RU2739215C1 - Medium change sensor - Google Patents

Abstract

FIELD: electrical equipment.SUBSTANCE: invention relates to electrical engineering, in particular to a medium change sensor, and can be used in automation systems of objects submerged and extracted from an aqueous medium. Sensor comprises a casing with a sealed housing, which contains body parts, in which elastic membranes are fixed on the brackets opposite each other to form inner volumes. Cantilever U-shaped resilient contacts are fixed on membranes in their centres on external surfaces. On the end of the casing there are covers, between which a sealed resilient partition is fixed, which separates the inner volume of the casing from the external medium. Surfaces of cover plates adjacent to elastic partition wall are made with depth increasing gradually from the point of fixation to the centre of elastic partition. In covers there are channels for pressure transfer. Volumes on both sides of elastic partition wall exceed temperature variations of volume of dielectric liquid having running temperature range exceeding operating temperature range. Dielectric fluid completely fills internal volume of casing and membranes.EFFECT: technical result of the invention is low error of operation and increased reliability of operation in water medium, including sea water.1 cl, 6 dwg

Description

The invention relates to the field of instrumentation, in particular, for use in automation systems for objects submerged and removed from the aquatic environment.

Currently, various designs of hydrostatic switches and pressure sensors are known, which can be used as sensors for changing the medium, however, the former, due to the impossibility of tuning to small settings, do not allow tracking the actual boundary of the medium change with acceptable accuracy, the latter are operable only in neutral (non-conductive and non-corrosive) liquids, that is, they do not fulfill the task.

Known hydrostatic switch, which can be used as a sensor for changing the environment (immersion from air in water, as well as extraction from the aqueous medium into the air), containing a housing with a fixed elastic membrane, interacting through a rod with a contact system [RF patent No. 2691158, IPC G01L 19/12, H01H 35/24 publ. 06/11/2019, bul. No. 17]. The hydrostatic switch is operational when immersed in seawater and corrosive liquids, however, the minimum threshold response pressure provided by the elastic membrane corresponds to a significant immersion depth, which is unacceptable for a sensor of changes in the external environment, which is required to operate when passing the actual boundary of the medium change. The field of application of the known hydrostatic switch as a medium change sensor is very limited.

Known threshold pressure sensor of the executive switching device [RF patent No. 2617708, IPC N01H 35/14, publ. 04/26/2017], which can be used as a sensor for changing the environment, containing a casing with a sealed housing located in it, in which, with the formation of internal volumes, elastic membranes are fixed on brackets counter to each other with contacts in the center on the external surfaces.

The known threshold pressure sensor can be adjusted to the set pressure corresponding to the hydrostatic pressure of water at shallow depths, that is, near the interface between air and water media, however, the known sensor is not operable in electrically conductive liquids, for example, in seawater, in which it will inevitably be electrically connected with housing parts, all electrical circuits of the sensor, that is, the sensor will be completely inoperative. The reliability of the sensor will not be ensured, and the scope of the sensor is limited only to distilled water without any impurities.

This pressure sensor is a medium change sensor is considered as a prototype.

The objective of the claimed invention is to create a reliable sensor for changing the environment and expand the scope.

The technical result, to which the claimed invention is directed, is to provide a small response error and reliable operation in an aquatic environment, including sea water, with a wide temperature range.

The specified technical result is achieved by the fact that in the sensor for changing the environment containing a casing with a sealed housing located in it, in which, with the formation of internal volumes, membranes with elastic contacts in the center on the outer surfaces are fixed counter to each other, according to the invention, it is provided with fixed at the end of the casing with covers, between which a sealed elastic partition is located, the inner volume of the membranes and the casing is completely filled with a dielectric liquid with an operating temperature range exceeding the operating temperature range of the sensor, and is separated from the external environment by a sealed elastic septum, and the surfaces of the covers facing the sealed elastic septum are made with depth smoothly increasing from the point of attachment to the center of the elastic partition and have channels for transmitting pressure, while the volumes formed by the adjoining surfaces of the covers and the elastic partition exceed the temperature changes in the volume of the dielectric liquid within the operating temperature range of the sensor.

Also, in the medium change sensor, in order to increase the reliability of operation, the volume of the sealed housing with placed elastic contacts is filled with dried gas with a dew point below the lower operating temperature range of the sensor.

Equipping the medium change sensor with covers fixed on the end of the casing, with the placement of a sealed elastic partition between them and filling the inner volume of the membranes and the casing with a dielectric liquid with a range of operating temperatures exceeding the operating temperature range of the sensor, eliminates direct contact of membranes with an external aqueous, often electrically conductive medium. ensuring the possibility of transferring external pressure to them without significantly reducing it and maintaining the performance of the sensor after being at low and high ambient temperatures in the operating temperature range.

The dielectric liquid, due to its non-electrical conductivity, excludes the electrical circuit between the membranes until the elastic contacts are closed.

