BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] This invention is related to a proportional control gas valve that is capable of
linearly controlling a relatively large range of gas flow while utilizing a very small
amount of energy. Furthermore, it has a fail-safe mode of operation.
2. Description of the Prior Art
[0002] One of the conventional ways to control the flow rate of gas fuel is accomplished
by having a number of gas burners present within a heating apparatus. When little
heat is required, only some of those gas burners will operate. As more heat is required,
more gas burners will operate within the apparatus. Another conventional way to control
the flow rate of gas fuel within a heating apparatus is to use several solenoid gas
valves within a burner to control the flow rate of gas fuel. As more heat is needed,
more of the valves within a burner commence operation within the heating apparatus.
[0003] However, while the result of having many gas burners operate simultaneously is an
increase in heat output, the operation of many burners also results in increased cost,
and makes it impossible to control gas flow linearly. Likewise, having a number of
solenoid gas valves operate within a burner increases the costs of heating as more
gas valves are required, and also cannot regulate gas flow linearly.
[0004] The costs of operating a conventional heating apparatus through the use of gas burners
have generally been high because each of the burners require a gas solenoid valve
for operation control. The conventional gas solenoid valve must be controlled manually,
through the use of a switch or the like to control gas flow. However, by this method,
gas flow cannot be controlled linearly.
[0005] Because the conventional gas solenoid valve is unable to control a large range of
gas fuel flow rate, the typical heating apparatus, using the conventional gas solenoid
valve, has a choice of flow rate from between one (1) to five (5) minimum heat to
maximum heat range settings. This is a limited range of heat settings, reflecting
the inability of the conventional gas solenoid valve to regulate a large range of
gas fuel flow.
[0006] The small range of gas fuel flow provided by the gas solenoid valve has a number
of disadvantages. One disadvantage is that the gas solenoid valve cannot meet the
needs of heat users requiring heat at a precise temperature. Another disadvantage
is that the small gas fuel flow range can waste energy, as heat users may be forced
to utilize a higher heat setting than required because of the limited range of heat
settings provided through the use of the conventional gas solenoid valve.
[0007] Furthermore, the conventional gas solenoid valve is very complicated in structure
and requires a considerable amount of energy for operation. The conventional gas solenoid
valve generally includes a magnetic circuit formed with a fixed iron core, magnets
and a magnetic member. A coil holder is movably provided with respect to the outer
periphery of the fixed iron core and has a magnetic coil wound around itself. A sleeve
is accommodated within the magnets and spaced apart from the outer periphery of the
fixed iron core for a determined distance. An actuating portion is formed with the
fixed iron core. Therefore, it can be seen that the conventional gas solenoid valve
is complex in structure.
[0008] Furthermore, should the fire igniting the gas fuel within a heating apparatus stop
of its own accord, without being manually turned off, the conventional gas solenoid
valve is not equipped to halt the gas fuel flow. Thus the gas fuel will flow at the
rate set by the manual switch heat range setting, until the heating apparatus is manually
switched off. This is a potentially very dangerous situation.
[0009] Thus, it is an object of the present invention to provide an improved proportional
control gas valve which can obviate and mitigate the abovementioned drawbacks.
SUMMARY OF THE INVENTION
[0010] This invention is related to a proportional control gas valve that is capable of
linearly controlling a relatively large range of gas flow while utilizing a very small
amount of energy and has a fail-safe mode of operation.
[0011] According to a preferred embodiment of the present invention, a proportional control
gas valve includes a valve body formed with an inlet having a first orifice, a first
chamber communication with the inlet through the orifice, a second chamber formed
with a balancing orifice and a second orifice, a third chamber in communication with
the first chamber through the balancing orifice, a fourth chamber in communication
with the first chamber via the second orifice, a fifth chamber in communication with
the fourth chamber, and an outlet in communication with the fifth chamber, a solenoid
assembly mounted in the first chamber for controlling gas flowing from the first chamber
to the fourth chamber via the second orifice, a main diaphragm arranged between the
inlet and the third chamber, a valve spring mounted under the main diaphragm and urging
the main diaphragm to move upwardly to close a passage from the inlet to the third
chamber, a regulation diaphragm mounted inside the fifth chamber, a regulation spring
mounted on the regulation diaphragm, an adjust stem connected with the regulation
diaphragm for controlling gas flow rate from the fourth chamber to the outlet, and
a servomotor drivingly connected with the adjust stem, whereby the proportional control
gas valve only requires a small amount of energy to control the gas pressure and flow
rate simultaneously.
