JP2006218450A - Spray gun - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spray gun in which a liquid is circulated to be supplied and is switched to be sprayed by a quick switching action. <P>SOLUTION: A liquid supply port 7 and a liquid return port 8 are formed respectively at a position shifted in the moving direction of a needle valve 5 for opening and closing a liquid spray port 4, a valve mechanism 47 is provided in the middle of a flow passage through which the liquid supply port 7 and the liquid return port 8 are communicated with each other and the flow of the liquid supplied from the liquid supply port 7 is switched to the liquid return port 8 side or the liquid spray port 4 side by the movement of the needle valve. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a spray gun that ejects a liquid from a nozzle and sprays the liquid by mixing air at the same time as the ejection to form a film on a coating or a solid pharmaceutical preparation.

From the viewpoint of supplying liquid to a spray gun that forms a coating on a solid preparation for coating or pharmaceutical use, and providing liquid instantaneously and preventing the liquid from separating in the piping path when the liquid is a mixed liquid, There has been a coating system in which liquid is circulated and liquid is sprayed from a spray nozzle of a spray gun when necessary (Patent Document 1).
JP 2002-159907 A

  However, in Patent Document 1, the liquid is circulated through the spray gun to switch from the spray stop state to the spray state and from the spray state to the spray stop state, but the liquid switching valve mechanism is a spray gun. Since it is provided in a separate place, it is inevitable that the liquid stays in the liquid circulation pipe. Therefore, when the liquid is a mixed liquid, the liquid is separated, and the spray state required at the start of spraying may not be provided.

  An object of the present invention is to provide a spray gun that circulates the supply of liquid and switches to spraying of liquid by an agile switching operation.

  In view of the above problems, a spray gun according to the present invention includes a liquid supply port that supplies liquid, a liquid spray port that sprays liquid using a needle valve, and a liquid return port that returns liquid when the liquid spray port is closed. The needle valve prevents liquid from flowing to the liquid return port when the needle valve opens the liquid spray port in the passage between the liquid supply port and the liquid return port. A valve mechanism for flowing liquid to the liquid return port when the spray port is closed is provided.

  This eliminates the need to provide an external valve since the switching valve is provided inside the spray gun.

  Further, the valve mechanism is formed by an end face formed in the needle valve and a seal member provided in the passage, and the seal member can be reliably opened and closed by the movement of the needle valve.

  Since the spray gun of the present invention has a built-in valve mechanism, the spray gun can be instantaneously switched to enter the spray state and the circulation state, and the switching time lag is eliminated. Furthermore, by incorporating a valve mechanism in the spray gun, the entire system including the spray gun can be simplified and the cost can be reduced.

  Further, since the liquid is constantly circulated or sprayed, it does not stay in the piping path, and when the mixed liquid is sprayed, the liquid is not separated even when the spray is stopped.

  Embodiment 1 of the present invention will be described below with reference to the drawings.

    1, 2, 3, and 4 show an embodiment of the present invention, and FIG. 1 is a cross-sectional view showing a state in which a liquid spray port of a spray gun is opened. FIG. 2 is a cross-sectional view showing a state where the liquid spray port of the spray gun is closed. FIG. 3 is an exploded perspective view of the main part. FIG. 4 is a perspective view showing the piping state of liquid and air to the spray gun.

  In the figure, a spray gun 1 is provided over the spraying part 3 disposed on the front end side (left side in FIG. 1) of the body part 2 and from the front end side to the rear end side of the body part 2. A needle valve 5 for opening and closing the mouth 4, a needle opening and closing mechanism 6 disposed on the rear end side (right side in FIG. 1) of the body portion 2, and a liquid supply port for supplying liquid to the spraying portion formed in the body portion 2 7, a liquid return port 8 for liquid, a needle valve operating air supply port 9a for supplying air to the spray unit 3 and the needle opening / closing mechanism 6 formed in the body 2, an atomizing air supply port 9b, and pattern air It is comprised from the supply port 9c (refer FIGS. 1-4).