The design of the body surfaces facing the elastic septum, with a smoothly increasing depth from the point of attachment to the center of the elastic membrane and channels for pressure transmission, excludes damage to the elastic membrane under pressure, ensuring trouble-free operation of the sensor and a long service life.

The implementation of the volumes formed by the adjacent surfaces of the body parts and the elastic septum, exceeding the temperature changes in the volume of the dielectric liquid at the limiting operating temperatures, excludes the destruction of the elastic septum, as well as the change in the characteristics of elastic membranes from the temperature change in the volume of the dielectric fluid.

Filling the volume of the sealed housing with placed elastic contacts with dried gas with a dew point below the lower operating temperature range of the sensor excludes the loss of dew and water condensate in the volume with placed elastic contacts and the failure of the sensor as a result.

The inventive sensor for changing the environment is operational when immersed and removed from various aqueous media, including sea (electrically conductive) water, and provides:

- high reliability (preservation of the response setting under the action of large overload hydrostatic pressures);

- small response error, that is, response as close as possible to the interface;

- stable electrical parameters of the contact during long-term operation;

- tightness;

- small weight and size characteristics.

In the claimed technical solution with respect to the prototype, such basic technical characteristics as operation error and reliability are improved, in addition, the scope of application is expanded by ensuring operation in various aqueous environments, both in fresh and in sea water. Small error ensures the required response of the proposed sensor practically at the interface (water and air) environments. This characteristic is the main technical characteristic of the developed sensor for changing the environment. Maintaining the set point under the action of significant hydrostatic pressure ensures reliable operation of the sensor for long periods of operation without significant restrictions on operating conditions in terms of the maximum immersion depth.

Thus, the combination of all the above features creates the conditions for ensuring a small operating error, increasing the reliability of the sensor and expanding the scope of application.

The presence in the claimed invention of features that distinguish it from the prototype makes it possible to consider it as corresponding to the "novelty" condition.

New features, which contain the distinctive part of the claims, are not identified in technical solutions for a similar purpose. On this basis, we can conclude that the claimed invention meets the condition "inventive step".

The invention is illustrated by drawings:

in fig. 1 shows an axial section of a sensor for changing an aqueous medium to an air one;

in fig. 2 - the design of elastic contacts fixed on the membranes in the initial state (liquid not shown);

in fig. 3 - the design of elastic contacts fixed to the membranes in a closed state (liquid not shown);

in fig. 4 - compensation for the increase in the volume of the dielectric fluid at the highest operating temperature;

in fig. 5 - compensation for the decrease in the volume of the dielectric fluid at the lowest operating temperature;

in fig. 6 is an axial section of a design variant of the sensor for changing the air medium to the water one.

The sensor for changing the environment (Fig. 1-6) contains a casing 1 with a sealed casing located in it, containing body parts 2, 3. In the body parts 2, 3 with the formation of internal volumes, elastic membranes 5 are fixed on brackets 4 opposite to each other. the membranes 5 in their centers on the outer surfaces are fixed cantilever U-shaped elastic contacts 6, for example, welded, pressed by the free ends to the stops 7 also fixed on the membranes 5 (Fig. 1). The stroke of the centers of the membranes 5 against the stop in the brackets 4 at overload pressure does not exceed the permissible elastic deflection of the free end of each elastic contact 6. The membranes 5, pressed against the brackets 4, exclude further deflection of the elastic contacts 6, as a result of which, after the action of the overload pressure, the elastic contacts 6 do not have permanent deformations (retain their shape and spatial arrangement of points of contact).

Elastic contacts 6, fixed on the membranes 5, are mutually rotated by about 90 ° to ensure stable point contact and avoid changes in relative position. Membranes 5 with an increase in hydrostatic pressure bend towards each other (approach).

Brackets 4 are installed on bushings 8, insulated with glass solder 9 from body parts 2, 3. Channels 10 made in body part 3 provide supply of controlled pressures to the inner cavities of membranes 5. An additional channel 10 (not indicated by the position in the drawing) is used to accommodate the connecting wires.

At the end of the casing 1, covers 11 and 12 are fixed. Between the covers 11 and 12, an elastic sealed elastic partition 13 is fixed, separating the inner volume of the casing 1 from the external environment. The baffle 13 is made of an elastic material, such as rubber, in order to avoid a significant decrease in the pressure transmitted to the membranes 5. The surfaces 14 of the covers 11, 12 adjacent to the elastic partition 13 are made with a depth that gradually increases from the attachment point to the center of the elastic partition 13. In the covers 11, 12 channels 15 are made for transmitting pressure. The volumes 16 on both sides of the elastic septum 13 exceed the temperature changes in the volume of the dielectric liquid 17 having an operating temperature range that exceeds the operating temperature range of the sensor. The dielectric liquid 17 completely fills the internal volume of the casing 1 and membranes 5. The location of the elastic baffle 13 at the maximum positive temperature is shown in FIG. 4, at a minimum negative temperature - in Fig. 5. In this case, the volume 18 of the sealed housing, with placed elastic contacts 6, is filled with dried gas with a dew point below the lower operating temperature range of the sensor.

