WO2002028614A1

WO2002028614A1 - Closure system

Info

Publication number: WO2002028614A1
Application number: PCT/CH2001/000605
Authority: WO
Inventors: Urs Fischer; Bruno Eng
Original assignee: Bruno Eng Mechanische Werkstatt
Priority date: 2000-10-04
Filing date: 2001-10-04
Publication date: 2002-04-11
Also published as: CH694723A5; AU2001291586A1

Abstract

The closure system for releasing and discharging, as desired, a flowable or sprayable material comprises a material passage, an outlet channel (7), and two closure pins (11) for closing the outlet channel (7). Said closure pins (11) are arranged radially symmetrical to one another and can each axially move inside a respective boring preferably provided at an angle to the flow-through direction. In the closed position, the nozzle channel (7) is closed by the closure pins (11) whose faces are resting against one another in a fluid-tight manner. The opening of the outlet channel (7) is effected by the force of pressure of the material pressing against the surfaces (21) of both pins (11). This force of pressure has to be greater than the force of the spring (19) acting counter thereto. If this is the case, both pins (11) inside the borings (12) are pressed outward at an angle, and the clamping ring (18) is pressed against the end section (2) whereby compressing the spring (19) and opening the outlet channel (7).

Description

Lock system

Technical field

DESCRIPTION

The invention relates to a novel closure system which can optionally be used as a spray nozzle, for example in plastics processing, as a metering and filling element for bulk goods, liquids, solutions and beverages, or as a spray nozzle for gases. The closure system according to the invention is therefore used wherever a flowable material, a solution, a liquid or a gas must be dispensed in a targeted or metered manner at low or high pressure.

A preferred application of the closure system according to the invention is plastic processing, in which spray nozzles are connected to a plasticizing cylinder, for example an extruder, and are used to inject the previously prepared, flowable plastic into a mold.

State of the art

Known spray nozzles for processing plastics, which are directly connected to an injection mold, are known, for example, from DE-A 37 445 19 and US Pat

EP-A 0 504 553 known. For example, EP-A 0 504 553 discloses a spray nozzle in which the mouth section of the nozzle channel is delimited by a rotationally symmetrical nozzle mouthpiece becomes. This nozzle mouthpiece can be pressed axially onto the nozzle body by means of a clamping ring. The contact pressure of the nozzle mouthpiece is generated with the help of at least one threaded element and the nozzle channel can be closed by a locking needle which is axially movable in a bore of the nozzle body arranged obliquely to the nozzle axis. The nozzle channel is tightly closed by a spherical head of the valve pin, which is guided into the outlet opening of the nozzle mouthpiece for this purpose.

When using known spray nozzles of this type, there is now a risk that the plasticized material will stick, dry, solidify and decompose in the vicinity of the nozzle outlet or on the sealing needle which at least partially projects into the nozzle channel even when fully open. This can adversely affect the properties of the spray nozzle, so that, for example, the machining pressure cannot easily be kept constant. In addition, the spray nozzle can even become completely blocked and these nozzles require regular maintenance and cleaning work by the operating personnel. In addition, it has been shown that the sealing needle protruding at least partially into the nozzle channel adversely affects the flow profile of the material passed through the nozzle during operation.

Injection molding devices for producing objects made of plastic are also known, in which the plasticized plastic reaches the mold cavity via an angled channel and a radially symmetrical nozzle immersed in a sprue opening of the injection mold. The extremely small nozzle connects the inflow channel drilled in a steel block to the mold cavity. In this case, the locking needle extends into the mouth opening of the nozzle in the closed position and thus limits the Mold cavity immediately. Today, plastics are increasingly being mixed with abrasive additives such as glass fibers, carbons and the like in order to open up further areas of application for molded parts, for example in mechanical engineering or in precision engineering. It is known that with this injection molding device, in the case of processing plastics with abrasive additives, problems with the tightness of the nozzle closure occur over time. This is especially the case if asymmetrical abrasions occur in the area of the mouth section of the nozzle channel serving as a seat and in the area of the free end of the valve pin, which impair the radial symmetry of this seat and this free end.

