JP2002148096A - Pressure sensor and water level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor which can detect the pressure accurately with no restriction on the installing position in the casing, and a water level detector in which pressure variation in the casing causes no measurement error. SOLUTION: In order to suppress back pressure variation in a pressure sensor (74) caused by pressure variation in the casing (4) of the pressure sensor, back pressure at the sensor section (114) is opened to the outside of the casing. Consequently, the effect of pressure variation in the casing is avoided and measurement error of pressure detection or water level detection is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor and a water level detecting device used for detecting a water level change such as a bathtub water level and monitoring the water level.

[0002]

2. Description of the Related Art Conventionally, in a fully automatic bath water heater in which hot water supply and reheating of bath water are automated, a pressure sensor installed in a bath water heater casing is used for detecting a bath water level. The detection accuracy of the pressure sensor that has been used for water level detection is 10 m for the purpose of keeping the bathtub water level at a constant level.
A minimum resolution of about m is used. Further, in measuring the body fat percentage using bath water, a minimum resolution capable of detecting a water level difference of 0.5 mm or less is required because it is necessary to accurately measure the body volume.

[0003]

By the way, the casing of the bath water heater in which the pressure sensor is installed is provided with a device for causing an internal pressure fluctuation in the casing, such as a combustion air supply fan rotated at a high speed by a motor. I have. For example, when the air supply fan rotates, a negative pressure of about several millimeters is generated in the casing, and the negative pressure forms a back pressure of the pressure sensor. As a result, the pressure sensor detects as if a water level rise occurred. An output occurs, and this detection error causes a bad influence on the water level control and the measurement of the body fat percentage.

[0004] To avoid such inconveniences, the position of the pressure sensor may be devised, for example, by installing a pressure sensor outside the casing, or the negative pressure generated when the air supply fan rotates may be measured in advance. There is a method of correcting the output value of the pressure sensor by the negative pressure when the motor rotates. However, in the former, there are restrictions on the installation position of the pressure sensor and restrictions on the arrangement relationship with other devices, and in the latter, although there is no such restriction as the former, the air supply filter of the air supply port of the casing is closed. Also in this case, since the output value of the pressure sensor fluctuates, the relationship between the rotation speed of the fan motor and the negative pressure shifts, and accurate pressure detection, that is, water level detection cannot be performed.

Accordingly, the present invention provides a pressure sensor capable of accurately detecting pressure without being restricted by the installation position in a casing, and a water level detection device which does not cause a measurement error due to an internal pressure fluctuation in the casing. The task is to provide

[0006]

SUMMARY OF THE INVENTION A pressure sensor or a water level detecting device according to the present invention is a sensor for suppressing a back pressure change occurring in a pressure sensor due to an internal pressure fluctuation of a casing (4) in which a pressure sensor (74) is installed. The back pressure of the portion (114) is released to the outside of the casing to avoid the influence of fluctuations in the internal pressure of the casing, and suppresses measurement errors in pressure detection or water level detection.

A pressure sensor according to the present invention is a pressure sensor installed in a casing (4) with a fluctuation in internal pressure, wherein a back pressure of a sensor section (114) is released outside the casing. . That is, by releasing the back pressure of the sensor unit to the outside of the casing, the influence of the pressure fluctuation in the casing can be avoided, and the detection accuracy can be improved.

A pressure sensor according to the present invention is a pressure sensor (74) installed in a casing (4) having an internal pressure fluctuation, wherein a back pressure of a sensor section (114) is supplied to the outside of the casing via a pipe (84). It is characterized by being open to the public. That is, by releasing the back pressure of the sensor unit to the outside of the casing through the pipe, the influence of the pressure fluctuation in the casing can be avoided, and the detection accuracy can be improved.

The water level detecting device of the present invention includes a pipe (for example, a return pipe 6) connected to a water reservoir (for example, bathtub 2).
0), a pressure sensor (74) for detecting water pressure, a casing (4) in which the pressure sensor is installed, and a pipe (8) for releasing the back pressure of the pressure sensor to the outside of the casing.
4) wherein the water level in the container is detected by the pressure sensor. By releasing the back pressure of the sensor unit to the outside of the casing through the pipe, the influence of the pressure fluctuation in the casing can be avoided, and the accuracy of detecting the water level by the pressure can be increased.

In the water level detecting device according to the present invention, the container is a bathtub (2). That is, the pressure sensor is installed in the casing of the hot water supply device, and the detection accuracy of bathtub water can be increased without being affected by the fluctuation of the internal pressure in the casing, so that highly accurate water level control and the like can be realized.

