2007年4月26日星期四

Introduction of flameout protector

http://tafe.blogbus.com/files/11775917610.doc
The purpose of flameout protector: When we use the cook top, the fire may be extinct because of the wind or overflowing water. In this case, the protector may cut off gas to prevent some accidents happening because of its leakage, such as poisoning, explosion or fire. In this way, it realizes its safety protection function.
Working sketch-map of flameout protector
The first step: Piezoelectricity.

The second step: Valve-open condition.
The top of the thermocouple is heated by fire, and it causes thermo electromotive force. Then it will be in series between the closed circuit and the valve. Outside force and the magnetic field breathe the valve and keep it open, and the gas channel is open.
The third step: Cut off gas in sudden flameout condition.
When the fire is extinct because of wind or overflowing water, the thermo electromotive potential will minish quickly, and the ferrite core will come back to its original place to cut off the gas because of the loss of the spring effect.
Attention:
1. Thermocouple
1) There mustn’t be any damage or peeling off for the cover of insulation wire or insulation sleeve, otherwise it will cause short circuit, which will influence the normal operation of the valve.
2) The fix-up of the thermocouple must dissipate heat to reduce the heat accumulation of fixing board and thermocouple copper. This can shorten the valve-closing time when there is sudden flameout.
3) The heated part of a thermocouple must be on the top of 2-3mm. Not to put the top into the fire, otherwise it may reduce the potential and shorten its life.

2. Solenoid valve
1) Prevent the valve from being strongly striken in the process of installation and shipment, otherwise it may influence its normal performance.
2) Before installation, the user must check the valve flatly on the test clamps with some prepressing. It is not allowed to be freely-flip. This assures that magnetic material won’t be damaged by colliding, otherwise it will influence the magnetic force.
3) Clean the impurity such as aluminum or oil left on the inner wall of the stove and the surface of the valve.
4) Keep the good connection of the solenoid valve and thermocouple. Prevent the safety protection device from operating abnormally because of too big contact resistance.
5) The warehouse of solenoid valves must be dry and ventilated and strictly prohibit extrusion.

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