plan. This is particularly problematic for relatively small quantities. For example, the amount of hot melt used is frequently changed between a few milligrams and 100 grams.

Heretofore, there has been no known dispensing apparatus capable of dispensing a substance over a wide area and dispensing a regulated amount with a small tolerance.

Such dosing devices need to be extremely inexpensive, to operate very accurately and to obtain accurately reproducible results.

The present invention achieves this object and, in particular, a device for dispensing a defined amount of a flowable substance which can be dispensed with very small tolerances and whose adjustable or weight can be grasped in a large range. Is to provide.

The present invention is directed to an apparatus for metering a defined amount of a flowable substance, especially a highly polymerized thermoplastic material,
A body connected to a material source of the flowable substance, the supply pipe being interruptable by a first valve, and a metering chamber connected to the supply pipe and having an outlet for the flowable substance; And a dispensing piston disposed in the dispensing chamber so as to be able to reciprocate by a precision drive device, whereby the object is achieved.

 The first valve is operable by air.

 The first valve is formed as a needle valve.

 The outlet is closable by a second valve.

 The second valve is operable by air.

 The second valve is formed as a needle valve.

The outlet is connected to a coating head via a connection pipe.

The precision drive is formed by an electric motor, in particular a stepping motor.

The precision drive is formed as a pneumatic drive.

The precision drive is formed as a hydraulic drive.

The first valve, the second valve and the precision drive are operable synchronously.

The metering piston is provided with a pair of stoppers for limiting the stroke.

 The body is provided with a heating element.

 A temperature sensor is disposed in the main body.

(Advantage) The advantage obtained by the present invention is based on constant volume dosing, that is, the flowable substance is always
Emitted in precisely defined quantities. Therefore, reproducibility is maintained according to the request.

By means of a simple constructional measure, that is to say an appropriate adjustment of the piston stroke, the volume of the dosing chamber, as well as the discharge of the fluid substance, can be very precisely adjusted.

For the defined reciprocating movement of the piston of the dosing chamber:
A precision drive is required. The precision drive is an electric motor, in particular a stepper motor, a pneumatic drive or a hydraulic drive, which operates with the required precision.

Once metered, the metering device usually has to discharge the same amount over a long period of time, so that even in such a case it can always be operated with a constant piston stroke.
In that case, in order to eliminate tolerances due to small precision drives, in a preferred embodiment, the position of the ends of the piston is limited by a suitable stopper,
A very accurate relationship.

These stops are adjustable, so that the piston stroke is adapted to different metering conditions.

Connect the outlet of the dosing chamber via a connecting pipe or connecting hose.
It is also possible to connect to a painting device. However,
As a result, the distribution is increased, and the variation in the allowable error may increase.

Thus, in a preferred embodiment, the outlet of the dosing chamber is opened and closed directly by a suitable valve. Thereby, the metering is
Adjusted very accurately.

Good results are obtained when a fluid substance is supplied under the pressure of the dosing chamber. Because, in this way, a complete filling of the entire metering chamber with the free-flowing substance is compensated. This also facilitates the supply of the flowable substance to the metering chamber, and thus makes it possible to achieve a high working frequency.

Since the volume of such a flowable substance depends on the temperature, in a preferred embodiment the body of the dosing chamber is heated and kept at a precisely defined temperature by means of a thermostat.

With such a dosing device, flowable substances, such as hot melts and sealants, are also very accurately and reproducibly metered, e.g. in quantities of the order of milligrams to about 100 grams required for molding. You.

Embodiments The present invention is described in detail by the following embodiments in connection with the attached schematic diagrams.

In FIG. 1, the apparatus of the present invention, generally indicated by the drawing symbol 10, compares the flowable substances, especially hot melts, sealants, glues, adhesives or similar highly polymerized thermoplastic materials. It is used for dispensing in a very small, fixed amount, that is, in a weight range of several milligrams to about 100 grams.

The dosing device 10 has a box-shaped main body 12 which can be maintained at a temperature determined by a heating elesont 38. For temperature control, a temperature sensor 36 is used, which, like the thermal element 38, is arranged in an opening formed in the main body 12.

Both the temperature sensor 36 and the thermal element 38 are connected to a regulating device (not shown).

On the left-hand side in FIG. 1, there is a connection for the supply of a fluid material, hereinafter referred to as a highly polymerized thermoplastic material.
A connection 28 is provided, which is connected to a source of material (not shown). This material source supplies the highly polymerized thermoplastic material under pressure in a most preferred manner.

