JPH0632597Y2 - Pressure detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use and Outline of the Invention] The present invention relates to a pressure detecting device used for detecting the water level in a bathtub, and more particularly, to a portion to be detected by a semiconductor pressure sensor through a liquid pressure medium. The present invention relates to a pressure detection device of the type that detects the pressure of the. Further, in this type of pressure detection device, it is difficult to cause leakage from the storage chamber accommodating the pressure medium or replacement of the detected portion with the liquid, and therefore, a plurality of pressure mediums independently provided. The storage chambers are connected in series by a small passage.

[Prior Art and its Problems] As a pressure detection device for detecting the water level in a bathtub
There is a type disclosed in Japanese Patent No. 5135, in which a detection section (21) of a semiconductor pressure sensor (2) is provided on the side wall of a storage chamber (11) for storing a pressure medium, as shown in FIG. The connection port (12) facing the storage chamber (11) and connected to the storage chamber (11)
It is designed to communicate with (A).

In this case, the pressure in the detected part (A) is
(12) is transmitted to the storage chamber (11), the pressure change in the storage chamber (11) matches that of the detected part (A), and the pressure in this storage chamber (11) is detected by the semiconductor pressure sensor (2). The pressure of the detected portion (A) is detected.

Normally, silicone oil is used as the pressure medium (B). Due to the low viscosity of this pressure medium (B),
The pressure medium (B) in 1) easily leaks from the connection port (12) to the detected part (A) side. In other words, the liquid in the detected part (A) and the pressure medium (B) are easily replaced. In order to prevent such inconvenience, in the above-mentioned conventional one, the storage chamber (11) and the connection port are
A spiral intermediate flow path (13) is formed between (12) and
Even with this, the effect of preventing the replacement of the pressure medium (B) with the liquid in the detected portion (A) is insufficient.

The present invention has been made in view of such a point, and "a detection part (21) of a semiconductor pressure sensor (2) faces a side wall of a storage chamber (11) and is connected to the storage chamber (11). In the `` pressure detection device equipped with the mouth (12) '', the liquid in the detected part (A) is less likely to be replaced with the pressure medium (B) in the storage chamber (11), and
The problem is to make pressure detection accuracy stable over a long period of time.

[Technical Means] The technical means of the present invention taken to solve the above-mentioned problem is that "a plurality of storage chambers (11) (11) are independently installed in parallel and each storage chamber (1)
1) The storage chamber (1
1) Connect (11) in series to connect the frontmost storage chamber (11) and connection port
The (12) and the (12) are communicated with each other through a narrow passageway (15), and the detection section (21) of the semiconductor pressure sensor (2) is exposed to the side wall of the storage chamber (11) at the last position ”.

[Operation] The technical means of the present invention operates as follows.

A plurality of storage chambers (11) (11) are independently arranged, and the capacity of all the storage chambers (11) (11) is set to a required amount.

When pressure is detected by connecting the connection port (12) and the detected part (A), the connection port (12) passage (15) storage chamber (11) passage
(14) The last storage chamber (11) is reached in the path of the storage chamber (11), and the pressure of the detected portion (A) is detected by the detection unit (21) of the semiconductor pressure sensor (2).

The liquid in the detected part (A) enters through the connection port (12) and enters the storage chamber.
To replace the pressure medium (B) in (11), the liquid must
You need to pass (15). Further, the last storage chamber (11) is required to pass through the passages (14) and (14), and the pressure medium (B) in the last storage chamber (11) corresponding to the detection unit (21). Is hardly partially replaced with the liquid in the detected part (A).

[Effects] The present invention having the above-described configuration has the following unique effects.

The liquid in the detected part (A) is the pressure medium (B) in the frontmost storage chamber (11)
Since it is necessary to pass through the passage (15) and move into the storage chamber (11) for replacement, the pressure medium (B) in this portion is less likely to be replaced by the liquid in the detected portion (A). Further, since the pressure medium (B) in the last-most storage chamber (11) to which the detection section (21) corresponds is hardly replaced with the liquid, the pressure detection accuracy is improved.

