JPH0382937A - Moisture detector - Google Patents

Abstract

PURPOSE:To make it possible to detect intrusion of water into oil chamber sensitively and stably by providing a water passing container through which only the water that has intruded into the oil chamber is made to pass, and filling the inside of the water passing container with water absorbing swelling material. CONSTITUTION:A motor 6 is driven, and an impeller 7 is rotated through a rotary shaft 8. Then, water is sucked up along the direction of an arrow in a pump 1. At this time, the water intrudes into an oil chamber 11 when there is function deterioration in a sealing device 10. The intruded water passes a water passing container 14 and intrudes into the inside. Pressure difference is generated between the two chambers in the container 14 which is separated with a gage plate 16. The gage plate 16 is elastically deformed by the pressure difference so that the restoring force is balanced with the water separating limiting force. Or the force which deforms the gage plate 16 overcomes the restoring force, and the gate plate 16 undergoes plastic deformation. A gage 17 is also deformed together with the deformation of the gate plate 16. Thus, the intrusion of the water into the oil chamber 11 is detected with a strain gate 17.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a moisture detector that detects water that has entered an oil chamber, and particularly relates to a moisture detector that can detect water intrusion with high sensitivity and stability. It is something.

[Prior Art 1] Submersible pumps, marine engines, and the like used underwater are susceptible to water infiltration depending on the environment in which they are used. Therefore, in such equipment, a sill device is installed to prevent water from entering the oil chamber provided for insulating motor windings and lubricating sliding parts, deteriorating its characteristics and damaging the equipment. It is attached. However, even if a seal device is attached in this way, its sealing performance is not perfect;
It is not possible to eliminate the risk of water entering the oil chamber. For this reason, measures have been taken to ensure that if water gets into the oil chamber, maintenance must be performed before the equipment is damaged. Usually, a moisture detector is installed in the oil chamber.
The necessity of the above-mentioned maintenance is determined based on the detection of water by this moisture detector.

Conventionally, liquid level gauges have generally been used as moisture detectors. That is, when water enters the oil chamber, the oil level rises, and the level gauge detects this to determine whether or not water has entered.

[Invention or Problem to be Solved] However, when water intrusion is detected by a liquid level gauge as described above, due to the dead zone of the liquid level gauge, a considerable amount of water has already entered by the time it is detected. This often caused major problems such as equipment damage.

Therefore, it is possible to use a dielectric constant moisture meter as a moisture detector that can detect water intrusion with high sensitivity. This detects changes in dielectric constant due to water intrusion. However, although this dielectric constant moisture meter can be expected to detect with extremely high sensitivity, changes in the dielectric constant are greatly affected by various conditions such as temperature, so it is difficult to detect moisture under various temperature conditions such as submersible pumps and marine engines. It is virtually impossible to stably detect water intrusion with the equipment used in this field.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a moisture detector that can detect water intrusion into an oil chamber with high sensitivity and stability.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a water-permeable container that is provided in an oil chamber to block oil and allow only water that has entered the oil chamber to pass therethrough; The device includes a water-absorbing and expanding material filled inside an aqueous container, a gauge plate that deforms due to the expansion of the water-absorbing and expanding material, and a strain gauge that detects deformation of the gauge plate.

[Function] When the water that has entered the oil chamber passes through the water-permeable container and is absorbed by the water-absorbing and expanding material, the water-absorbing and expanding material expands due to its water absorption action, and this expansion deforms the gauge plate. Detected by strain gauge. Therefore, according to the present invention, water intrusion can be detected with high sensitivity and stability.