The connection 28 communicates with a supply pipe 19 of the main body 12, which can be closed by a valve 14 having a needle valve 18.

The supply pipe 19 is connected to another supply pipe 30 extending parallel to the supply pipe 19 via a locking portion that can be closed by the needle valve 18. The supply pipe 30 is connected to the supply pipe 30.
To the first part 32 of the dosing chamber extending at right angles to This first part 32 is connected to a second part 34 of the dosing chamber, and the second part 34 of the dosing chamber is arranged in line with the Extending in the direction.

According to the configuration of FIG. 1, the lower part of the first part 32 of the dosing chamber is closed by a plate 26,
For example, there is an outlet 28 configured as a nozzle.

The plate of the first part 32 in the dosing chambers 32 and 34
On the opposite side of 26 is provided another valve 20, the needle valve 24 of which opens and closes an outlet 28.

The two valves 14 and 20 are in two positions, indicated by symbols 16 and 22, respectively, and are pneumatically operable by two air flows.

According to the configuration of FIG. 1, in a second part 34 extending laterally of the metering chambers 32 and 34, a piston 42 can reciprocate, and the peripheral surface of the distal end of the piston 42 is connected to the metering chamber 32. and
It is in contact with the inner wall of the second part 34 at 34. piston
The distal end of 42 is provided with three ring-shaped grooves extending in the circumferential direction, and fitted with O-rings 44 made of an elastically deformable material. Each O-ring 44
Seals the tip of the piston 42 against the inner wall of the second part 34 in the metering chambers 32 and 34.

The piston 42 has a flange 43,
43 is in contact with the right wall of the body 12 in the position shown in FIG. 1, so that the flange 43 is used as a stop for the stroke of the piston 42 to the left.

On the shaft 46 is an intermediate member 48, which is used as a stop for the piston stroke to the right. Thus, according to the configuration of the embodiment shown in FIG. 1, the stroke of the piston 42 corresponds to the section between the right face of the intermediate member 48 and the left face of the transmission 50. The transmission 50 controls the rotational movement of a stepping motor 54, usually an electric motor, by the reciprocating movement of a shaft 46 and the second part of the metering chambers 32 and 34.
This translates into a reciprocating motion of the piston 42 at 34.

The stepping motor 54 has a hollow shaft 55 that houses the right end of the shaft 46, and the transmission 50 produces a piston stroke by rotation of the hollow shaft 55.

The main body 12 is fixed to one side of the common substrate 40, and a stepping motor 54 as an electric motor is fixed to the other side of the common substrate 40.

During operation of the dosing device 10, first, the piston 42 is moved to the right end position by the stepping motor 54. At this time, the valve 20 is connected to the metering chamber 32 by the needle 24.
And the outlet 28 of the first part 32 at 34 is closed. Further, the needle valve 18 of the valve 14 opens the supply pipes 19 and 30.

In such a state, a source of a liquid, highly polymerized thermoplastic material, not shown, supplies this material via the connection 28, the supply pipes 19 and 30, and the first portions 32 in the metering chambers 32 and 34. Then, the supply pipe 30 and the metering chambers 32 and 34 are completely filled with this material.

The valve 14 is then closed, and the supply pipes 19 and 30 are shut off accordingly. Alternatively, metering can be performed when valve 14 is open. However, in this case, it is provided that the highly polymerized thermoplastic material is supplied under pressure. It is better to close year 14 especially if very precise dosing is required.

At this point, the highly polymerized thermoplastic material is in a precisely defined volume, with a volume limited by the location of the valve 14, outlet 28, and distal end surface of the piston 42. This capacity is accurately determined.

Next, valve 20 is opened, thereby opening outlet 28, and simultaneously or with a predetermined time delay, piston 42 is moved to the left in FIG. Therefore,
The amount of flowable substance determined exactly on request is
Emitted from 28.

The valve 20 is closed again as soon as the piston 42 has reached the end position as understood from FIG. 1, i.e. as soon as the stopper 43 contacts the right wall of the body 12.

In this case, the amount of fluidized, highly polymerized thermoplastic material discharged depends only on the corresponding stroke of the piston 42. Therefore, the amount is determined very accurately.

After this amount of fluid has been expelled, the piston 42 is again moved to the right by the stepping motor 54 so that the evacuation process can be started again.

To change the amount of flowable material discharged, the angle of rotation of the stepper motor 54 only has to be adjusted to meet the requirements. In this case, piston 42
The corresponding adjustment of the mechanical stoppers 43, 48 is assisted.