Outline of the invention

The invention is based on the object of creating a new type of closure system, but in particular a new type of spray nozzle for processing plastics, which does not have the disadvantages of the known nozzles. Starting in particular from the prior art known from EP-A 0 504 553, it should be made possible to avoid leaks occurring when using abrasive substance mixtures. Furthermore, it is to be avoided that the spraying of the flowable material is disturbed by material adhering to the nozzle, on the valve pin and / or at other exposed points and thereby for example impeding the spraying or the nozzle becoming blocked over time. In addition, the closure system should be designed in such a way that the formation of turbulence in the material flow through nozzle head parts protruding into the nozzle channel is avoided as far as possible.

According to the invention, this object is achieved by a closure system having the features of claim 1, namely by means of a closure system for selectively releasing and dispensing a flowable, sprayable or free-flowing material, with a material passage, an outlet channel and at least two closure needles for closing the outlet channel, the at least two radially opposite closure needles to the nozzle axis Include an acute angle, insert into the bores of the nozzle body that forms the outlet channel and flow symmetrically to one another, i.e. congruently, into the nozzle channel. The closure system according to the invention is essentially characterized in that the at least two closure needles can be inserted into the outlet channel to shut it off and can be fully extended to release the outlet channel, so that each closure needle on its side facing away from the outlet or nozzle channel End has a cut surface which is assigned to a sliding sleeve for controllably opening and closing the outlet channel and that each closure needle is additionally provided with a cut at its end section facing the outlet or nozzle channel with a chamfer which cuts off the jacket surface obliquely and merges into the end surface. which serves to effect the opening of the outlet or nozzle channel by the pressure of the flowable material hitting the needles.

Advantageous embodiments of the invention emerge from the dependent claims.

It is known from DE A 10 97 664 and DD A 64316 spray nozzles with two locking needles intended for closing the nozzle channel. However, for the subject matter of the present invention, these neither form the state of the art below nor provide a suggestion for solving the problem set according to the invention. Brief description of the drawing

The subject matter of the invention will now be described in more detail with reference to two exemplary embodiments. In the drawing shows

1 shows a closure system according to the invention designed as a spray nozzle, partly in section, partly in view, and with the nozzle opening released,

2 shows a view in the direction of arrow II of FIG. 1,

3 shows a section along the line III-III of FIG. 1,

4 shows the spray nozzle of FIG. 1 with the nozzle opening closed,

5 shows a view in the direction of arrow V of FIG. 4,

FIG. 6 shows the view of a locking needle in a state detached from the locking system,

Figure 7 is a view in the direction of arrow VII of Figure 6 and

8 shows a longitudinal section through a second closure system according to the invention with a closed nozzle opening.

Description of the preferred exemplary embodiments

The closure system, denoted as a whole in the drawing by 1, hereinafter also referred to as spray nozzle, is also used the end section 2 shown on the right in FIGS. 1 and 2 with a plasticizing cylinder, for example a screw extruder, detachably connected, for which purpose the end section 2 has a fastening element, such as a thread 3, a flange, a clamp or the like.

The spray nozzle 1 is generally rotationally symmetrical with respect to an axis 4 and has a nozzle body 5. This preferably consists entirely of a hard metal, for example steel, or stainless steel. Individual parts can, however, also consist of another material, for example ceramic or a plastic, within the scope of the invention.

The nozzle body 5, which is formed, for example, from two half-shells, has at its end on the left in FIGS. 1 and 2 a mouth section 6 with an optionally lockable or releasable nozzle channel 7 coaxial with the axis 4 and a central section connecting the mouth section 6 with the end section 2 8, wherein the mouth section 6 and the middle section 8 together form a cylindrical outer surface 9.

The central section 8 also has an inner surface section 10 which tapers away from the end section 2 in the direction of the nozzle channel 7 and which then tapers in the region of the mouth section 6 into the generally cylindrical nozzle channel 7. In the exemplary embodiment shown, the conical inner surface section 10 consists of a first section 10a, which is concave in axial section, for example spherical, and a narrower and conical second section 10b.

Two radially opposite locking needles 11 each form an acute angle with respect to the nozzle axis 4. They sit in bores 12 of the nozzle body 5, which in turn exactly 7 symmetrical to each other, i.e. congruent, in the nozzle channel.