[Example 1 An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 shows a submersible pump to which a moisture detector according to an actual journey is applied. In this submersible pump 1, outside 1! With Gesink 4 consisting of i2 and inner cylinder 3,
A flow path 5 for water to be pumped is divided into sections. An electric motor R6 is fixed inside the inner cylinder 3, and an impeller 7 is connected to the output shaft of the electric motor 6. The impeller 7 passes through the inner cylinder 3 so as to be located on the upstream side of the flow path 5. It is directly connected to the output shaft via the rotating shaft 8. A sill device 10 is attached to a penetrating portion 9 of the inner cylinder 3 through which the rotating shaft 8 passes, so that water pumped up in the flow path 5 does not enter the inner cylinder 3. Oil F is supplied into the inner cylinder 3, which is sealed by the seals W10, and an oil chamber 11 for completely insulating the 6 windings of the motor is defined.

By the way, if the sealing performance of the sealing device 10 deteriorates, water will enter the oil chamber 11 and the electric motor 6
This results in serious problems such as the insulation of the winding being reduced and damage occurring. Therefore, in the submersible pump I, a moisture detector 12 for detecting water intrusion is installed in the lower part of the oil chamber 11 in a state immersed in the oil F.

As shown in FIG. 1, the moisture detector 12 mainly consists of a detector body 131, a water-permeable container 14. Water absorption expansion material 15° gauge plate 16
and a strain gauge 17.

As shown in the figure, the detector main body 13 is formed into a substantially stepped cylindrical shape, and has a male threaded portion 18 screwed into the inner cylinder 3 at one end, and a female threaded portion 19 at the other end. ing. A water-permeable container 14 for allowing only water that has entered the oil chamber 11 to pass therethrough is screwed and attached to the female threaded portion 19 . The water-permeable container 14 contains oil F
It is formed into a substantially bottomed cylindrical shape using a well-known material that blocks water and allows only water to pass through, and a male threaded portion 20 formed on the outer peripheral surface on the opening side is screwed into one of the female threaded portions. The interior of the water-permeable container 14 is divided into two chambers by a gauge plate 16, one of which is filled with a water-absorbing and expanding material 15. Here, the water-absorbing and expanding material 15 is made of a so-called super-water-absorbing polymer material that has a large water-absorbing capacity and water-holding capacity so that a pressure difference is generated between the two chambers with extremely high sensitivity due to its water-absorbing action. For this reason, the swelling caused by water absorption is significantly large. On the other hand, the gauge plate 16 is formed into a thin plate shape so as to easily convert the pressure difference between the two chambers into its deformation, and has one end side facing the detector main body 1.
8 and supported in a cantilevered manner. A strain gauge 17 for detecting the amount of deformation of the gauge plate 16 is attached to the surface of the gauge plate 16. The strain gauge 17 is connected to a detection circuit (not shown) via a cable 21 that passes outside the inner cylinder 3 and is led out of the outer cylinder 4.

Next, the operation of the submersible pump 1 to which the moisture detector 12 is applied will be explained.

Now, when the electric motor 6 is driven to rotate the impeller 7 via the rotating shaft 8, water will be pumped up along the arrow direction shown in FIG. If there is, water will enter the oil chamber 11.

Here, since the water has a higher specific gravity than the oil F, it enters the lower part of the oil chamber 11. Since a moisture detector 12 is installed in the lower part of the oil chamber 11, water that has entered the oil chamber 11 passes through the water-permeable container 14 and enters the inside thereof, and is absorbed by the water-absorbing and expanding material 15. This causes the water-absorbing and expanding material 15 to expand, creating a pressure difference between the two chambers in the water-permeable container 14 divided by the gauge plate 16. Due to this pressure difference, a force that tries to deform the gauge plate 16 acts on the gauge plate 16, and the gauge plate 16 is elastically deformed so that its restoring force and the water separation limit force of the water-absorbing and expanding material 15 are balanced.

Alternatively, the force that attempts to deform the gauge plate 16 overcomes the restoring force, causing the gauge plate 16 to be plastically deformed.

Along with the deformation of these gauge plates 16, the strain gauge 17
is also deformed, and the strain gauge 17 detects the intrusion of water into the oil chamber 11.

In this way, when water intrusion is detected, the submersible pump 1 will be subjected to maintenance.

That is, after the submersible pump 1 is disassembled and inspected and any malfunctioning parts are repaired, the moisture detector 12 and the oil F are replaced with new ones, and then the submersible pump 1 is assembled.

