Applicator, in particular rotary atomiser

Patent metadata

Field	Value
Publication number	US-11623232-B2
Application number	US-202016991083-A
Country	US
Kind code	B2
Filing date	Aug 12, 2020
Priority date	Jul 3, 2015
Publication date	Apr 11, 2023
Grant date	Apr 11, 2023

Abstract

The disclosure relates to an applicator (RZ), in particular a rotary atomizer, for the application of a coating agent, in particular a two-component paint, comprising a first coating agent connection (SL) for feeding a first coating agent, in particular a basic resin of a two-component paint, a first coating agent strand (L1-L4), which extends in the applicator (RZ) from the first coating agent connection (SL) and carries the first coating agent, and a first valve (SLV1), which is arranged in the first coating agent strand (L1-L4) and controls the flow of the first coating agent, wherein the first valve (SLV1) can be controlled by a first control signal. It is proposed that a first pressure-relief valve (SLV1), which is actuated by its own medium, is arranged in the first coating agent strand (L1-L4) and, to avoid a problem being caused by excessive pressure, opens automatically when the pressure upstream of the first pressure-relief valve (SLV1) exceeds a certain maximum pressure.

First claim

The invention claimed is:

1. Application device for applying a coating agent, comprising:
a) a first coating agent connection for supplying a first coating agent,
b) a first coating agent line which leads in the application device from the first coating agent connection and guides the first coating agent,
c) a first overpressure valve which is arranged in the first coating agent line and controls the flow of the first coating agent, the first overpressure valve being controllable by a first control signal, the first overpressure valve being own-medium-actuated which, in order to avoid an overpressure fault, opens automatically when pressure upstream of the first overpressure valve exceeds a specific maximum pressure,
d) the first overpressure valve is a needle valve having a valve seat and a displaceable valve needle, the disposable valve needle having a needle stem and a needle head, wherein the needle head closes the valve seat when the valve needle is in a closed position, and whereas the needle head frees the valve seat when the valve needle is in an open position, and
e) a valve drive for displacing the valve needle the valve drive having:
e1) a displaceable piston which acts upon the valve needle in order to displace the valve needle, and
e2) a valve spring which acts upon the piston or the valve needle with a spring force, and the spring force of the valve spring in the closed position and in the open position is at least 20 N and not more than 400 N.

2. Application device according to claim 1 , further comprising
a flexible membrane which surrounds the valve needle upstream of the needle head in an annular and sealing manner.

3. Application device according to claim 2 , wherein
a) the valve needle is displaceably arranged in a valve chamber, wherein the valve chamber is cylindrical at least in part,
b) the membrane is fixed in the middle to the needle stem of the valve needle in a sealing manner, and
c) the membrane is fixed by its peripheral edge to the inside wall of the valve chamber in a sealing manner.

4. Application device according to claim 3 , further comprising
a coating agent inlet for supplying the coating agent, wherein the coating agent inlet opens into the valve chamber on the side of the membrane remote from the valve drive, so that the membrane seals the valve drive with respect to the valve chamber filled with coating agent, and
a coating agent outlet for discharging the coating agent, wherein the coating agent outlet opens into the valve seat so that, when the valve needle is in the open position, the coating agent is able to flow through the valve seat to the coating agent outlet.

5. Application device according to claim 4 , wherein the valve drive has
a control air inlet for supplying control air, wherein the control air acts upon the piston in order to displace the piston and thus also the valve needle.

6. Application device according to claim 5 , wherein
a) the valve spring pushes the valve needle in the direction towards the closed position, and
b) the control air pushes the valve needle, via the piston, in the direction towards the open position,
c) the valve spring and the needle head are arranged on opposite sides of the piston,
d) the piston has a piston diameter of at least 5 mm in order to generate an opening force when the valve needle moves into the open position,
e) the control air requires a control air pressure of less than 6 bar to move the valve needle into the open position, so that the control air can be obtained from a conventional 6-bar compressed air network.