  The positions of the liquid supply port 7, the liquid return port 8, the needle valve operating air supply port 9a, the atomizing air supply port 9b, and the pattern air supply port 9c provided in the body 2 are shown in FIG. 1, FIG. 2, and FIG. In order to facilitate explanation, the liquid return port 8, the needle valve operating air supply port 9a, the atomizing air supply port 9b, and the pattern air supply port 9c are linearly arranged in the moving direction of the needle valve 5. However, the liquid supply port 7 and the liquid return port 8 are provided in the vertical direction in the figure, and the needle valve operating air supply port 9a, the atomizing air supply port 9b, and the pattern air supply port 9c are angled with respect to both the ports 7 and 8. It is easier to install the piping. These positions can be determined according to the design.

  Although the trunk | drum 2 is cylindrical, the internal diameter is not formed with the same diameter altogether, but is formed from at least 3 diameters. The body 2 has a relatively large diameter for forming a liquid chamber 10 (left side in FIGS. 1 and 2) on the front end side and a piston chamber 11 (right side in FIGS. 1 and 2) on the rear end side, and a piston chamber. 11 and a passage 13 for accommodating a seal mechanism 12 extending from the liquid chamber 10 to the liquid chamber 10 side. The piston chamber 11 is connected to a needle valve operating air supply port 9a formed in the body 2 by a passage 9d.

  The seal mechanism 12 includes annular spacers 15 and 16 that contact the inner wall of the passage 13, seals 18 and 19 provided on the inner surfaces of the spacers 15 and 16, and a presser 17 that attaches a seal portion to the spacer 16.

  The liquid supply port 7 and the liquid return port 8 are formed at right angles to the axial direction of the body portion 2 and are arranged so as to be shifted forward and backward (the front indicates the left side in FIGS. 1 to 3). The liquid supply port 7 is disposed close to the spray unit 3 side and communicates with the liquid chamber 10. The liquid return port 8 is disposed close to the needle opening / closing mechanism 6 side and communicates with the spray portion 3 side of the seal mechanism 12 through the passage 13.

  The spray unit 3 includes a nozzle 20 for spraying liquid and an air cap 21 that injects air to the liquid ejected from the nozzle 20. In order to arrange the air cap 21 at the tip of the body portion 2, the air cap 21 is fastened and fixed by a ring 23 that is screwed into a screw portion 22 formed on the outer periphery of the body portion 2.

  A packing housing 26 made of a fluororesin having a groove 25 on the tip side is provided in the liquid chamber 10 of the body 2 after a packing 24 made of fluororesin is provided on the back side (right side in FIG. 1) of the liquid chamber 10. Provided. Holes 29 and 30 having the same diameter as the liquid chamber 10 are formed in the central shaft portions of the packing 24 and the packing housing 26 so that the needle valve 5 can pass therethrough.

  In the groove 25 of the packing housing 26, the outer periphery of the nozzle 20 with the liquid seal packing 27 is screwed.

  As shown in FIG. 1, the air cap 21 has a step portion 28 formed on the outer periphery. The flange 14 of the ring 23 is in contact with the step portion 28 and is in close contact with the body portion 2.

  The nozzle 20 has a frustoconical outer periphery near the tip, a liquid spray port 4 at the center of the tip, and a valve seat 31 inside the liquid spray port 4. Further, a flange 32 extending outward from the end of the frustoconical shape of the nozzle 20 is formed.

  The liquid seal packing 27 is provided on the inner surface of the nozzle 20, and the tip 5 a of the needle valve 5 is provided in an opening 27 a of the liquid seal packing 27 that is continuous with the liquid spray port 4 so as to freely advance and retract.

  The air cap 21 has a front protrusion 33 symmetrically at the front end of the nozzle 20 with a vertical plane including an axis as a plane of symmetry. The forward projecting portion 33 is provided with an air passage 34 extending in the front-rear direction (left-right direction in FIG. 1) and an obliquely inward air hole 36 communicating with the front end of the air passage 35.

  The air passages 34 and 35 are connected by an annular passage on the body 2 side, and are connected by a pattern air supply port 9 c and a passage 9 f formed in the body 2. The direction of the air hole 36 is determined so that the air blown from the air hole 36 is blown to a spray flow formed by an air hole 39 and a liquid spraying port 4 which will be described later. Pattern).

