JPS63187020A - Gas pressure proportional valve - Google Patents

Abstract

PURPOSE:To prevent worsening or an air-fuel ratio, by a method wherein, even when a gas valve for switching is situated on the downstream side of a gas pressure control type proportional valve, unbalance occurring to the nozzle pressure of a burner is prevented from increasing. CONSTITUTION:A partition 7, having a small opening part, incurring a pressure loss higher than that of a switching gas valve and the like, is formed in a gas passage extending to a first burner group 5 not through a switching gas valve 4. When the first burner group 5 and a second burner group 6 simultaneously perform combustion, a combustion amount of the first burner group is set to a value lower than that of the second burner group. Thereby, when, with the switching gas valve 4 closed, only the first burner group 5 effects combustion, a pressure loss of the passage on the secondary side of a proportional valve is decreased with the decrease in a total flow rate. The small opening part of the partition wall is set so that, when a nozzle pressure is increased, the nozzle pressure of the first burner group is increased over that of the second burner group. This constitution prevents large disturbance of an air-fuel ratio occasioned by opening and closing of the switching gas valve, and provides stable combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a gas pressure proportional valve for varying the combustion amount of a gas water heater or the like.

BACKGROUND ART In order to widen the variable range of combustion amount in gas water heaters, etc., means have been adopted to increase or decrease the number of burners using a switching gas valve. However, the gas pressure, which is set constant with the gas pressure control type proportional valve, is branched into the gas passage that goes through the switching gas valve and the gas passage that does not go through the switching valve, and is completely supplied to the burner, resulting in an imbalance in the passage pressure drop. This results in different burner nozzle pressures. For this reason, the amount of combustion in the burner section that does not go through the switching gas valve increases with the same nozzle diameter.

Furthermore, when the switching solenoid valve closes, the pressure loss from the downstream passage of the proportional valve to the branch point decreases by l/- as the gas flow rate decreases.
1, the nozzle pressure in the burner section that does not go through the switching valve further increases, resulting in a larger combustion amount, resulting in an excessive increase in the amount of gas and a worsening of the air-fuel ratio.

Problems to be Solved by the Invention The present invention solves these conventional problems. Even if a switching gas valve is provided on the downstream side of the gas pressure control type proportional valve, the imbalance in the burner nozzle pressure does not become large. The purpose is to prevent the air-fuel ratio from becoming worse.

Means for Solving the Problems In order to achieve this object, the present invention provides a gas path leading to the first burner group that does not pass through the switching gas valve downstream of the proportional valve, and has a pressure higher than the pressure loss caused by the switching gas valve, etc. A partition wall is provided with a small opening that causes loss.

Function: With this configuration, the pressure imbalance on the secondary side of the proportional valve can be reduced.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, 1 is a gas pressure controlled proportional electromagnetic drive unit, 2 is a gas governor unit, 3 is a secondary side connection unit, 4 is a switching gas valve, 5 is a nozzle of the first burner group, and 6 is a second burner group. The nozzle 7 of the burner group is a partition wall having a small opening.

The gas pressure set by the gas governor part 2 of the gas pressure control type proportional valve passes through the secondary side connection part 3 and is supplied to the second burner group via the switching gas valve 4, the switching gas valve, etc. The gas is supplied to the first burner group through the partition wall 7, which sets a pressure loss larger than that of the gas pressure loss by the shape and size of the small opening. The relationship between the total gas amount Q and the burner pressure is shown in Figure 2. The nozzle pressure of the second burner group is A, and the nozzle pressure of the first burner group without the partition wall 7 is less than 100% due to the small pressure loss. Become. This is the nozzle output of the first burner group when the partition wall 7 is provided.

In this way, when the first burner group and the second burner group burn simultaneously, the combustion amount of the first burner group is set to be smaller than the combustion amount of the second burner group, so the switching gas valve 4 is closed. Therefore, when only the first burner group 5 burns, the pressure loss in the secondary passage of the proportional valve becomes smaller as the overall flow rate decreases, and when the nozzle pressure increases, the nozzle pressure of the second burner group increases. The small opening in the partition wall is set to be larger. Therefore, the air-fuel ratio does not vary greatly due to opening and closing of the switching gas valve, and stable combustion can be obtained.

Advantages of the Invention (1) Since a partition wall having a small opening is provided in the gas passage, the nozzle diameters of the first burner group and the second burner group may be the same, and there is no risk of incorrect installation.

(2) Since the nozzle pressure imbalance due to opening and closing of the switching gas valve can be set within the range of the appropriate air-fuel ratio of the burner, stable combustion can be obtained without the risk of incomplete combustion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a gas pressure proportional valve showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the overall gas flow rate and burner nozzle pressure. DESCRIPTION OF SYMBOLS 1... Electromagnetic drive unit, 2... Gas governor unit, 4... Switching gas valve, 5... First burner group, 6... Marked No. 2 burner groups, 7... bulkhead. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
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Claims (1)

[Claims] Branching the gas passage leading to the first burner group and the second burner group,
A switching gas valve is provided in the passage leading to the second burner group, and the passage leading to the first burner group is provided with a partition wall having a small opening that causes a larger pressure loss than the switching gas valve. proportional valve.