The closure needles 11 are essentially cylindrical and have at one end a closure part 13 intended for closing the nozzle channel 7 and at their other end a guide section 14 serving to axially move the needle 11. The diameter of each needle 11 is at least as large as the diameter of the nozzle channel 7, but preferably larger than this.

The closure parts 13 of the two needles 11 are now cut obliquely in such a way that in the inserted state they form cutting surfaces 15 parallel to one another and to the axis 4, which lie close to one another in the closed state of the nozzle 1 and at a distance in the open state of the nozzle 1 stand from each other, which corresponds approximately or exactly to the diameter of the nozzle channel 7.

In contrast, the guide section 14 of each needle 11 has a vertical cut surface 16 in the inserted state and with a horizontal nozzle orientation and a vertical cut surface 17. Of these, the cut surface 16 abuts a sliding sleeve designed as a metallic clamping ring 18, which is plugged onto the middle section 8. The clamping ring 18 is pressed against the closure needles 11 by an annular spring 19 arranged between it and a radially outwardly projecting rib 20 of the central section 8.

The clamping ring 18 also overlaps the cut surface 17 of the guide section 14 with an annular projection 18a and forms with it a stop for the needles 11 belonging to the cut surface 17. According to the invention, each closure needle 11 is additionally provided at its front end section 13 with a cut 21 which obliquely cuts off the jacket surface and merges into the cut surface 15, which - as will be explained in more detail below - serves to open the nozzle channel by the pressure of the Needle 11 impinging spray material.

In the closed position, as shown in FIGS. 4 and 5, the nozzle channel 7 is shut off by the closing needles 11, which abut against one another in a fluid-tight manner, and the tips 13a of the two needles 11 protrude axially from the mouth section 6, for example. This position is achieved in particular by the spring 19 which, due to its spring force, presses the closure needles 11 into the nozzle channel 7.

The opening of the nozzle channel 7 is effected in the exemplary embodiment shown by the pressure force of the material striking the surfaces 21 of the two needles 11. This

Compressive force must be greater than the counteracting spring force. If this is the case, the two needles 11 are pressed obliquely outwards in the bores 12, and the clamping ring 18 is pressed against the end section 2, the spring 19 is pressed together and the nozzle channel 7 is released. As soon as the pressure force of the material acting on the needles 11 is again less than the spring force, the nozzle channel 7 closes, in which the needles 11 are reset to the closed position shown in FIGS. 1 and 2 by the action of the spring 19. It goes without saying that, depending on the material to be processed and in particular also on the compressive force of the material and the dimensioning of the gate surfaces 21, springs with different spring tensions are used. The spray nozzle 1 according to FIGS. 1 to 5 is a purely spring-actuated embodiment of the invention, which can be modified in various ways.

In the illustrated embodiment, the cut surface 16 of each valve pin 11 is arranged perpendicular to the axis 4. According to the invention, this surface can also be at an acute or obtuse angle to the axis 4 and / or to the cutting surface 17, so that there is the possibility of choosing the spring force acting on the needles 11 and thus also the pressure force required to open the nozzle channel to vary the special cutting surface geometry, in which case, of course, the clamping ring 18 has stops adapted to the cutting planes. A further possibility for setting the spring force acting on the needles 11 or the pressure force required to open the nozzle channel 7 over a wide range is to make the rib 12 acting as a spring base axially displaceable.

The material passage of the nozzle body 5 tapering toward the nozzle channel 7 and not described in more detail above can of course also be made somewhat slimmer than shown and / or additionally have at least one filter and / or mixing element.

Furthermore, the opening and closing of the nozzle channel can also be achieved with a control device instead of with a spring attached to the nozzle body, for which purpose hydraulic, pneumatic, mechanical or electromechanical control means are used. In this variant, the locking needles can be relieved of spring pressure that is constantly on them and the nozzle channel can be opened easily even at very low pressure. Figure 8 shows such a spray nozzle. The spray nozzle 101 according to FIG. 8 is essentially of the same design as the nozzle 1 described in detail with reference to FIGS. 1 to 7, that is to say it has a nozzle head 112 with a nozzle body 105 which is formed, for example, from two half-shells and is rotationally symmetrical with respect to the axis 104, and two are radial Opposing locking needles 111, which in turn flow exactly symmetrically to one another, that is to say congruently, into the nozzle channel.