In the water level detecting device of the present invention, the end of the pipe is disposed on the exhaust means (exhaust ports 18 and 20) side,
The back pressure of the pressure sensor is released to the outside air. That is, even if the back pressure of the pressure sensor is released to the outside air through the exhaust means, the back pressure change can be suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention and embodiments thereof will be described below in detail with reference to embodiments shown in the drawings.

FIG. 1 shows a bath water heater which is an embodiment of a pressure sensor and a water level detecting device according to the present invention. The bath water heater forms a hot water supply system that heats the clean water W to supply hot water HW to the bathtub 2 and the like and reheats (additionally heats) the bathtub water BW. Inside the casing 4 of the bath water heater, a divided combustion chamber 6 for burning the fuel gas G is provided. The combustion chamber 6 is provided with burners 8, 10, a hot water supply heat exchanger 12, and a bath heat exchanger 14, and a combustion air supply fan 16 below the lower part and a flue 17 above the upper part. An exhaust port 18, which is an exhaust means via
20 are provided. That is, the combustion air supply fan 16, the burners 8, 10, etc. installed inside the casing 4 draw outside air into the combustion chamber 6 by rotation or combustion, and thus cause internal pressure fluctuation inside the casing 4. In this embodiment, the bathtub 2 is illustrated as a container because it is a bath water heater. However, as a target for detecting the water level by pressure, a container other than the bathtub 2 for storing water may be provided. It is not limited to a bathtub.

A fuel valve 22 for supplying a fuel gas G to the burners 8, 10 is provided with a main valve 24, a proportional valve 26, an on-off valve 28 on the burner 8 side and a proportional valve 30 on the burner 10 side. , An on-off valve 32 and the like are provided to supply or cut off the supply of the fuel gas G, adjust the supply amount, and the like. As means for igniting the burners 8, 10, ignition plugs 34, 36, an igniter 38 and the like are provided.

The hot water supply heat exchanger 12 has a water supply pipe 40 connected to the inlet side and a hot water supply pipe 42 connected to the outlet side thereof.
Is heated by the heat exchanger 12, the hot water HW is supplied through the hot water supply pipe 42. The water supply pipe 40 is provided with a water amount sensor 44, an incoming water temperature sensor 46, and the like.
A tap water temperature sensor 48, a water control valve 50, and the like are provided on the second side, and a bypass pipe 52 is provided between the water supply pipe 40 and the hot water supply pipe 42.
And an electromagnetic valve 54. Hot water HW is supplied to a return pipe 60 of a circulation path 58 on the bathtub 2 side from a bath hot water supply pipe 56 branched from the hot water supply pipe 42. A hot water supply pipe 56 is provided with a pouring solenoid valve 62, a check valve 64, a pouring amount sensor 66, and the like.

A circulation path 58 is formed by a forward pipe 70 and a return pipe 60 between a circulation tool 68 attached to the bathtub 2 and the bath heat exchanger 14, and a pressure feed means is provided on the return pipe 60 side. A pump 72, a pressure sensor 74 as means for detecting the level of the bathtub water BW, a temperature sensor 76 for detecting the temperature of the circulating bathtub water BW, a water flow switch 78 for detecting the presence or absence of circulating water, and the like are provided. A bypass pipe 82 having a bypass valve 80 is provided between the forward pipe 70 and the return pipe 60. And the pressure sensor 74 includes:
A conduit 84 that connects the back pressure of the sensor unit 114 (FIG. 2) to the atmosphere outside the casing 4 is connected, and the open end thereof is guided outside the casing 4.

An electric board 86 is installed inside the casing 4 as control means for receiving necessary detection outputs from various sensors and performing necessary control. The electric board 86 is supplied with AC power. .

The pressure sensor 74 communicates with the bathtub water BW in the bathtub 2 through the return pipe 60, and is means for detecting a pressure corresponding to the water level of the bathtub water BW. For example, as shown in FIG. The sensor is attached with an attachment 88 as a sensor attachment member inserted in the middle of the return pipe 60. The attachment 88 includes connecting pipes 90 and 92 and a pressure guiding pipe 94 connected to the return pipe 60, and the connecting pipes 90 and 92 and the return pipe 60 have O-rings 96 and 98 as watertight members interposed therebetween. At the same time, they are tightly joined by locking members 100 and 102 as fixing means.

The sensor frame 106 of the pressure sensor 74 is fixed to the flange portion 104 of the pressure guiding tube portion 94 with a plurality of screws 108 as fixing means.
4, a cylindrical portion 110 of the sensor frame 106 is inserted, and O is a watertight member fitted to the cylindrical portion 110 side.
The ring 112 makes the pressure guiding tube portion 94 and the sensor frame 1
06 is tightly bonded.