  A large number of air holes 37 are arranged on the circumference of the flange 32 of the nozzle 20. The air hole 37 communicates with a space 38 formed between the air cap 21 and the flange 32, and the air hole 37 is connected by an atomizing air supply port 9b and a passage 9e to guide air.

  An air hole 39 is formed at the center of the air cap 21. The tip of the nozzle 20 is located in the air hole 39, and the air blown out from the air hole 39 forms so-called atomized air. That is, the air from the air hole 39 sucks out the liquid led out from the tip of the nozzle 20 with a negative pressure and atomizes it to form a spray flow.

  The air cap 21 has an auxiliary air hole 40 formed at a cross-shaped position around the air hole 39. The auxiliary air holes 40 prevent liquid droplets from adhering to the front surface of the air cap 21, and the air blown from the auxiliary air holes 40 and the air holes 36 adjusts the liquid spray shape (spray pattern). is doing.

  The needle opening / closing mechanism 6 is attached to the end of the needle valve 5 with a seal member 41 and a washer 42 sandwiched between caps 43 and 44 for sealing against the inner wall of the piston chamber 11.

  One end of the spring 45 is in contact with the washer 42. On the opposite side of the spring 45, a support ring 46 that is in contact with the other end of the spring 45 is hinged to the outer periphery of the body portion 2. The spring 45 moves the needle valve 5 in a direction to close the liquid spray port 4 of the nozzle 20 by the force of the spring 45 when air is not introduced into the piston chamber 11 from the needle valve operating air supply port 9a (see FIG. 2 state).

  The body portion 2 is provided with a valve mechanism 47 that switches the flow of the liquid between the spray portion 3 side and the liquid return port 8 side. The valve mechanism 47 is provided in the passage 13 between the liquid supply port 7 and the liquid return port 8.

  The needle valve 5 has a narrow diameter portion 48 at a position across the passage 13 and the liquid chamber 10. The passage 13 has an annular seal member 50 having a hole 49 having a diameter larger than the small diameter portion 48 smaller than the diameter of the needle valve 5 from the piston chamber 11 side, and a hollow opening diameter of the liquid return port 8. The ring 52 having the same hole 51, the annular seal member 53, the seal 18, the spacer 15, the spacer 16, the seal 19, and the presser 17 are attached in this order.

  The hole 49 of the annular seal member 50 is sealed by contact with the end face of the small diameter portion 48 of the needle valve 5 and switches the flow of the liquid. That is, when air is supplied to the piston chamber 11, the needle valve 5 moves from the state shown in FIG. 2 to the right side in the drawing to be in the state shown in FIG. At this time, the end surface 48a on the spraying portion side of the small diameter portion 48 comes into contact with the peripheral edge of the hole 49 to block the liquid flow. At the same time, the tip 5 a of the needle valve 5 is separated from the opening 27 a to open the liquid spray port 4, and the liquid flow flows to the liquid supply port 7 and the liquid chamber 10.

  Further, when the air to the piston chamber 11 is stopped, the needle valve 5 moves from the state of FIG. 1 to the left side in the drawing to be in the state of FIG. At this time, the end surface 48 a on the spraying portion side of the small diameter portion 48 is separated from the peripheral edge of the hole 49 and opens the hole 49. At the same time, the tip 5 a of the needle valve 5 enters the opening 27 a and closes the opening 27 a, so that the liquid flow flows to the liquid return port 8.

  Since the valve mechanism 47 is for switching the flow of the liquid flowing in from the liquid supply port 7 to the spray unit 3 side and the liquid return port 8 side, in the liquid chamber 10 sandwiching the liquid supply port 7, that is, Even if a valve is provided on the spray unit 3 side, the flow of the liquid can be switched.

  The liquid supply port 7 is connected to a liquid tank 54 through a liquid flow meter 55 and a pump P through a pipe 56. Further, the liquid return port 8 returns the liquid to the liquid tank 54 through the pipe 57 and constitutes a circulation path.

