JP3253893B2 - Submersible type water level sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for controlling a pump at a constant speed irrespective of water depth by performing a variable speed operation of a pump by measuring a water depth such as a water level of a sewage treatment tank. The present invention relates to a submerged hydraulic pressure level sensor used for purposes such as generating an alarm when the water level reaches a certain level.

[0002]

2. Description of the Related Art The submerged water pressure type water level sensor includes:
For example, the one shown in FIG. 3 is generally known. This is a sensor in which a water level detecting element 5 is housed and fixed by a nut 6 using a screw provided in a part of a member constituting the water level detecting element 5 inside a housing 4 including an upper housing 2 and a lower housing 3. The main body 1 and the sensor main body 1
And a cable 7 for taking out signals extending outward from the upper end of the power supply.

The upper housing 2 is formed in a smooth conical shape so that even if foreign matter floating on the water surface becomes entangled with the foreign matter, the foreign matter easily falls off as the water surface is lowered. A water level detecting element 5 is provided immediately below the lower housing 3.
A lower cover 8 is attached to protect the pressure-sensitive part from contacting foreign objects directly or applying external force. Further, a weight 9 for imparting stability to migration of water surface and inflow of water is incorporated in the housing 4.

On the other hand, a plurality of conductors 10 and an air tube 11 made of, for example, polyethylene for introducing atmospheric pressure into the inside of the sensor main body 1 are integrally incorporated in the cable 7.

Here, in the case of, for example, a manhole pump device, a large amount of sewage often flows into a narrow water tank, and the sewage in the manhole vibrates violently due to the inflow, so that the input sensor body swings. The indicated value may fluctuate. Therefore, as described above, the weight 9
The stabilization of the sensor body 1 is intended, but in the case of a wave or a high flow velocity, it is necessary to increase the mass of the weight 9, and when the mass is increased in this manner, When a large tension is applied to the cable 7 and vibration due to a wave is applied thereto, the conductor in the conductor 10 incorporated in the cable 7 may be disconnected.

In order to prevent this, as shown in FIG.
A base member 12 is attached to the sensor body 1, and a chain 13 having one end connected to the base member 12 is extended along the cable 7, thereby supporting the mass of the sensor body 1 including the weight 9 with the chain 13, It was performed to prevent tension from being directly applied to 7.

Here, this type of submerged water pressure type water level sensor is generally called a throw-in type, and in an example such as a manhole pump device for relay transportation of sewage, a pump is installed in a narrow manhole. After that, they are suspended from above.

[0008]

However, in the above-mentioned conventional submerged water pressure type water level sensors, all of them have a water level detecting element rigidly connected to a casing or the like and housed and fixed in the casing. And for this, for example,
In cases such as the above-mentioned manhole pump device, when the pump is installed and suspended from above after installation, there is a case where the sensor body is accidentally dropped on the concrete floor surface due to erroneous handling. In such a case, a large impact is applied to the water level detecting element, which may lead to this damage.

Further, if a chain is provided and the mass of the sensor main body including the weight is supported by the chain, the cost as a product is increased accordingly.

The present invention has been made in view of the above circumstances, and when the sensor body is installed, even if the handling is mistakenly dropped on the concrete floor, the water level detecting element is damaged. A submerged hydraulic water level that prevents the conductor inside the cable from being broken due to direct tension acting on the conductor inside the cable without increasing the cost. It is intended to provide a sensor.

[0011]

According to the present invention, there is provided a submerged hydraulic pressure level sensor in which a weight is added to a sensor body and a water level detecting element is accommodated in a housing. The detection element is elastically held via an elastic member.

Thus, even if an impact force acts on the sensor body due to a fall or the like, the impact force is absorbed by the elastic member, and the impact force at this time is prevented from being directly transmitted to the water level detecting element. can do.

[0013] Another submerged hydraulic pressure level sensor of the present invention is:
In a submerged hydraulic pressure level sensor in which a weight is added to a sensor main body and a water level detecting element is housed in a housing, the cable extending from the sensor main body includes a cable extending by the sensor main body including the weight. And a power string for supporting a tension acting on the wire.

Thus, the tension acting on the cable due to the mass or the like of the water level sensor including the weight is supported by the force cord, and the mass or the like is prevented from directly acting on the conductor in the cable. Disconnection of the conductor can be prevented.

[0015]

FIG. 1 is a block diagram showing an embodiment of the present invention.
A description will be given based on FIG. As shown in FIG. 1, the sensor main body 20 includes a housing 23 including a substantially cylindrical upper housing 21 and a lower housing 22.
The housing 23 is configured by screwing the upper inner peripheral surface of the lower housing 22 to the lower outer peripheral surface of the upper housing 21.

A step 21a is provided at a predetermined position on the inner peripheral surface of the upper housing 21, and a step 22a is provided at a predetermined position on the inner peripheral surface of the lower housing 22, respectively. A substantially cylindrical sensor case 24 is fixedly accommodated in a housing 23 in a state where the outer peripheral surface is surrounded by 21 and both upper and lower end surfaces are sandwiched by both step portions 21a and 22a. Here, an O-ring 25 as a seal member is interposed between the upper end of the sensor case 24 and the inner peripheral surface of the upper housing 21.