In contrast to the nozzle 1, the spray nozzle 101 has none

Closure spring, but instead a control device with a sliding tube 120 acting on the sliding sleeve 118, a switching ring 121 and an adjusting ring 122. In combination, all these control means replace the function of the spring and allow the pressure-controlled opening and closing of the

Shower channel with, for example, hydraulic or pneumatic means.

There is also the possibility of providing more than two needles for closing the nozzle opening, for example three, four or six, which are then arranged symmetrically to one another and have matching cutting surfaces on their closure parts in such a way that they close the nozzle channel in a fluid-tight manner when the nozzle is closed to lock.

In addition, the wall parts of the nozzle body can additionally be provided with a heating and / or cooling device, not shown, for example with the heating means 123 according to FIG. 8 or with at least one heating cartridge inserted into an oblique bore. Finally, the nozzle body and / or the heating and / or cooling device can also be provided with thermal insulation if the intended operating modes require this. Finally, the closure system according to the invention, which is essentially characterized in that obliquely to the flow direction or perpendicularly to it, symmetrically arranged closure needles are provided, which can be inserted into the outlet channel (nozzle channel) to shut it off, can also be used anywhere there , where debris, liquids, solutions and drinks are to be filled in a dosed manner. In all of these cases, the closure system is not designed as a nozzle in the narrower sense and at most has no inner wall section tapering towards the outlet duct, as is the case with the above described exemplary embodiment is the case.

Claims

1. closure system for selectively releasing and dispensing a flowable, sprayable or free-flowing material, with a material passage, an outlet channel (7) and at least two closure needles (11, 111) for closing the outlet channel (7), the Include at least two radially opposite locking needles (11, 111) at an acute angle to the nozzle axis (4), insert them into bores (12) of the nozzle body (5, 105) forming the outlet channel (7) and symmetrically to each other, i.e. congruently mouth the nozzle channel (7), characterized in that the at least two locking needles (11, 111) can be pushed into the outlet channel (7) to shut it off and the outlet channel (7) can be fully extended to release the outlet channel (7) so that each locking needle (11, 111) 111) has at its end facing away from the outlet or nozzle channel (7) a cut surface (16) which has a sliding sleeve (18, 118) for controllably opening and closing the outlet channel ls (7) and that each closure needle (11, 111) at its end section (13) facing the outlet or nozzle channel (7) additionally has a cut (21) that cuts the jacket surface obliquely and opens into the end surface (15) ) is provided, which serves to open the outlet or nozzle channel (7) by the pressure of the

To achieve needles (11) of flowing material.

2. Closure system according to claim 1, characterized in that the diameter of each closure needle (11) is at least the same size as the diameter of the outlet channel (7).

3. Closure system according to one of claims 1 or 2, characterized in that the nozzle body (5) forming the nozzle channel (7) consists of two half-shells.

4. Closure system according to one of claims 1 to 3, characterized in that the sliding sleeve (18) arranged between it and a radially outwardly projecting rib (20) of the body (5), annular spring (19) to the Locking needles (11) can be pressed and that the locking needles (11) are held in the closed position due to the force of the spring (19).

5. Closure system according to one of claims 1 to 3, characterized in that an external control device with, for example, hydraulic, pneumatic, mechanical or electromechanical control means is provided for opening and closing the outlet or nozzle channel.

6. Closure system according to claim 5, characterized by a control device for pressure-controlled opening and closing of the nozzle channel with a sliding tube (120) acting on the sliding sleeve (118), a switching ring (121) and an adjusting ring (122).

7. Closure system according to one of claims 1 to 6, characterized in that three, four or six closure needles are provided for closing the outlet or nozzle channel, these being then arranged radially symmetrically to one another and fittingly to one another on their closure parts Cut surfaces have that, when closed, they close off the outlet or nozzle channel in a fluid-tight manner.

8. Closure system according to one of claims 1 to 7, characterized in that the wall parts still zu- are additionally provided with a heating and / or cooling device (123).

9. Closure system according to one of claims 1 to 8, characterized in that at least one filter and / or mixing element is arranged in the material passage.