JPH08128609A - Fan equipped with fuel gas mixing mechanism - Google Patents

Abstract

PURPOSE: To provide a fan, equipped with a fuel gas mixing mechanism, preventing the leakage of fuel gas surely and very high in safety property, in a fuel gas mixing mechanism, in which combustion air and fuel gas are mixed in the casing of the fan. CONSTITUTION: An air chamber 2, having a suction port 1, a fuel gas chamber 4, having a fuel gas supplying port 3, an impeller chamber 6, having a discharging port, are arranged sequentially and these air chamber 2, fuel gas chamber 4 and impeller chamber 6 are communicated through a communicating hole 7, formed at the center of the impeller chamber substantially, while a fuel gas inflow unit 8 from the fuel gas chamber 4 to the communicating hole 7 is constituted of an ejector nozzle structure. The motor shaft 10 of a motor 9 is inserted into the communicating hole 7 while forming a predetermined gap between the fuel gas inflow unit 8 while an impeller 11 is connected to the tip end of the motor shaft 10 in the impeller chamber 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a blower used in a premix type burner.

[0002]

2. Description of the Related Art Generally, a premixing burner has a structure in which a fuel gas is mixed with combustion air at a position upstream of a combustion section, and therefore the supply pressure of the fuel gas must be relatively high. As a method of allowing the fuel gas to be mixed even when the supply pressure is low, there is a method in which the fuel gas is supplied to the suction port of the blower so that the combustion air and the fuel gas are mixed and sucked into the casing of the blower. However, this structure has a problem that fuel gas easily leaks from the bearing portion of the motor shaft to which the impeller is connected. In order to prevent the fuel gas from leaking, it is necessary to use a bearing unit having very high airtightness, which increases the cost of the blower as a whole.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a system for mixing combustion air and fuel gas in the casing of a blower, which surely prevents the fuel gas from leaking and has a very high safety. An object is to provide a blower provided with a fuel gas mixing mechanism.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides an air chamber having a suction port, a fuel gas chamber having a fuel gas supply port, and an impeller chamber having a discharge port. Arranged in order, these air chamber, the fuel gas chamber and the impeller chamber are communicated with each other through a flow hole formed in a substantially central portion thereof, and a fuel gas inflow portion from the fuel gas chamber to the flow hole has an ejector nozzle structure, The motor shaft of the motor is inserted into the flow hole with a predetermined gap between the fuel gas inflow portion and the fuel gas inflow portion, and the impeller is connected to the tip of the motor shaft in the impeller chamber.

[0005]

In the above structure, the combustion air flowing in from the suction port flows into the impeller chamber through the flow hole. At this time, the fuel gas inflow portion from the fuel gas chamber to the flow hole has the ejector nozzle structure. Therefore, the fuel gas in the fuel gas chamber is sucked into the flow of the combustion air, and the combustion air and the fuel gas are mixed and flow into the impeller chamber. The mixed gas of the combustion air and the fuel gas, which has flowed into the impeller chamber, is supplied to the premix burner through the discharge port.

[0006]

The preferred embodiments of the present invention will be described below. 1 and 2, an air chamber 2 having a suction port 1, a fuel gas chamber 4 having a fuel gas supply port 3, and an impeller chamber 6 having a discharge port 5 are arranged in this order. The chamber 4 and the impeller chamber 6 are communicated with each other through a flow hole 7 formed in a substantially central portion thereof. In the illustrated embodiment, the suction port 1 of the air chamber 2 is formed in the peripheral surface portion of the air chamber 2, and the suction port 1 is equipped with a filter 12. The fuel gas supply port 3 is connected to an external fuel gas supply pipe (not shown). The discharge port 5 of the impeller chamber 6 is formed in the peripheral side wall of the impeller chamber 6 and is opened in the tangential direction. The discharge port 5 communicates with a burner (not shown).

The fuel gas inflow portion 8 from the fuel gas chamber 4 to the flow hole 7 has an ejector nozzle structure,
When the combustion air flowing in through the suction port 1 flows from the air chamber 2 toward the impeller chamber 6 through the flow hole 7, the fuel gas is sucked. The cross-sectional area of the flow hole 7 is relatively small, and the flow rate of the combustion air is increased at a high speed, and the action of the flow causes the fuel gas inflow portion 8 having the ejector nozzle structure to have a negative pressure, resulting in combustion. Fuel gas is sucked into the flow of air for use. Therefore, even if the supply pressure of the fuel gas is relatively low, the fuel gas can be efficiently mixed with the combustion air, and the fuel gas does not flow back to the air chamber 2 side.