[0012] It is an object of the present invention to provide a proportional control gas valve
which can control the gas pressure and flow rate simultaneously.
[0013] It is still another object of the present invention to provide a proportional control
gas valve which can be accurately controlled by a servomotor through feedback means
without hysteresis.
[0014] It is still another object of the present invention to provide a proportional control
gas valve which can be linearly controlled.
[0015] It is still another object of the present invention to provide a proportional control
gas valve which can be easily converted from a proportional valve to a regulation
valve.
[0016] It is still another object of the present invention to provide a proportional control
gas valve which can be controlled by fuzzy logic technique.
[0017] It is still another object of the present invention to provide a proportional control
gas valve which is simple in construction and easy to manufacture.
[0018] It is still another object of the present invention to provide a proportional control
gas valve which is facile to maintain.
[0019] The foregoing objects and summary provide only a brief introduction to the present
invention. To fully appreciate these and other objects of the present invention as
well as the invention itself, all of which will become apparent to those skilled in
the art, the following detailed description of the invention and the claims should
be read in conjunction with the accompanying drawings. Throughout the specification
and drawings identical reference numerals refer to identical or similar parts. Many
other advantages and features of the present invention will become manifest to those
versed in the art upon making reference to the detailed description and the accompanying
sheets of drawings in which a preferred structural embodiment incorporating the principles
of the present invention is shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
FIG. 1 is a schematic view illustrating the working principle of the present invention;
FIG. 2 is a cross sectional view of the present invention;
FIG. 3 is a top view of the present invention;
FIG. 4 is a longitudinal sectional view of the present invention; and
FIG. 5 is a sectional view taken along line A-A of FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] For the purpose of promoting an understanding of the principles of the invention,
reference will now be made to the embodiment illustrated in the drawings. Specific
language will be used to describe same. It will, nevertheless, be understood that
no limitation of the scope of the invention is thereby intended, such alterations
and further modifications in the illustrated device, and such further applications
of the principles of the invention as illustrated herein being contemplated as would
normally occur to one skilled in the art to which the invention relates.
[0022] With reference to FIGS. 1 through 5, the proportional control gas valve according
to the present invention generally comprises a valve body 1, a main diaphragm 3, a
valve spring 5, a solenoid assembly 10, a regulation diaphragm 16, an adjust stem
17, a regulator spring 19, a first gear 23, a second gear 24, and a servomotor 25.
The valve body 1 is provided with a valve cover 2 at the bottom and formed with an
inlet 151 at one end, an outlet 161 at another end, a first chamber 101, a second
chamber 102, a third chamber 103, a fourth chamber 104 and a fifth chamber 105. The
inlet 151 has an orifice 1511 in communication with the first chamber 101 which has
a balancing orifice 71 and is provided with a solenoid assembly 10. An orifice 81
is formed between the first chamber 101 and the fourth chamber 104. The solenoid assembly
10 is used for controlling gas flowing out of the first chamber 101 into the fourth
chamber 104. The balancing orifice 71 is in communication with the second chamber
102 which is in turn communicated with the third chamber 103. The main diaphragm 3
is provided at the bottom side with a diaphragm plate 4 and arranged between the outlet
151 and the third chamber 103 and urged by the valve spring 5 to go upwardly against
the passage between the inlet 151 and the third passage 103. The secondary diaphragm
16 is arranged within the fifth chamber 105 and urged by a regulator spring 19 to
move away from a motor screw 24. The secondary diaphragm 16 is provided with a valve
element 17 which is installed between the fourth chamber 104 and the fifth chamber
105. The fifth chamber 105 is in communication with the outlet 161. The servomotor
25 is provided with a crank (not shown) which can be rotated with respect to the servomotor
25. The servomotor may be of any conventional design well known to the art and is
not considered a part of the invention.