Also, the pressure medium (B) in the storage chamber (11) (11) during assembly and transportation
There is no worry about leaking out.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In this embodiment, the casing (1) is divided into two chambers, one of which serves as a housing portion for the semiconductor pressure sensor (2) and the other serves as a housing portion for the pressure medium (B). The chamber has a configuration in which a shaft body (3) having three groove portions (31) (32) corresponding to the storage chambers (11) and (11) is inserted into a cylindrical vacant chamber (10).

The shaft body (3) is formed with a flange portion (33) at the base end portion, the tip side of which is configured to have a diameter that fits exactly into the cylindrical cavity (10), and an annular groove portion (31) on its outer peripheral surface. ) (31) and groove (32)
Are formed. These grooves are arranged at regular intervals, and between the grooves (31) and (31) and between the grooves (31) and (31), there is an oblique direction from the vicinity of the open end of one groove to the vicinity of the bottom of the other groove. The passage (14) is formed, and the passage (15) is formed so as to penetrate between the side wall of the foremost groove (31) and the end surface of the shaft body (3).

The shaft body (3) having the above-mentioned configuration is inserted from the open end of the cylindrical vacant chamber (10), and is fixed to the side wall of the casing (1) by screwing with the flange portion (33). As described above, the annular chamber surrounded by the wall of the columnar chamber (10) and the grooves (31) (32) serves as the storage chambers (11) (11).

In addition, O-rings (34) and (34) are provided on the outer peripheral portion of the shaft body (3) between the groove portions and at both ends of the mouth forming area, and between the O-rings (34) and (34) and the constituent wall of the cylindrical cavity. , Thereby, each of the storage chambers (11)
Will be independent. Further, a part of the cylindrical void (10) becomes a water chamber (16) communicating with the connection port (12) formed on one side of the casing (1) and is located on the tip side of the shaft (3).

A semiconductor pressure sensor is installed on the wall surface facing the last groove (32).
The detection part (21) of (2) is exposed.
The pressure of the detected part (A) connected to (12) is detected.

The pressure medium (B) is accommodated in the three storage chambers (11) (11) configured as described above, but in this embodiment, the capacity of the last storage chamber (11) is maximized. It is set. Therefore, the storage chamber that is the most difficult to replace with the liquid in the detected part (A)
The capacity of (11) becomes the maximum, and from this point, the pressure detection accuracy of the above embodiment is improved.

In addition, even if the size of the last storage chamber (11) is made to match that of the other storage chambers, or slightly smaller than that,
The effect of the present invention is the same.

Further, in the above embodiment, the size of the passages (14) and (15) needs to be set to a diameter of 0.8 mm or more, and preferably the diameter is set to about 1.0 mm to 1.8 mm. When the diameter of the passages (14) and (15) is smaller than 0.8 mm, the accuracy of the detected pressure is lowered due to the influence of the surface tension.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a sectional view taken along line XX, and FIG. 3 is an explanatory view of a conventional example. In the figure, (11) ... Reservoir (2) ... Semiconductor Pressure sensor (21) …… Detector (12) …… Connection port (14) …… Passage (15) …… Passage

Claims (1)

[Scope of utility model registration request] 1. A semiconductor pressure sensor (2) on the side wall of the storage chamber (11).
In the pressure detecting device facing the detection part (21) of (1) and having a connection port (12) communicating with the storage chamber (11), a plurality of storage chambers (11) and (11) are independently arranged side by side. , The storage chambers (11) are communicated with each other through a narrow passageway (14) to communicate the storage chambers (11) (11) in series, and the frontmost storage chamber (11) and the connection port (12) are narrowed. A pressure detection device in which a passage (15) communicates with the detection part (21) of the semiconductor pressure sensor (2) facing the side wall of the last-most storage chamber (11).