The method and structure of controlling the opening of the gas proportional valve by using the wind speed of the exhaust fan

Abstract

The invention provides a method and structure for controlling the opening degree of a fuel gas proportional valve through the air speed of an exhaust fan. According to the method and structure, the opening degree of the proportional valve is indirectly controlled by enabling the air speed of the exhaust fan to generate negative pressure according to the Venturi tube principle and then enabling the negative pressure to be multiplied through a negative pressure membrane with a large acting area. When the air speed of the exhaust fan is increased and the negative pressure is increased proportionally through a Venturi tube, the negative pressure membrane enlarges the negative pressure power at a high area ratio, then the pressure relief opening degree of a small valve plug of a pressure-relief cavity can be reduced so that the back pressure of a back pressure membrane can be increased reversely, and accordingly the air speed of the exhaust fan can be reflected accurately to control the opening degree of the fuel gas proportional valve; particularly, when an air duct of a fuel gas water heater is badly blocked, the proportional valve can be correctly closed due to the fact that no air speed or negative pressure is generated, so that the method and structure have remarkable practical value on the aspect of security.

Description

technical field [0001] The present invention is a proportional valve used in a forced exhaust type gas water heater, which aims to generate negative pressure by using the wind speed of the exhaust fan, and amplifies the force of the negative pressure proportionally to control the opening of the valve plug of the proportional valve , so that the two can increase or decrease synchronously in a proportional and positively correlated manner. Background technique [0002] Gas water heaters are common household equipment that use gas (gas) as raw material to burn and heat. However, it is inevitable that there will be problems of carbon monoxide overflow due to incomplete combustion during operation. Such safety concerns make gas water heaters with forced ventilation function As more and more people use it, especially in community buildings with narrow balconies, the forced-air gas water heater has almost become the first choice for residents to install. [0003] The so-called for...

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Problems solved by technology

[0007] Although the above-mentioned prior art "direct-pressure water heater" discloses a concept of synchronously controlling the proportional valve by the exhaust fan, however, after research by the inventor, it is obvious that this method cannot be implemented in practice

The main reason is that this technology intends to use the wind pressure to directly introduce the proportional valve to open the valve against the gas supply pressure, but the wind pressure of the exhaust fan can reach several hundred Pa (ie hPa) at most, and the gas in the closed gas pipeline The gas supply pressure reaches several thousand Pa (kPa), and it is practically impossible to directly introduce the extremely weak air pressure to directly drive the gas pressure with high pressure; The way of proportional driving is obviously impossible to implement!

[0008] In addition to practical problems, more importantly, this method has a major lack of security! As we all know, the outlet of the exhaust pipe of the forced-air gas water heater extends to the outside, and sometimes there will be such things as small birds nesting and causing the air duct to be blocked. When the blockage reduces the exhaust air volume, the wind pressure (positive pressure) in the air duct will increase instead, resulting in an increase in the opening of the proportional valve and an increase in the gas flow rate. The bigger the flame!

[0009] The more serious the blockage of the air duct and the greater the wind pressure, the gas supply and flame will not be reduced, but will become larger in disguise, which not only violates the original design intention of accurately controlling the gas flow by wind pressure, but also in It is even more dangerous in terms of safety, especially when the air duct is blocked, the gas supply will increase and the amount of carbon monoxide produced will also increase. When the amount of carbon monoxide increases and the concentration of carbon monoxide produced by incomplete combustion cannot be effectively eliminated, it is more likely to cause safety problems

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