FIG. 2 shows a modification of the arrangement device 10 according to FIG. 1, in which the stepping motor 54 as motor in FIG. 1 is replaced by a pneumatic drive 56, a so-called "pneumatic engine". The drive 56 is operated by two arrows, a flow of compressed air and a flow of suction air, indicated by the symbol 58.

Other configurations of this embodiment are the same as those of the embodiment shown in FIG. 1 and have the same functions, so that detailed description is omitted.

FIG. 3 shows a further modification of the dispensing device 10, in which a stepping motor 54 as an electric motor in FIG. for that reason,
The reciprocating movement of the piston 42 and the shaft 46 is performed by a demand-controlled liquid flow. The circuit for this flow has a general configuration. Therefore, a detailed description will not be necessary.

FIG. 4 shows a variant corresponding to the metering device 10 of the embodiment according to FIG. 1, in which a general coating head 64 is connected to the outlet 28 via a tube 62.

The painting head 64 therefore comprises another outlet 66, which can be opened and closed by a valve 68.

The needle valve 24 of the valve 20 and the needle valve of the valve 68 are opened and closed synchronously so that the flowable highly polymerized thermoplastic material passes from the outlet 28 via the tube 26 and the painting head 64 to the outlet 66. , Is discharged from there.

In the embodiment of FIG. 4, the valve 20 having the needle valve 24 may not be provided as required. Therefore, the required control is performed only via the valve 68.

As can be seen in FIGS. 1 to 4, the supply pipe 30 is closed by a stopper 31. Alternatively, the supply tube 30 may be reconnected to a source of highly polymerized thermoplastic material to simultaneously serve as a return tube. At that time, it is also possible in some cases to provide another shut-off valve, which is operated synchronously with the other two valves 14 and 20.

(Effect of the Invention) As described above, the dispensing device of the present invention is capable of dispensing a predetermined amount of a substance having fluidity with an extremely small tolerance despite its simple configuration. Therefore, the required quantity can be metered very reproducibly.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of a dispensing device, FIG. 2 is a sectional view of a second embodiment of the dispensing device, and FIG. 3 is a third embodiment of the dispensing device. FIG. 4 is a sectional view showing a modification of the first embodiment shown in FIG. 10 ... metering device, 12 ... body, 14 ... valve, 18 ... needle valve, 19
... supply pipe, 20 ... valve, 26 ... plate, 28 ... outlet, 30 ... supply pipe, 32 ... first part of the metering chamber, 34 ... second part of the metering chamber,
36 ... temperature sensor, 38 ... thermal element, 42 ... piston, 43
... Flange, 44 ... O-ring, 48 ... Intermediate member, 50 ... Transmission device, 54 ... Stepping motor, 56 ... Pneumatic drive device,
60 ... Liquid drive, 64 ... Painting head, 66 ... Outlet, 68 ...
valve.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B05C 5/00 B05C 11/10 F04B 13/00

Claims (13)

(57) [Claims] An apparatus for dispensing a defined amount of a flowable substance, in particular a highly polymerized thermoplastic material, the apparatus being connected to a source of the flowable substance. A supply pipe which can be shut off by one valve, a body connected to the supply pipe and having a metering chamber having an outlet for a flowable substance; and a reciprocating movement of the metering chamber by a precision drive. An apparatus for dispensing a defined amount of a flowable substance having a dispensing piston disposed and a thermal element disposed on a body. 2. The apparatus of claim 1 wherein said first valve is operable by air. 3. The device according to claim 1, wherein the first valve is formed as a needle valve. 4. Apparatus according to claim 1, wherein said outlet is closable by a second valve. 5. The apparatus according to claim 4, wherein said second valve is operable by air. 6. Device according to claim 4, wherein the second valve is formed as a needle valve. 7. The apparatus according to claim 1, wherein the outlet is connected to a coating head via a connecting pipe. 8. Apparatus according to claim 1, wherein said precision drive is formed by an electric motor, in particular a stepper motor. 9. The device according to claim 1, wherein the precision drive is formed as a pneumatic drive. 10. The device according to claim 1, wherein the precision drive is formed as a hydraulic drive. 11. Apparatus according to claim 1, wherein the first valve, the second valve and the precision drive are operable synchronously. 12. The metering piston is provided with a pair of stoppers for limiting a stroke.
An apparatus according to any one of the above. 13. The apparatus according to claim 1, wherein a temperature sensor is disposed in said main body.