  The needle valve operating air supply port 9a is connected to the compressor C through a pressure adjustment valve 59 and a valve V1 through a pipe 58, and the pattern air supply port 9c is connected through a pressure adjustment valve 61 and a valve V2 through a pipe 60. The atomized air supply port 9b is connected to the compressor C via a pressure regulating valve 63 and a valve V3 through a pipe 62.

  In such a case, the spraying operation will be described.

  Spray stop state

  In the spray stop state, the valve V1 is closed and air is not supplied to the piston chamber 11, and the valves V2 and V3 are closed and air is not supplied to the air passages 34 and 35, the air hole 39, and the auxiliary air hole 40. It is. If air is not supplied to the piston chamber 11, the needle valve 5 closes the inside of the liquid spray port 4 by the force of the spring 45 (state of FIG. 2). Accordingly, the liquid flow flows to the liquid supply port 7, the passage 13, and the liquid return port 8, and the liquid circulates.

  Spray working condition

  When the valve V1 is opened and air is supplied from the compressor C to the piston chamber 11, air pressure is applied to the piston chamber 11, and the seal member 41 is pressed and moved to the right in FIG. When the seal member 41 moves, the needle valve 5 moves to open the liquid spray port 4 of the nozzle 20 and move to a preset insertion position of the nozzle 20 into the liquid spray port 4 (in FIG. 1). State).

  At this time, the end surface 48a of the needle valve 5 comes into contact with the periphery of the hole 49, the liquid does not flow to the liquid return port 8 side, the liquid flow flows to the liquid supply port 7 and the liquid chamber 10, and the pipe 57 has a liquid. Will not stay.

  Further, by opening the valves V2 and V3 simultaneously with the valve V1, air flows from the pattern air supply port 9c and the atomizing air supply port 9b to the air hole 36, the air hole 39, and the auxiliary air hole 40, and the air is ejected. Spray in a predetermined spray shape.

  Therefore, since the valve mechanism 47 for switching the flow path by pressure is built in the spray gun 1 in the conventional case where an external valve device is provided for liquid circulation, the entire coating system apparatus including the spray gun is provided. In addition to simplification and cost reduction, it is possible to switch quickly without requiring a control device such as a valve, thereby saving resources. In addition, since the liquid can be circulated at all times, the liquid does not stay in the pipe, precipitate, and be separated.

  By this, since spray quality is ensured, it can be used industrially in comfort.

  The spray structure of the spray section 3 and the seal structure of the needle valve 5 of the needle opening / closing mechanism 6 in the embodiment may be a conventionally known structure and is not limited to the embodiment. The liquid may be a paint or a water-based coating material that provides an acid-resistant protective coating for a solid pharmaceutical preparation.

It is sectional drawing which shows the state which the liquid spraying port of the spray gun which shows embodiment of this invention opened. It is sectional drawing which shows the state which the liquid spraying opening of the spray gun of this invention obstruct | occluded. It is a principal part disassembled perspective view of this invention. It is a perspective view which shows the piping state of the liquid and air to a spray gun.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spray gun 2 Body part 3 Spray part 4 Liquid spray port 5 Needle valve 6 Needle opening / closing mechanism 7 Liquid supply port 8 Liquid return port 9a Needle valve operation air supply port 9b Atomized air supply port 9c Pattern air supply port 10 Liquid chamber 11 Piston Chamber 20 Nozzle 21 Air cap 23 Ring 46 Support ring 47 Valve mechanism

Claims (2)

  A liquid supply port for supplying a liquid, a liquid spray port for spraying the liquid with a needle valve, and a liquid return port for returning the liquid when the liquid spray port is closed, the liquid supply port and the liquid In the passage between the return port and the needle valve, the liquid is prevented from flowing to the liquid return port when the liquid spray port is opened, and the liquid is supplied to the liquid return port when the needle valve is closing the liquid spray port. A spray gun characterized by providing a valve mechanism for flowing water.   2. The spray gun according to claim 1, wherein the valve mechanism is formed of an end face formed in the needle valve and a seal member provided in the passage.

Images