A sensor section 114 is provided on the cylindrical section 110 of the sensor frame 106. That is, the cylindrical portion 110
An annular support 116 made of glass or the like is installed in the center concave portion of the sensor element 118, and a sensor element 118 made of a silicon chip is arranged.
A silicon gel 120 is provided as a pressure-guiding material covering 16. An air layer 1 is provided on the lower surface side of the silicon gel 120.
22 is formed, and the bathtub water BW
Is acting on the pressure receiving surface of the sensor element 118.

Gold wires 124 and 126 as output deriving members are connected to the sensor element 118, and the output is
4, 126. Each gold wire 124, 12
6 are electrically connected to leads 128 and 130, which are output terminals attached through the sensor frame 106.

A projection 132 formed at the center of the outer surface of the sensor frame 106 has a through hole 13
4, and a back pressure port 136 having a diameter larger than the through hole 134 is formed. A pipe 84 that guides the back pressure of the sensor element 118 out of the casing 4 (FIG. 1) is connected to the protrusion 132. This conduit 84 can be composed of, for example, a flexible hose. A cover 142 is provided on the upper surface of the sensor frame 106 to cover the connecting portions between the leads 128 and 130, the protruding portion 132 and the conduit 84, and the conduit 84 is a through hole formed on the ceiling surface of the cover 142. 144.

Next, a control device for controlling the water level in the bathtub 2 based on the output information of various sensors such as the pressure sensor 74 will be described.

For controlling the water level of the bathtub 2, for example, as shown in FIG. 3, a pressure sensor 74, a tap water temperature sensor 48, an incoming water temperature sensor 46, and other sensors 44 and 66 are installed. Each detection circuit 202, 204, 2
06, 208, the A / D converter 210,
After being converted into digital signals by 212, 214 and 216, the digital signals are applied to a CPU 218 which is an arithmetic means. C
The PU 218 has a ROM 220 and a RAM as storage means.
The control output from the CPU 218 is connected to the drive circuits 224, 226, 228, 230, and 23.
2, 234, 236, 238, etc., and the main valve 24,
On-off valves 28, 32, proportional valve 26, spark plugs 34, 3
6. A drive output is applied to the water control valve 50, the pump 72, and the like. Although not shown, other control means such as the proportional valve 30 are controlled by a similar drive circuit. The control unit 200 is provided with a transmission / reception circuit 240 as means for exchanging data with the outside.
The CPU 218 and a remote controller 242 as a remote control unit are connected to each other via a wired or wireless connection. In wireless communication, various signal transmission media such as radio waves and light can be used.

According to such a configuration, bathtub water BW communicates with pressure sensor 74 through return pipe 60, and pressure P corresponding to the water level of bathtub water BW is applied to sensor element 11 of pressure sensor 74.
Acts on 8. An output of the pressure sensor 74, that is, a voltage proportional to the level of the bathtub water BW is generated on the leads 128 and 130.

When the hot water is supplied, the burner 8 is burned, so that the inside of the casing 4 is in a state lower than the atmospheric pressure, that is, a negative pressure state due to the combustion and the supply of air from the supply fan 16. When the inside of the casing 4 changes under such a negative pressure state, when the back pressure of the pressure sensor 74 is released into the casing 4, the influence thereof appears remarkably in the detection output. Since the pressure is released to the atmosphere outside the casing 4, the pressure is not affected by the internal pressure fluctuation inside the casing 4. For this reason, the pressure sensor 74 is connected to the return pipe 6.
Only the water pressure acting through zero can be detected, and the pressure representing the water level can be detected with high accuracy.

The water level detection based on such pressure detection is as follows.
Similarly, the back pressure of the pressure sensor 74 does not fluctuate during the reheating operation in which the burner 10 is burned, so that it can be performed with high accuracy.

Therefore, if the output of the pressure sensor 74 is used, the water level of the bathtub 2 can be accurately controlled at the time of hot water supply, and the water level of the bathtub 2 can be accurately controlled even at the time of fully automatic temperature keeping.

FIG. 4 shows a specific embodiment of a water level detecting device using the pressure sensor of the present invention. In this embodiment, a pressure sensor 74 constituting a water level detecting device is installed on the side of the return pipe 60 built in the casing 4, and a conduit 84 made of a flexible pipe for guiding the back pressure of the pressure sensor 74 to the outside of the casing 4. Are connected to each other, the end of which is guided above the casing 4, and the end of which is open to the outside. According to such a configuration, the back pressure of the pressure sensor 74 is released to the outside air without any limitation on the mounting position of the pressure sensor 74, and the influence of the internal pressure fluctuation in the casing 4 can be reliably avoided. The water level can be detected with high accuracy.

