Field of the invention
[0001] The present invention relates to a control method of a thermostatic system and, more
particularly, to a control method applicable to a water heater, wherein two electromagnetic
valves are exploited to exactly control gas outflow at the gas outlet. Thereby, thermostatic
control of the water heater can be achieved.
Background of the invention
[0002] As shown in Fig. 1, a gas switch control system 10 is installed in a prior art water
heater. The gas switch control system 10 comprises a gas inlet 11 for inputting gas,
a first gas outlet 12 for outputting gas to a main stove, and a second gas outlet
13 for outputting gas to a pilot flame. A valve 14 is arranged between the gas inlet
11 and the first gas outlet 12 and the second gas outlet 13. The action of the valve
14 is controlled by a water pan 15. When cold water is input from a cold water inlet
16 into the water pan 15, the valve 14 will be pushed open so that gas can be transferred
from the gas inlet 11 to the first gas outlet 12 and the second gas outlet 13.
[0003] A switch middle seat 17 is installed between the first gas outlet 12 and the second
gas outlet 13. The switch middle seat 17 comprises an upper lid 18 and a bottom seat
19, which are assembled to form a hollow shell. A valve sheet 20 made of resilient
material such as rubber is installed in the switch middle seat 17. The valve sheet
20 is fixedly gripped between the upper lid 18 and the bottom seat 19. The valve sheet
20 is connected to a connecting link 21. One end of the connecting link 21 has a valve
22. The valve 22 can be used to control the open or close of the first gas outlet
12.
[0004] The valve sheet 20 partitions the switch middle seat 17 into a first gas room 23
and a second gas room 24. A first electromagnetic valve 25 and a second electromagnetic
valve 26 are installed on the side wall of the second gas room 24. The first electromagnetic
valve 25 is normally open and situated between the first gas room 23 and the second
gas room 24. The first electromagnetic valve 25 can be used to control the open or
close state between the first gas room 23 and the second gas room 24. The second electromagnetic
valve 26 is normally close and situated between the second gas room 24 and the second
gas outlet 13. The second electromagnetic valve 26 can be used to control the open
or close state between the second gas room 24 and the second gas outlet 13, i.e.,
the open or close of the second gas outlet 13.
[0005] When cold water is input from the cold water inlet 16 into the water pan 15, the
valve 14 will be pushed open through the water pan 15. Therefore, gas can be transferred
from the gas inlet 11 into the first gas room 23 of the switch middle seat 17. Gas
can also be transferred via the first electromagnetic valve 25 at open state to the
second gas room 24. At this time, the second electromagnetic valve 26 can be controlled
to be open so that gas can be transferred to the pilot flame via the second gas outlet
13, hence facilitating action of ignition. When the pilot flame has been ignited,
the first electromagnetic valve 25 can be controlled to be close so that gas in the
second gas room 24 will be gradually burned out. At this time, the gas pressure in
the first gas room 23 will be larger than that in the second gas room 24. Therefore,
gas will push the valve sheet 20 to move toward the direction of the second gas room
24. The valve 22 will be jointly moved toward the direction of the switch middle base
17 through the connecting link 21. The first gas outlet 12 can thus be controlled
to be open so that gas can be output via the first gas outlet 12 to the main stove.
[0006] However, in the above gas switch control system 10 of prior art, the first electromagnetic
valve 25 and the second electromagnetic valve 26 can only make a simple on or off
action. Gas outflow of the first gas outlet 12 output to the main stove can not be
exactly controlled so that thermostatic control of the water heater can not be achieved.
Summary and objects of the present invention
[0007] The primary object of the present invention is to provide a control method of a thermostatic
system, wherein two electromagnetic valves of a thermostatic system of a water heater
can be controlled to perform the control of gas charge and discharge of a second gas
room so as to push a valve sheet forwards or backwards. Thereby, gas outflow of a
first gas outlet output to a main stove can be exactly controlled so that linearity
of temperature change of the water heater is more apparent. Thermostatic control of
the water heater can thus be achieved.
[0008] To achieve the above object, the present invention provides a control method of a
thermostatic system. When gas outflow output to a main stove is too large, the first
electromagnetic valve is controlled to be open and the second electromagnetic valve
is controlled to be close. Gas will be transferred from the first gas room to the
second gas room. The control of gas charge of the second gas room is thus performed
so as to decrease the open degree of the first gas outlet used to output gas to the
main stove, hence decreasing gas outflow. When gas outflow output to the main stove
is too small, the first electromagnetic valve is controlled to be close and the second
electromagnetic valve is controlled to be open. Gas can not be transferred to the
second gas room, and gas in the second gas room can be output via the second gas outlet
used to output gas to a pilot flame. The control of gas discharge of the second gas
room is thus performed so as to increase the open degree of the first gas outlet,
hence increasing gas outflow.
[0009] The various objects and advantages of the present invention will be more readily
understood from the following detailed description when read in conjunction with the
appended drawings, in which:
Brief description of drawing:
[0010]
Fig. 1 is a cross-sectional view of a gas switch control system in prior art;
Fig. 2 is a cross-sectional view of the present invention when not used;
Fig. 3 is a cross-sectional view of the present invention when being ignited;
Fig. 4 is a cross-sectional view of the present invention after ignited;
Fig. 5 is a block diagram of the control method of the present invention;
Fig. 6 is a timing diagram of the control method of the present invention.