Filling the volume 18 with the placed elastic contacts 6 with dried gas with a dew point below the lower operating temperature range of the sensor excludes the loss of dew and water condensate in the volume with the placed elastic contacts and the failure of the sensor as a result.

The use of liquid 17 with an operating temperature range of operation exceeding the operating temperature range of the sensor excludes the sensor failure after being at low and high ambient temperatures in the operating temperature range.

Dielectric fluid 17 (due to its non-electrical conductivity) excludes the electrical circuit between the membranes 5 until the elastic contacts 6 are closed.

The sensor of FIG. 1 ensures the closure of contacts 6 during the transition, for example, from an aqueous medium to an air one. The sensor of FIG. 6 ensures the closure of contacts 6 during the transition, for example, from air to water. The sensor contacts 6 according to the embodiment of FIG. 6 are made on membranes 5 in one piece. The differences in the sensor versions of FIG. 1 and FIG. 6 only in contact design 6.

The sensor is connected to the external electrical circuits of the object of application through current leads 19 mounted on the part 20 of the casing 1 on insulators 21. The shtengel 22 is designed to fill the inner volume of the sensor casing during its manufacture with a dielectric liquid 17. The shtengel 22 is crimped and sealed during the sensor manufacturing process.

Wires 23 and 24 provide the electrical connection of the brackets 4 with the corresponding current leads 19.

Current leads 19 with installed wires 23, 24 are sealed from the ends by welding.

The medium change sensor works as follows.

In air, the sensor contacts 6 for the embodiment of FIG. 1 are closed (Fig. 3), in an aqueous medium - open (Fig. 2). When passing from an aqueous medium to an air medium, the hydrostatic pressure stops acting on the elastic partition 13, and therefore on the membranes 5, which take their original shape, closing the contacts 6.

During the subsequent transition from air to water, the elastic partition 13 is affected by hydrostatic pressure, which is transmitted practically unchanged through the dielectric fluid 17 to the membranes 5, which, elastically deforming, open the contacts 6. In this case, the elastic characteristics of the membranes 5 can ensure that the contacts 6 are closed on insignificant depth (practically at the interface between the media).

With an increase or decrease in the volume of the dielectric liquid 17 due to a change in the ambient temperature, the elastic partition 13 bends, compensating for the volume changes. The volumes 16 on each side of the elastic septum 13 are sufficient for this compensation.

The smoothly varying depth of the surfaces 14 adjacent to the elastic partition 13 and the execution of channels 15 with a small diameter in the covers 11, 12 excludes the destruction of the elastic partition 13 under the action of significant hydrostatic pressures. Surfaces 14 can be, for example, spherical.

In air, the sensor contacts 6 for the embodiment of FIG. 6 are open, and closed in the aquatic environment.

The sensors are efficient in various water environments, including seawater. Seawater, which is a conductor, in the inventive sensor does not directly interact with membranes 5, brackets 4 and bushings 8 (which are elements of an electric circuit when contacts 6 are closed and opened) due to the organization of an intermediate volume of the sensor filled with a dielectric liquid 17.

Thus, the claimed technical solution will make it possible to create a sensor for changing the medium with a low response error and increased reliability. The inventive medium change sensor can be implemented with a mass of 60 g and a volume of not more than 20 cm ³ .

The information provided indicates the fulfillment of the following set of conditions when using the claimed invention:

- the inventive medium change sensor is intended for use in automation systems for objects immersed in an aqueous medium;

- the inventive sensor, when used, is capable of providing reliable operation when the external environment changes;

- for the inventive sensor in the form in which it is described in the claims, the possibility of its implementation is confirmed using the means and methods described in the application and known before the priority date.

Therefore, the declared sensor of the change of medium meets the condition of "industrial applicability".

Claims (2)

1. A medium change sensor containing a casing with a sealed casing located in it, in which, with the formation of internal volumes, membranes with elastic contacts in the center on the outer surfaces are fixed opposite to each other, characterized in that it is equipped with covers fixed at the end of the casing, between which a sealed elastic baffle is located, the inner volume of the membranes and the casing is completely filled with a dielectric liquid with a range of operating temperatures exceeding the operating temperature range of the sensor, and is separated from the external environment by a sealed elastic baffle, and the surfaces of the covers facing the sealed elastic baffle are made with a smoothly increasing from place fixing to the center of the elastic septum with a depth and have channels for pressure transmission, while the volumes formed by the adjacent surfaces of the covers and the elastic septum exceed the temperature changes in the volume of the dielectric liquid in the temperature range of the sensor operation. 2. The medium change sensor according to claim 1, characterized in that the volume of the sealed housing with placed elastic contacts is filled with dried gas with a dew point below the lower operating temperature range of the sensor.

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