RU2545177C2 - Device for pressure difference sensorial determination in work pipeline - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: device is intended to determine pressure difference in the work pipeline. The device contains choke installed in the work pipeline and connected in parallel with it pressure difference valve, made in form of a cylindrical body with piston, at its both sides two spring elements are installed for its positioning in middle position as initial position without pressure difference.

EFFECT: improved device reliability.

9 cl, 2 dwg

Description

FIELD OF THE INVENTION

The invention relates to a device for sensory determination by sensors arising between the first place and located in the direction of flow at a distance from the second place of the pressure difference in the area introduced into the working pipeline through which the compressed air passes the throttle.

State of the art

The scope of the invention proposed for consideration covers the use of technical fluids, in which the presence of a pressure-transmitting medium in the pipeline must be determined, as well as its direction for converting this information into a signal for a higher-level control device. Possible applications are, for example, air pressure monitoring devices, in which the supply of pressure to at least one pneumatically sprung vehicle tire is controlled. At the same time, the higher-level control device requires technically determined by means of sensors information about the actual pressure of the connected pneumatically sprung tires. However, other applications are possible, for example in pneumatic door control devices or in the field of technology of internal combustion engines.

From EP 0003188 A1, a technical solution is found for determining the pressure difference in the zone of the throttle introduced into the working pipeline through which the pressure transmitting medium passes. In this case, the working pipeline conducts combustion air, the supply of which must be regulated. The presence of air flow through the working pipeline is determined by its selection in two places located at a distance from each other. In the area of constriction causing throttling, as well as in the direction of flow, before this constriction, the pressure prevailing there from both sides is supplied to an elastomer membrane placed in a closed housing. In this case, the lower stop position can be adjusted by means of a set screw. By means of a lever mechanism, the position of the elastomer membrane is detected depending on the pressure difference between the two places. Based on the actual position of the elastomer membrane, it can thus be concluded that the pressure difference prevails in the throttle zone.

DE 2318973 A1 identifies another device for technical determination by means of pressure difference sensors, in which this pressure difference is supplied to both sides of the piston in accordance with the magnitude and sign in order to obtain switching signals for the superior control device. The piston with the possibility of axial movement is located in the housing, which on both sides of the piston spring is mounted with the possibility of longitudinal movement against the spring force of the piston and forms one connection device for supplying the pressure transmitting liquid to the pressure chamber. Two spring devices are attached to the piston in order to displace it in two directions, which with their first ends facing each other constantly rest on the stops on the housing, and with their second ends - on the thrust washers mounted on the structural element. The end surfaces facing away from the thrust washers of the respective springs, depending on the support on the piston and on the housing, are conjugated in such a way that both thrust washers rest on the corresponding supports on the piston and the housing, which is different from the end positions of the piston, while when the piston is displaced in the direction of the corresponding displacement, the thrust washer rests only on the corresponding support on the piston, and, on the contrary, the back washer in the direction of the corresponding displacement, the thrust washer rests only on the corresponding support on the housing. The piston is equipped with means for controlling its position by means of electrical switching means. As electrical means of switching, two jog switches located opposite each other are provided, the variable actuation of which is carried out by means of a gripper, which is mechanically connected to the piston of the differential pressure sensor.

The disadvantage of this prior art is a really large number of structural elements, due to the presence of thrust washers, pressure springs, seals, etc.

From DE 4226941 A1 there follows another technical solution for a differential pressure switch, in which the previously described problem is solved by the fact that some functionally integrated structural elements are combined with a contactless operating switch. A tape clamped on one side is located in a rectangular case, and the position of the free end of this tape depends on the pressure difference. Compared pressure sources are included in the opposite tape parallel to the housing wall. Using a proximity sensor, the movement or position of the free end of the tape is converted to the corresponding electrical signals. If the tape is made in the form of a metal strip, then the sensor can be made as an inductive sensor. It is further proposed to magnetize at least the movable portion of the tape to ensure reliable measurement.

Disclosure of invention

And with the help of this technical solution, it is possible to measure the pressure difference and convert it into a switching signal. This differential pressure switch is used in the preferred embodiment for adjusting the running gear, in which the pressure in the shock absorbers due to the transition changes from periodically traction to periodically push. The disadvantage is, however, really sensitive design, which limits the scope of application of this technical solution.

