Valve unit for an electrostatic coating installation

• US 20060169937A1
• Filed: 03/27/2002
• Published: 08/03/2006
• Est. Priority Date: 03/29/2001
• Status: Active Grant

• Current Assignee: Durr Systems Incorporated (Durr AG)
• Original Assignee: Durr Systems Incorporated (Durr AG)
• Inventors: Poppe, Seigfried, Herre, Frank, Baumann, Michael, Krumma, Harry, Nolte, Hans J., Giuliano, Stefano
• Granted Patent: US 7,275,702 B2
• Time in Patent Office: Days
• US Class Current: 251/129.40
• CPC Class Codes: B05B 1/306 the actuating means being a fluid
• CPC Class Codes: B05B 5/04 characterised by having rotary outlet or deflecting elements , i.e. spraying being also effected by centrifugal forces
• CPC Class Codes: Y10T 137/8242 Electrical

Abstract

The main needle valve of an electrostatic atomizer has an opto-electronic sensor device with optical waveguides whose faces are opposite a reflecting element of a component moveable with the valve needle for potential-free switch position interrogations.

Claims

1. A valve unit for an electrostatic installation for series coating of workpieces, comprising a remote-controlled switchable valve whose moveable valve element is moveable between two switch positions and in one switch position releases a path for a medium flowing through the valve, whereas said valve is closed when said valve element is situated in its other switch position,

wherein for interrogation of the switch position of said valve and for generation of a corresponding interrogation signal, an opto-electronic sensor device with at least one optical waveguide sensing movement of said valve element between at least two switch positions.

2. The valve unit according to claim 1, where said moveable component has at least one optically reflecting surface opposite a sensor surface of said optical waveguide when said valve element is situated in the switch position to be reported.

3. The valve unit according to claim 1, comprising one optoelectronic sensor device with at least one optical waveguide is provided for each of the switch positions.

4. The valve unit according to claim 1, wherein said moveable valve element is the valve needle of a needle valve.

5. The valve unit according to claim 4, wherein said moveable component is a shaft element mounted coaxial to valve needle on a piston of a pneumatic valve drive, said shaft element being moveable in a recess of a valve housing, into which a radial opening with respect to an axis of said valve needle leads for said optical waveguide.

6. The valve unit according to claim 1, wherein said moveable valve element is connected to the diaphragm of a diaphragm valve.

7. The valve unit according to claim 1, wherein said optical waveguides form at least one light barrier for said moveable component.

8. The valve unit according to claim 1, wherein a magnetically active transmitter element is arranged on said moveable component, that a sensor element is provided that contains an optical polarization device, that by approach of the transmitter element the polarization of the light guided through said polarization device is varied in said sensor element magneto-optically to generate a light signal, and that an optical waveguide arrangement is connected to said polarization device, which leads to a remote electronic device to generate an electric signal corresponding to said light signal.

9. The valve unit according to claim 8, wherein said sensor element contains a reflector that guides the light coming from said polarization device back to an analyzer of said polarization device, in which a refraction element that rotates the direction of polarization is situated between said polarization device and said reflector and that a light guide for the light fed to the sensor element and said light guide for the light fed to said remote electronic device are connected to said polarization device.

10. Said valve unit according to claim 9 wherein said moveable component includes two signal generation elements spaced from each other in the direction of displacement, said first element of which triggers a binary signal of said sensor device when the valve element is situated in one switch position, whereas said second signal generation element triggers the binary signal of said sensor device with the valve element situated in its other switch position.

11. The valve unit according to claim 10, wherein said two signal generation elements of said moveable component are formed from optically reflecting surfaces.

12. The valve unit according to claim 10, wherein said two signal generation elements are formed by light barrier openings.

13. The valve unit according to claim 10, wherein said two binary signals have the same binary value and that said sensor signal of the sensor device is switched to the opposite binary value when said moveable component is shifted between its two positions.

14. The valve unit according to claim 10, comprising an electronic control device with which it is established that the binary signal appears within a stipulated time after generation of the control signal for switching of said valve and that otherwise an alarm signal is generated.