CS256125B1 - Equipment for fire safety in paint shops - Google Patents

Abstract

A device for ensuring fire safety in paint shops is provided, consisting of a workplace fire hazard sensor, a measuring center, signaling circuits and a fire extinguishing device. In this device, at least one integrated fire hazard sensor contains a combustion sensor and an electric discharge sensor, whereby the output signal of the combustion sensor and the output signal of the electric discharge sensor are fed to a logic decision block, the output of which is connected to the input of the measuring center, the action signals of which are fed to the circuits of acoustic and optical fire hazard signaling and, at the same time, to the fire extinguishing device.

Description

BACKGROUND OF THE INVENTION The present invention relates to a fire safety device for paint shops comprising a fire hazard sensor for a workplace, a measuring center, signaling circuits and a fire extinguisher.

When spraying liquid paints in paint shops, a mixture of solvent vapors and air aerosols forms at the spray gun mouth. This creates an environment with a high probability of ignition. Ignition of the paint cloud or local explosion can occur for a variety of reasons. The local ignition of the paint, referred to as ignition, can shortly turn into a fire in the spray booth or when the paint remains in a larger explosion. Therefore, when operating a paint shop, applying liquid paint, it is necessary to provide an indication of fire hazard to the operation with automatically derived subsequent interventions, ensuring safety.

At present, safety systems are known consisting of a set of ignition sensors, a control panel and a fire extinguisher. The signals of the ignition sensors are processed in the control panel. Action outputs of the control panel control optical and acoustic signaling of the state of danger of fire safety of operation and starting of fire extinguishing equipment. At the same time, they prevent further ignition of the paint by causing interference with the coating technology. The fire detectors used in the fire safety system react without delay to the ignition of the paint. They are not sensitive to daylight and artificial light or to electrical discharges in the cab. The sensors work on the principle of indicating the infrared spectrum emitted by the incoming flame. Technological orientation towards spraying of liquid paints in the high voltage electric field increases the risk of possible ignition, caused by electric discharge around the gun or from ungrounded sprayed product, eventually in case of disturbance of high voltage distribution. A fundamental problem with current safety systems is that the burn-in sensors are not sensitive to electrical discharges. They respond selectively only to flame with indication sensitivity usually up to 5 meters at a viewing angle usually up to 100 °. Thus, they indicate and as a result of the initiation of a fire hazardous condition, the formation of a flame, not its possible cause.

These drawbacks are overcome by the fire safety device of the paint shop according to the invention, characterized in that at least one integrated fire hazard sensor comprises a fire sensor and an electric discharge sensor, the sensor output signal being burnt and the electrical discharge sensor output signal the logical decision block, the output of which is connected to the input of the control panel, whose action signals are routed to the acoustic and optical fire alarm signaling circuits and simultaneously to the fire extinguishing equipment.

The greater effect of the invention is manifested in many ways. The device works on the principle of detecting the occurrence of a fire hazard and broadens the indication sensitivity of the sensing system, while at the same time modifying the nature of action interventions in operation. This increases the reliability of operation, which in the case of automated paint shops with the use of industrial robots and manipulators without human operation must be reliably automatically secured against fire or explosion. The integrated sensor for fire hazard in the paint shop can distinguish both electric discharge and combustion, local ignition of the paint, eventually spreading fire in the spray booth. Indication of electric discharge, which is the predominant cause of ignition when applying liquid paint spraying technology in the high-voltage electric field, increases the safety of automatic operation when deriving interventions in the process. When using an integrated sensor on a robotized workplace, the ability to terminate the system is considerably extended by the initial information about the possible fire hazard of the workplace safety. At the same time, the chance of subsequent ignition of the paint is reduced by the action of an electric discharge. Another advantage of the device is the possibility to combine multiple integrated sensors in the spray booth and to evaluate the measured data of the occurrence of electric discharge and ignition with adjustable decision logic in the measuring center.

An exemplary embodiment of the device according to the invention is shown schematically in the attached drawing.

The whole of this device comprises one integrated sensor 11, the output of which is routed to a measuring center g connected to the acoustic and optical signaling circuits 2 and to the fire extinguisher 4. The integrated sensor assembly 7 comprises a burner sensor 11 and an electric discharge sensor 12. The burner sensor 11 is designed, for example, as a light-sensitive system that responds selectively to the infrared spectrum emitted by the flame. The electric discharge sensor 12 is, for example, designed as a system selectively reacting to light spectrum components. Both the sensors 11 and 12 and the logic decision block 13 are built into the mechanical housing 14 in an embodiment meeting the explosive environment requirements of the paint shop. The sensor signals 11 and 12 are routed to a logical decision block 13. The decision system implements, for example, a truth table:

Sensor signal Output Action of electric shock

0 0 0 1 1 10 2 1 1 2

AND

(B)

C

C where action A characterizes safe operation of the workplace. It is used on the control panel to signal fire safe operation. Action B is triggered at the first level of fire hazard that could turn into a larger fire or explosion. It eliminates the source of electrical discharge and turns off the high voltage generator. Action C is triggered at the second stage of fire hazard. It turns off not only the high voltage generator, but also closes the paint distribution system and opens the local extinguishing system.

Claims (1)

Fire safety equipment in paint shops, comprising a workplace fire hazard sensor, a control panel, signaling circuits and a fire extinguisher, characterized in that at least one integrated fire hazard sensor (1) comprises a fire sensor (11) and an electric discharge sensor (12) ), the output of the ignition sensor (11) and the output of the electric discharge sensor (12) being connected to a logic decision block (13), the output of which is connected to the input of the control panel (2). optical signaling (3) of fire hazard and at the same time to fire extinguishing equipment (4).