Automatic temperature and humidity regulation – Furnace controlled – Furnace controlled responsive to combustion products...
Reexamination Certificate
2000-05-31
2002-02-12
Tapolcai, William E. (Department: 3744)
Automatic temperature and humidity regulation
Furnace controlled
Furnace controlled responsive to combustion products...
C431S051000, C431S053000
Reexamination Certificate
active
06345768
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control valve for a constantly pilot flaming type vessel gas water heater in which the temperature of hot water in a reservoir can automatically be controlled to a desired level.
2. Description of the Related Art
Such a conventional control valve for a vessel gas water heater has, for example, a main burner governor valve unit MGV′ provided across a main gas passage and a pilot burner governor valve unit PGV′ provided across a pilot gas passage as shown in FIG.
3
. The main burner governor valve unit MGV′ is arranged in that, when not in use, its gas valve V
4
′ is lifted and closed by the action of a taper cam
2
a
′, which is mounted to the distal end of an ignition operating shaft
2
′ linked integral with an ignition knob
1
′, pressing via a link lever
30
′ together with a diaphragm
15
′ as resisting against the yielding force of an adjusting spring
16
′. The pilot burner governor valve unit PGV′ comprises a diaphragm
15
″, a gas valve V
4
″, and an adjusting spring
16
″.
For starting the ignition, the ignition knob
1
′ is turned from the “stop” position to the “pilot” position and then depressed by one stroke, hence activating the ignition operating shaft
2
′ to push and open the magnetic valve V
1
′ of a safety solenoid valve unit MV′. This allows the gas to run from a gas inlet
5
a
′ via the pilot burner governor valve unit PGV′ mounted across the gas passage to the pilot burner PB′. As the gas is ignited by a match or lighter, a pilot flame c′ is produced thus maintaining the magnetic valve V
1
′ open. At the time, the gas valve V
4
′ of the main burner governor valve unit MGV′ remains closed. Then, the ignition knob
1
′ is released from being pressed and turned further from the “pilot” position to the “open” position. As a result, the lifting and closing of the gas valve V
4
′ of the main burner governor valve unit MGV′ by the taper cam
2
a
′ of the ignition operating shaft
2
′ is canceled. Once the gas valve V
4
′ is freed and open, it then acts as a governor valve in cooperation with the diaphragm
15
′.
Since the magnetic valve V
1
′ serves as a plunger valve, it requires an extra mechanism for being forced to the closing position, which is implemented by a switch S′ provided in an electromagnetic circuit to disconnect the safety solenoid valve unit MV′ from the power supply. Only when the ignition knob
1
′ is turned to the “stop” position, the switch S′ is switched off to close the magnetic valve V
1
′.
When the temperature of hot water in a reservoir A′ is lower than a desired level, the action of a sensor rod B′ drives a snap lever
23
′ to move a snap disk
25
′ to the opposite position, thus opening a snap valve V
5
′ to supply a flow of gas to the main burner. The gas is then ignited by the pilot flame c′ hence increasing the temperature of the hot water in the reservoir A′ to the desired level. As the hot water in the reservoir A′ reaches the desired temperature, it is sensed by the sensor rod B′ which in turn moves back the snap disk
25
′ to the original position (at the standby state) Simultaneously, the snap valve V
5
′ is closed to extinguish the flame of the main burner providing the standby state. Denoted by F′ is a thermal fuse provided in the electromagnetic circuit and
28
′ is a temperature setting screw which supports the proximal end of the snap lever
23
′. Also shown is a pilot filter
31
′.
However, the conventional control valve described above includes the main burner governor valve unit MGV′ and the pilot burner governor valve unit PGV′, incorporating a two-governor system. Therefore, its structure will be complicated and its overall size will hardly be minimized, hence increasing the production cost.
Also, the electromagnetic circuit contains the electric switch S′ and the thermal fuse F′, permitting the resistance to increase with time. As the resistance increases in the electromagnetic circuit, the current will proportionally be declined.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide a control valve for a vessel gas water heater having a single governor provided for controlling the flow of gas for a wider range from pilot supply to main supply thus to eliminate the foregoing problems as of the prior art.
As defined in claim
1
of the present invention for solving the above problems, a control valve for a vessel gas water heater is provided having an ignition knob pressed and turned for opening the magnetic valve and igniting the pilot burner, the magnetic valve maintained open by the electromotive force of a thermocouple heated with a pilot flame, and then, the ignition knob released from being pressed and turned further for opening the plunger valve to enable the supply of gas to the main burner, and having a sensor rod for contracting and expanding depending on the temperature of hot water in a reservoir to open and close the snap valve and thus proceed and cancel the combustion in the main burner for automatically controlling the temperature of the hot water in the reservoir to a desired level, characterized by a single governor valve unit arranged in that the positional relationship between its valve and valve seat is correctly maintained to have a wide range of the flow of gas from a pilot supply to a main supply, thus enabling stable control over both the flow of gas to the main burner and the flow of gas to the pilot burner.
As defined in claim
2
of the present invention, the control valve for a vessel gas water heater according to claim
1
may be modified in which the governor valve is also arranged in that the interfacial accuracy between the valve and the valve seat is improved and the valve is prevented from tilting.
As defined in claim
3
of the present invention, the control valve for a vessel gas water heater according to any of claims
1
and
2
may be modified in which the valve seat for the valve is increased in the seating tightness using a rubber molding and fine polishing.
As defined in claim
4
of the present invention, the control valve for a vessel gas water heater according to any of claims
1
and
2
may be modified in which the valve is prevented from tilting by a guide pin freely fitted in a shaft of the valve.
As defined in claim
5
of the present invention, the control valve for a vessel gas water heater according to claim
1
may be modified in which the pilot burner is a constantly flaming type pilot burner designed for also heating a thermocouple.
The control valve for a vessel gas water heater defined in claim
1
of the present invention, which is arranged in that the ignition knob is pressed and turned for opening the magnetic valve and igniting the pilot burner, the magnetic valve is maintained open by the electromotive force of the thermocouple heated with the pilot flame, and then the ignition knob is released from being pressed, and turned further for opening the plunger valve to enable the supply of gas to the main burner and thus set the standby state while the sensor rod is provided for contracting and expanding depending on the temperature of hot water in the reservoir to open and close the snap valve and thus proceed and cancel the combustion in the main burner for automatically controlling the temperature of the hot water in the reservoir to a desired level, is characterized by the single governor valve unit arranged in that the positional relationship between its valve and valve seat is correctly maintained so that the supply of the gas is constantly flown corresponding to the requirement for the pilot supply and the main supply which ranges widely from the pilot supply to the main supply. As a result, the con
Inagaki Hideo
Tanahashi Atsushi
Ali Mohammad M.
Paloma Industries Limited
Pearson & Pearson LLP
Tapolcai William E.
LandOfFree
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