The pipe 84 for guiding the back pressure of the pressure sensor 74 to the outside of the casing 4 may be guided into the flue 17 and discharged to the outside air through the exhaust port 18 or 20, as shown in FIG. Well, and as shown in FIG.
Alternatively, the air may be released from the 20 side to the outside air.

In the embodiment, the conduit 84 is used as a means for guiding the back pressure. However, the conduit 84 can be omitted. For example, as shown in FIG. 7, a pressure detection chamber 243 that avoids internal pressure fluctuation in the casing 4 is formed on the inner surface side of the casing 4 that penetrates the return pipe 60 that is a part of the circulation path 58. The pressure detection chamber 243 has a through hole 244 formed in the casing 4 and is open to the atmosphere. If a pressure sensor 74 as a water level detection device is installed in the pressure detection chamber 243, the back pressure port 136 of the pressure sensor 74
(FIG. 2) can be opened to the atmosphere through the pressure detection chamber 243, and the influence of the internal pressure fluctuation in the casing 4 can be avoided. In this case, the back pressure port 13 of the pressure sensor 74
6 may be connected to a through hole 244 formed in the casing 4 to open to the atmosphere. The same effect can be expected even if the through-hole 144 of the cover 142 of the pressure sensor 74 shown in FIG. 2 is matched with the through-hole 244 of the casing 4 and the back pressure port 136 is opened to the atmosphere through the cover 142.

In the embodiment, the case where the pressure sensor is installed as the bathtub water level detecting device has been described.
The present invention can be applied to any form as long as it is a pressure sensor installed in an enclosed space accompanied by pressure fluctuation, and is not limited to the embodiments.

[0033]

As described above, according to the present invention,
The following effects are obtained. a If a pressure sensor is installed in a casing with fluctuations in internal pressure, the back pressure can be released to the atmosphere or the like through a pipe, so that the pressure detection accuracy is improved without being affected by the fluctuations in internal pressure in the casing. be able to. b Even if a pressure sensor is installed in a casing in which a device that causes an internal pressure fluctuation such as a hot water supply device is built, the accuracy of detecting the water level can be improved. c It is possible to improve the detection accuracy of the bathtub water level and realize high-quality water level control.

[Brief description of the drawings]

FIG. 1 is a piping configuration diagram illustrating a bath water heater that is an embodiment of a pressure sensor and a water level detection device according to the present invention.

FIG. 2 is a longitudinal sectional view showing an embodiment of the pressure sensor of the present invention.

FIG. 3 is a block diagram showing a control device of the bath water heater.

FIG. 4 is a partial sectional view showing a bath water heater which is a specific embodiment of the pressure sensor and the water level detecting device of the present invention.

FIG. 5 is a piping configuration diagram showing a bath water heater which is another embodiment of the pressure sensor and the water level detection device of the present invention.

FIG. 6 is a partial cross-sectional view showing a bath water heater which is another specific embodiment of the pressure sensor and the water level detecting device of the present invention.

FIG. 7 is a partially enlarged view showing another embodiment of the pressure sensor and the water level detecting device of the present invention.

[Explanation of symbols]

 2 Bathtub (container) 4 Casing 18, 20 Exhaust port (exhaust means) 60 Return pipe (pipe) 74 Pressure sensor 84 Pipe 114 Sensor section

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F014 AB02 AC01 BA10 2F055 AA40 BB20 CC02 DD05 EE40 FF38 GG49 HH05 3L024 CC08 DD06 DD17 DD46 GG12

Claims (5)

[Claims] 1. A pressure sensor installed in a casing with an internal pressure fluctuation, wherein a back pressure of a sensor section is released outside the casing. 2. A pressure sensor installed in a casing having an internal pressure fluctuation, wherein a back pressure of a sensor section is opened to the outside of the casing via a pipe. 3. A pressure sensor for detecting a water pressure through a pipe connected to a container for storing water, a casing in which the pressure sensor is installed, and a pipe for releasing a back pressure of the pressure sensor to outside the casing. And a water level detecting device for detecting a water level in the container by the pressure sensor. 4. The water level detecting device according to claim 3, wherein said container is a bathtub. 5. The water level detecting device according to claim 3, wherein an end of the pipe is disposed on an exhaust means side, and a back pressure of the pressure sensor is opened to the outside air.