An inflated portion 26 is provided at the lower portion of the sensor case 24, and a concave groove 26a is formed on the upper surface of the inflated portion 26. The base of the mounting member 27 bent inward in a hook shape is embedded.

An O-ring 28 serving as an elastic member also serving as a sealing material is accommodated in the concave groove 26a, and a water level detecting element 29 is mounted thereon, and this is mounted on the sensor case 24.
After being accommodated in the sensor case 24, the O
An O-ring 30 similar to the ring 28 is placed, and the two O-rings 28, 30 are compressed via the hollow disk-shaped mounting plate 31 and the mounting member 27 disposed on the O-ring 30, The water level detection element 29 is fixed. A circuit board 32 that converts a signal from the water level detection element 29 into, for example, a current signal and outputs the signal, on the mounting plate 31.
Is fixed.

Here, the depth of the concave groove 26a is
When the water level detecting element 29 is fixed as described above so as to be smaller than the thickness of the ring 28 after compression,
Upper surface of bulging portion 26 of sensor case 24 and water level detecting element 2
9 is set such that a gap δ is formed between the lower surface of the base 9 and the lower surface of the base 9.

The sensor case 24 has excellent mechanical strength and corrosion resistance, and also has excellent impact strength.
For example, it is made of vinylidene fluoride resin,
It also has a function of absorbing the applied impact and reducing the impact on the circuit board 32 and other structural members.

A substantially cylindrical weight 33 for providing stability against migration of water surface and inflow of water is connected to a lower end of the lower casing 21 via a bolt 34.

According to the sensor body 20 configured as described above, the impact force generated by dropping or the like is transmitted from the weight 33 to the lower housing 22, and further transmitted to the sensor case 24 and the upper housing 21. However, the water level detecting element 2
9 is not in direct contact with the upper housing 21, the lower housing 22, and the sensor case 24, and O
Since they are held floating from these components via the rings 28 and 30, only a small force attenuated by the O-rings 28 and 30 is applied. Thereby, the water level detecting element 29 can be protected from the impact force.

At the upper part of the sensor body 20, an end of a cable 40 is inserted and a sealing and fixing agent 41 such as epoxy resin is attached.
Is fixed inside the sensor body 20 by
It is irremovably connected via a holding member 42 and a socket 43. FIG. 2 shows a cross section of the cable 40.

As shown in FIG. 1, the cable 40 includes a sheath 44, a shield 45, a conductor 46, a polyethylene tube 47, and a power cord 48. These polyethylene tube 47 and conducting wire 46 together with power cord 48,
It is arranged to extend in the longitudinal direction of the cable 40.

As shown in FIG. 1, the ends of the power cords 48 are embedded and fixed inside the sealing and fixing agent 41, and have relatively small elongation and high tensile strength. It is constituted by. Thereby, the tension applied to the cable 40 is directly transmitted to the force string 48 having relatively small elongation and high tensile strength, instead of the conducting wire 46 and the polyethylene tube 47. Here, the polyethylene tube 47 is used as an air tube for introducing atmospheric pressure into the sensor main body 20.

As described above, the tension acting on the cable 40 is supported by the force string 48 incorporated in the cable 40, so that excessive tension is prevented from acting on the conductor 46, and the internal conductor 49 can be prevented, and can be manufactured at a lower cost than using a chain or the like.

The aramid fiber is excellent in flexibility, and by forming the power string 48 with the aramid fiber,
The flexibility of the cable 40 is not impaired, and the handleability when installing a water level sensor is not impaired.

[0028]

As described above, according to the present invention, even when the sensor body is accidentally dropped into the manhole during the mounting operation, the shock applied to the water level detecting element is significantly reduced. The water level detecting element can be prevented from being damaged. In addition, depending on the water tank in which the water level sensor is installed, there may be intense ripples or water currents.In such a case, it is necessary to attach a heavy weight to stabilize the sensor body. Even in this case, it is possible to prevent a tension from directly acting on the conductor in the cable without increasing the cost, thereby preventing the conductor in the conductor from being disconnected.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a submerged hydraulic pressure level sensor according to the present invention.

FIG. 2 is an enlarged sectional view taken along line AA of FIG. 1 (an enlarged sectional view of a cable).

FIG. 3 is a sectional view showing a conventional example.

FIG. 4 is a side view showing another conventional example.

[Explanation of symbols]

 Reference Signs List 20 sensor main body 23 housing 24 sensor case 28, 30 O-ring (elastic member) 29 water level detecting element 32 circuit board 33 weight 40 cable 46 conductive wire 47 polyethylene tube (air tube) 48 power string 49 conductor

Claims (2)

(57) [Claims] 1. A weight is added to a sensor body, and
A submerged hydraulic pressure level sensor in which a water level detection element is housed inside a housing, wherein the water level detection element is vertically moved by a pair of ring-shaped elastic members.
A submerged hydraulic pressure level sensor characterized by being elastically held by being clamped from a direction . 2. A submerged cable according to claim 1, wherein a cable extending from the sensor main body is provided with a force string for supporting a tension acting on the cable by the sensor main body including the weight. Type hydraulic water level sensor.