Therefore, according to this embodiment, the two in the water-permeable container 14 are
The expansion of the water-absorbing and expanding material 15 filled in one of the chambers creates a pressure difference between the two chambers, deforming the gauge plate 16, and detecting the deformation with the strain gauge 17. Intrusion of water into the interior of the device 11 can be detected with high sensitivity and stability. In particular, even if the gauge plate 16 is slightly elastically deformed due to temperature expansion of the water-absorbing and expanding material 15, the deformation of the gauge plate 16 due to the expansion of the water-absorbing and expanding material 15 is much greater, so the water detectability is reduced. It is not something that will be done.

As a result, the submersible pump 1 can be subjected to maintenance before the insulation of the electric FI 6 deteriorates and a major problem arises in which the cap is damaged.

Further, intrusion of water can be detected with a simple structure like the above-mentioned bucket structure, and an inexpensive moisture detector can be obtained. As a result, the moisture detector 12 becomes unusable due to water intrusion.
The economic burden is extremely small.

Another embodiment of the invention is shown in FIG.

The moisture detector 22 according to the second embodiment has a gauge plate 26
Intrusion of water into the oil chamber 11 is detected by applying an attractive force to the oil chamber 11 and detecting its elongation.

That is, a ring member 33 is concentrically and integrally attached to the negative side surface of the water-permeable plate 24 formed in a substantially disk shape via a substantially cylindrical bellows 32.
are screwed into two female threaded portions of the detector main body 23. The space inside the moisture detector 22 surrounded by the bellows 32 and the water-permeable plate 24 is filled with a water-absorbing and expanding material 25, and the gauge plate 26 is filled along the expansion and contraction direction of the bellows 32.
or has been constructed. The gauge plate 26 is formed into a thin plate shape, and has one end fixed to the detector main body 23 and the other end fixed to the water permeable plate 24. A pair of strain gauges 27 for detecting the amount of elongation of the gauge plate 26 are provided at substantially medium positions on the opposing surfaces of the gauge plate 26.
27 is attached.

In this second embodiment, water that has entered the oil chamber 11 passes through the water-permeable plate 24 and enters the inner space of the moisture detector 22, and is absorbed by the water-absorbing and expanding material 25.
5 and increases the pressure in the space. This pressure increase causes the bellows 32 to expand in its axial direction, and a tensile force acts on the gauge 0 plate 26, causing it to elongate.

This elongation is measured by the strain gauge 27 as in the above embodiment.
27, and the intrusion of water into the oil chamber 11 is detected.

Therefore, in this second embodiment, the # product of the filled water-absorbing and expanding material 25 can be increased, and a more compact and highly sensitive moisture detector 22 can be obtained.

[Effects of the Invention] In summary, the present invention exhibits the following excellent effects.

(1) The gauge plate is deformed by the expansion of the water-absorbing expansion material, and the deformation is detected by a strain gauge, making it possible to detect water that has entered the oil chamber with high sensitivity and stability, resulting in more reliable moisture detection. You can get the equipment.

(2) As a result, it is possible to reliably perform maintenance on applied equipment such as submersible pumps and marine engines before they are damaged by water intrusion, and the reliability of these equipment can also be improved.

1

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention, Fig. 2 is a schematic configuration diagram of a submersible pump to which the embodiment is applied, and Fig. 3 is a sectional view showing other 11 examples of the present invention. be. In the figure, 11 is an oil chamber, 12 is a moisture detector, 14 is a water-permeable container, 15 is a water-absorbing and expanding material, 16 is a gauge plate, and 17 is a strain gauge.

Claims (1)

[Claims] 1. A water-permeable container provided in an oil chamber that blocks oil and allows only water that has entered the oil chamber to pass through; a water-absorbing and expanding material filled inside the water-permeable container; A moisture detector comprising a gauge plate that deforms due to expansion and a strain gauge that detects the deformation of the gauge plate.