Detailed description of preferred embodiment
[0011] The present invention relates to a control method of a thermostatic system as shown
in Fig. 2. The present invention is applicable to a thermostatic system 50 of a general
water heater. The thermostatic system 50 is roughly like a gas switch control system
of prior art. The thermostatic system 50 comprises a gas inlet 51 for inputting gas,
a first gas outlet 52 for outputting gas to a main stove, and a second gas outlet
53 for outputting gas to a pilot flame. A valve 54 is arranged between the gas inlet
51 and the first gas outlet 52 and the second gas outlet 53. The action of the valve
54 is controlled by a thimble 551 of a water pan 55. The water pan 55 has a cold water
inlet 56. When cold water is input from the cold water inlet 56 into the water pan
55, the thimble 551 will be jointly moved so that the valve 54 will be pushed open
to let gas be transferred from the gas inlet 51 to the first gas outlet 52 and the
second gas outlet 53.
[0012] A switch middle seat 57 is installed between the first gas outlet 52 and the second
gas outlet 53. The switch middle seat 57 comprises an upper lid 58 and a bottom seat
59, which are assembled to form a hollow shell. A valve sheet 60 made of resilient
material such as rubber is installed in the switch middle seat 57. The valve sheet
60 is fixedly gripped between the upper lid 58 and the bottom seat 59. The valve sheet
60 is connected to a connecting link 61. One end of the connecting link 61 has a valve
62. The valve 62 can be used to control the open or close and the gas flux of the
first gas outlet 52.
[0013] The valve sheet 60 partitions the switch middle seat 57 into a first gas room 63
and a second gas room 64. A first electromagnetic valve 65 and a second electromagnetic
valve 66 are installed on the side wall of the second gas room 64. The first electromagnetic
valve 65 is normally open and situated between the first gas room 63 and the second
gas room 64. The first electromagnetic valve 65 can be used to control the open or
close state between the first gas room 63 and the second gas room 64. The second electromagnetic
valve 66 is normally close and situated between the second gas room 64 and the second
gas outlet 53. The second electromagnetic valve 66 can be used to control the open
or close state between the second gas room 64 and the second gas outlet 53, i.e.,
the open or close of the second gas outlet 53.
[0014] As shown in Fig. 3, when cold water is input from the cold water inlet 56 into the
water pan 55, the valve 54 will be pushed open through the thimble 551 of the water
pan 55. Therefore, gas can be transferred from the gas inlet 51 into the first gas
room 63 of the switch middle seat 57. Gas can also be transferred via the first electromagnetic
valve 65 at open state to the second gas room 64. At this time, the second electromagnetic
valve 26 can be controlled to be open so that gas can be transferred to the pilot
flame via the second gas outlet 53, hence facilitating action of ignition.
[0015] As shown in Fig. 4, when the pilot flame has been ignited, the first electromagnetic
valve 65 can be controlled to be close so that gas in the second gas room 64 will
be gradually burned out. At this time, the gas pressure in the first gas room 63 will
be larger than that in the second gas room 64. Therefore, gas will push the valve
sheet 60 to move toward the direction of the second gas room 64. The valve 62 will
be jointly moved toward the direction of the switch middle base 57 through the connecting
link 61. The first gas outlet 52 can thus be controlled to be open so that gas can
be output via the first gas outlet 52 to the main stove.
[0016] The first electromagnetic valve 65 and the second electromagnetic valve 66 can be
properly controlled in the present invention so that they can not only make a simple
on or off action. As shown in Figs. 5 and 6, when a water temperature sensor detects
the temperature is too high or gas outflow output to a main stove is too large, the
first electromagnetic valve 65 is controlled to be open and the second electromagnetic
valve is controlled to be close. Gas can transferred via the first gas room 63 to
the second gas room 64. The control of gas charge of the second gas room 65 is thus
performed to increase the gas pressure in the second gas room 64 so that the valve
sheet 60 will be pushed to move toward the direction of the first gas room 63. The
valve 62 will be jointly moved toward the direction of the first gas outlet 52 through
the connecting link 61 to decrease the open degree of the first gas outlet 52, hence
decreasing gas outflow output to the main stove. When the water temperature sensor
detects the temperature is too low (insufficient) or gas outflow output to the main
stove is too small, the first electromagnetic valve 65 is controlled to be close and
the second electromagnetic valve 66 is controlled to be open. Therefore, gas can not
be transferred to the second gas room 64, and gas in the second gas room 64 can be
output via the second gas outlet 53. The control of gas discharge of the second gas
room 64 is thus performed to let the gas pressure in the second gas room 64 decrease
so that the gas pressure in the first gas room 63 will be larger than that in the
second gas room 64. The valve sheet 60 will be pushed to move toward the direction
of the second gas room 64. The valve 62 will be jointly moved toward the opposite
direction of the first gas outlet 52 through the connecting link 61 to increase the
open degree of the first gas outlet52, hence increasing gas outflow output to the
main stove. When water is kept at a proper temperature, the first electromagnetic
valve 65 and second electromagnetic valve 66 are controlled to be close.
[0017] To sum up, the control of gas charge and discharge of the second gas room 64 can
be performed by controlling the two electromagnetic valves 65 and 66. The valve sheet
66 can be pushed to move forwards or backwards so that gas outflow of the first gas
outlet 52 output to the main stove can be exactly controlled. Thermostatic control
of the water heater can thus be achieved.
[0018] Although the present invention has been described with reference to the preferred
embodiments thereof, it will be understood that the invention is not limited to the
details thereof. Various substitutions and modifications have been suggested in the
foregoing description, and others will occur to those of ordinary skill in the art.
Therefore, all such substitutions and modifications are intended to be embraced within
the scope of the invention as defined in the appended claims.