A motor shaft 1 of a motor 9 is provided in the through hole 7.
0 is inserted from the air chamber 2 side. Between the motor shaft 10 and the fuel gas inflow portion 8, a gap of a predetermined size,
That is, a gap having a size that does not hinder the flow of combustion air and fuel gas is formed. An impeller 11 is connected to the tip of the motor shaft 10 in the impeller chamber 6. Since the motor 9 is fixed via the air chamber 2, the fuel gas does not leak from the bearing portion of the motor shaft 10 to the outside, and a relatively low airtight bearing, that is, an inexpensive bearing can be used. In addition, even if an unexpected situation occurs and the flame comes back from the burner, the air chamber 2
Since it has been installed, it is highly explosion-proof.

A pressure sensor 1 is installed in the fuel gas inflow portion 8.
3 is provided, and based on the detection signal from the pressure sensor 13, it is confirmed that the fuel gas inflow portion 8 is in a negative pressure state, that is, the blower is operating normally, Gas is supplied (opening and closing of a solenoid valve for supplying fuel gas). By doing so, leakage of the fuel gas can be prevented more reliably.

Next, the operation of the above configuration will be described. By operating the motor 9, the impeller 11 is rotated and the combustion air is flown in through the suction port 1. The combustion air flowing in through the suction port 1 flows along the motor shaft 10 and flows into the impeller chamber 6 through the flow hole 7,
At that time, since the fuel gas inflow portion 8 from the fuel gas chamber 6 to the flow hole 7 has an ejector nozzle structure, the fuel gas in the fuel gas chamber 6 is sucked into the flow of combustion air. The sucked fuel gas flows into the impeller chamber 6 while being mixed with the combustion air. Then, the mixing of the combustion air and the fuel gas is promoted in the impeller chamber 6, and then the mixed gas of the combustion air and the fuel gas is supplied to the premix burner located downstream of the discharge port 5.

In another embodiment, the motor 9
Is completely stored in the air chamber 2, and the suction port 1 is connected to the motor 9
Can be provided on the end face side of the motor so that the combustion air flows around the motor 9. According to this configuration, the combustion air flowing around the motor 9 serves to cool the motor 9.

[0012]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it is possible to use a fuel gas having a low supply pressure, and when the combustion air and the fuel gas are mixed in the casing of the blower, the fuel gas is used. It is very safe because it can surely prevent gas leakage. That is, when the combustion air flows through the flow hole along the motor shaft, the flow speed of the combustion air is increased and the combustion air flows at high speed, and the action of the flow causes the fuel gas to flow from the fuel gas inflow portion having the ejector nozzle structure. Because of the suction structure, even if the supply pressure of the fuel gas is relatively low, the fuel gas can be efficiently mixed with the combustion air, and the fuel gas does not flow back to the air chamber side. Further, since the motor is fixed via the air chamber, the fuel gas does not leak from the bearing portion of the motor shaft to the outside, and an inexpensive bearing can be used.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a right side view of FIG.

[Explanation of symbols]

 1 Suction Port 2 Air Chamber 3 Fuel Gas Supply Port 4 Fuel Gas Chamber 5 Discharge Port 6 Impeller Chamber 7 Distribution Hole 8 Fuel Gas Inlet 9 Motor 10 Motor Shaft 11 Impeller

Claims (1)

[Claims] 1. An air chamber 2 having a suction port 1, a fuel gas chamber 4 having a fuel gas supply port 3, and an impeller chamber 6 having a discharge port 5 are arranged in order, and these air chamber 2 and fuel gas chamber 4 are arranged. Further, the impeller chamber 6 is communicated with the flow hole 7 formed in the substantially central portion thereof, and the fuel gas inflow portion 8 from the fuel gas chamber 4 to the flow hole 7 has an ejector nozzle structure. A fuel characterized in that a motor shaft 10 of a motor 9 is inserted into the fuel gas inflow portion 8 with a predetermined gap formed therein, and an impeller 11 is connected to the tip of the motor shaft 10 in the impeller chamber 6. Blower equipped with gas mixing mechanism.