7. Application device according to claim 5 , wherein
a) the valve spring pushes the valve needle in the direction towards the closed position with a specific closing force,
b) the pneumatic valve drive, when pneumatically actuated, pushes the valve needle in the direction towards the open position with a specific opening force,
c) the opening force is greater by a specific opening force excess than the closing force, so as to be able to open the needle valve if the needle head adheres to the valve seat,
d) the opening force excess is greater than 20 N.

8. Application device according to claim 2 , wherein
a) above a specific opening pressure, the coating agent pressure at the coating agent inlet pushes the valve needle, via the membrane, out of the closed position into the open position,
b) the membrane has a membrane diameter of at least 3 mm and not more than 40 mm,
c) the opening pressure of the coating agent at the coating agent inlet is at least 8 bar and not more than 38 bar.

9. Application device according to claim 2 , wherein
a) the valve seat narrows in the direction of flow with a specific seat angle,
b) the needle head narrows in the direction of flow with a specific head angle,
c) the seat angle is substantially equal to the head angle,
d) the seat angle is greater than 20° and smaller than 70°,
e) the head angle is greater than 20° and smaller than 70°.

10. Application device according to claim 2 , wherein
a) an additional sealing element is installed in the needle head of the valve needle in order to seal the valve seat in the closed position, and
b) the sealing element is made of a different material than the needle head of the valve needle, and
c) the sealing element is made of a resilient material.

11. Application device according to claim 10 , wherein the sealing element is made of perfluoro rubber.

12. Application device according to claim 10 , wherein the sealing element is moulded onto the needle head.

13. Application device according to claim 10 , wherein the sealing element is a sealing ring which is installed in an annular groove in the needle head.

14. Application device according to claim 10 , wherein the needle head is made of titanium.

15. Application device according to claim 10 , wherein
a) the needle head of the valve needle tapers substantially conically in the direction of flow,
b) the valve seat tapers substantially conically in the direction of flow,
c) the needle head has in its conical lateral surface an annular groove in which the sealing element is installed,
d) the conical lateral surface of the needle head forms an annular peripheral supporting surface upstream of the sealing element and rests with the supporting surface on the valve seat,
e) the needle head has in the supporting surface at least one flushing groove running axially which, when the valve needle is in the closed position, allows flushing medium to pass from the valve chamber to the sealing element.

16. Application device according to claim 15 , wherein the flushing groove has a groove width of at least 1 mm.

17. Application device according to claim 10 , wherein
a) the needle head has a rigid stop and, in the closed position, rests with the stop on the valve seat, and
b) when the valve needle is in the closed position, the sealing element in the needle head is exposed to a pressure which is independent of the closing force acting upon the valve needle, since the needle head is resting with its rigid stop on the valve seat.

18. Application device according to claim 2 , wherein
a) the valve needle is not sealed by an additional seal, and
b) the curing agent comprises isocyanate, and
c) the needle stem of the valve needle has a diameter which is greater than 2 mm and smaller than 10 mm, and
d) the valve needle has a maximum needle stroke of less than 3 mm.

Assignees

• Duerr Systems Ag

Inventors

• Herre Frank
• Michelfelder Manfred
• Baumann Michael
• Hermann Sascha
• Seiz Bernhard
• Buck Thomas

Classifications

• B05B1/306

  the actuating means being a fluid · CPC title

• B05B7/0408 Primary

  with arrangements for mixing two or more liquids · CPC title

• B05B12/087 Primary

  Flow or presssure regulators, i.e. non-electric unitary devices comprising a sensing element, e.g. a piston or a membrane, and a controlling element, e.g. a valve · CPC title

• B05B15/14

  Arrangements for preventing or controlling structural damage to spraying apparatus or its outlets, e.g. for breaking at desired places; Arrangements for handling or replacing damaged parts · CPC title

• B05B3/1014

  with a spraying edge, e.g. like a cup or a bell · CPC title