[0023] When the solenoid assembly is moved downwardly to close the orifice 81, the gas pressure
applied to both sides of the main diaphragm 3 are equal and the main diaphragm 3 will
be kept closed so that no gas will be able to flow through the gas valve according
to the present invention.
[0024] When the solenoid assembly 10 is moved upwardly to open the orifice 81, the gas will
firs flow through the orifice 1511 into the first chamber 101 and then will be divided
into two branch streams which will flow through the balancing orifice 71 and the orifice
81 into the second chamber 102 and the fourth chamber 104 respectively. Thereafter,
one of the two branch streams will flow into the third chamber 103 to apply pressure
on the bottom of the main diaphragm 3. However, as the main gas flow from the inlet
151 is divided into two branch streams, the pressure of each of the two branch streams
will be lower than that the main gas flow so that the main diaphragm 3 will be pushed
open by the main gas flow thereby enabling the main gas flow to go to the outlet 161.
As soon as the main diaphragm 3 is opened, the outlet pressure will be sensed by the
regulation diaphragm 16 via a feedback potentiometer 80 or a pressure sensor 90 at
the outlet 161. In the meantime, the other branch stream will flow through the adjust
stem 17 which is controlled by the regulator spring 19. The servomotor 25 is drivingly
connected to the gear 23 which is meshed with the gear 22 which is in turn connected
with a motor screw 24 arranged on the top of the regulator spring 19, so that when
the servomotor 25 is turned on, the gears 22 and 23 will be rotated to drive the adjust
screw 20 to change the tension of the regulator spring 19 thereby accomplishing the
purpose of controlling the pressure and flow rate of the gas flowing out of the outlet
161. The servomotor 25 is controlled by the controller 26 which compares the outlet
pressure with a preset value so that when the outlet pressure is not equal to the
preset pressure, the servomotor 25 will be driven to adjust the position of the adjust
stem 17 thereby maintaining a constant outlet pressure regardless of inlet pressure
variations. When the outlet pressure is equal to the preset pressure, the power supplied
to the servomotor 25 will be cut off thus saving the power required for the operation
of the gas valve. The controller 26 is well known to those having ordinary skill in
the art and will not be described here in detail.
[0025] It will be understood that each of the elements described above, or two or more together
may also find a useful application in other types of methods differing from the type
described above.
[0026] While certain novel features of this invention have been shown and described and
are pointed out in the annexed claim, it is not intended to be limited to the details
above, since it will be understood that various omissions, modifications, substitutions
and changes in the forms and details of the device illustrated and in its operation
can be made by those skilled in the art without departing in any way from the spirit
of the present invention.
1. A proportional control gas valve comprising:
a valve body formed with an inlet having a first orifice, a first chamber communication
with said inlet through said orifice, a second chamber formed with a balancing orifice
and a second orifice, a third chamber in communication with said first chamber through
said balancing orifice, a fourth chamber in communication with said first chamber
via said second orifice, a fifth chamber in communication with said fourth chamber,
and an outlet in communication with said fifth chamber;
a solenoid assembly mounted in said first chamber for controlling gas flowing from
said first chamber to said fourth chamber via said second orifice;
a main diaphragm arranged between said inlet and said third chamber;
a valve spring mounted under said main diaphragm and urging said main diaphragm to
move upwardly to close a passage from said inlet to said third chamber;
a regulation diaphragm mounted inside said fifth chamber;
a regulation spring mounted on said regulation diaphragm;
an adjust stem connected with said regulation diaphragm for controlling gas flow rate
from said fourth chamber to said outlet; and
a servomotor drivingly connected with said adjust stem.
2. The proportional control gas valve as claimed in claim 1, further comprising a controller
for controlling said servomotor.
3. The proportional control gas valve as claimed in claim 1, wherein said servomotor
is drivingly connected with an adjust screw which urges against a top of a regulator
spring.
4. The proportional control gas valve as claimed in claim 1, wherein said solenoid assembly
is configured to be able to close or open said second orifice.
5. The proportional control gas valve as claimed in claim 2, wherein said controller
compares outlet pressure with a preset value so that when said outlet pressure is
not equal to said preset pressure, said servomotor will be driven to adjust position
of said adjust stem so as to maintain a constant outlet pressure regardless of inlet
pressure variations.