The objective of the invention is to provide a device for technical determination by means of pressure difference sensors, which, when using simple structural elements, is made with a large margin of safety and always provides reliable measured values.

The problem is solved in combination with the distinguishing features of claim 1 of the claims. The following dependent claims demonstrate preferred embodiments of the invention.

According to the invention, the pressure is diverted in the first place in the flow direction in front of the throttle and in the second place in the flow direction not near, but after the throttle, for supplying the pressure difference through the throttle integrated into the working pipeline on both sides to the differential pressure valve connected in parallel for this . The differential pressure valve, in cooperation with the electrical switching device, transmits a double air supply or exhaust signal to the higher-order control device, if the differential pressure valve determines a significant positive or negative pressure difference through the throttle valve, which, in the framework of the device in accordance with the invention, serves in this regard as a specific type of measuring choke.

An advantage of the solution in accordance with the invention is, in particular, that the special arrangement of the measuring choke next to the differential pressure valve can be easily converted into an electrical switching device with a small number of structural elements. In this case, by means of the first pair connection of the measuring throttle and the pressure difference valve, the existing pressure difference is converted to a certain position. By pairing the differential pressure valve and the electrical switching device, the position thus obtained is used as a driving force for the electrical switching device. The electrical signal obtained in this way on the basis of the pressure difference can be used to initiate the start and end of applications based on the flow of compressed air in the working pipeline.

The differential pressure valve, which is used to convert the measured differential pressure into the installation movement, consists in the preferred embodiment of a cylindrical body with front-side connection elements for connecting to the first place and, accordingly, to the second place before / after the throttle and includes made with the possibility of axial two-way adjustment by means of a pressure differential valve piston, which is dynamically sealed relative to the body wall a. To position the valve piston in the middle position defined as the starting position without pressure difference, two spring elements are located on both sides of the valve piston, with their ends facing the valve piston adjacent to the end faces of the housing. Thus, two opposing piston valves are created and configured to be loaded against the spring force of the pressure chamber spring. Such a pressure differential valve is simple and reliable and consists of the previously mentioned small number of individual structural elements.

The interaction of this differential pressure valve with an associated electrical switching device is preferably carried out in accordance with the two preferred embodiments described below.

According to a first embodiment of the invention, the use of magnetic coupling means is proposed. As a magnetic means of connection, the permanent magnet integrated in the preferred embodiment of the valve piston interacts with the switching device made in the form of an inductive switch on the reed switches. In this case, the valve piston may also consist entirely of a permanent magnet. Such magnetic means of connection allow for the non-contact control of an electrical switching device, which allows hermetic placement of the structural elements of the differential pressure valve inside a fully enclosed housing. In this way, sealing problems are prevented and, thanks to the magnetic means of connection, a generally compact device can be realized.

In accordance with a second preferred embodiment of the invention, it is proposed that the differential pressure valve by means of a mechanical connection means interacts with an electrical switching device. In this case, a control rod connecting the valve piston to the switching device, which is perpendicular to the axis of movement of the valve piston in the direction of the electrical switching device, can be provided as a suitable mechanical coupling means. The control rod can be either a valve piston element or a switching device element. In this case, the electrical switching device can be formed in the form of a traditional multi-pole change-over switch, which is offered as a standard structural element.

In accordance with the improving control of the electrical switching device implemented as a rocker switch, it is proposed that the valve piston be located between two elastomer membranes that define one discharge chamber, which are connected to the first and, respectively, second position of the throttle. The distal end of the control rod interacts with the radial recess on the valve piston to control the switch. Due to both elastomer membranes including the valve piston, the transition zone interacting with the control rod and the electric switch is not under pressure, so no other tightness measures are required. The thickness of the membrane material from the elastomer is chosen such that in the case of equilibrium pressure, that is, in the absence of a pressure difference, a neutral middle position is established, without the need for additional spring elements.

In a preferred embodiment, the electrical switching device within the framework of the proposed invention has three switching positions and transmits to the superior preferably electrical switching device in the above-mentioned middle position of the valve piston a signal that there is no need to apply pressure.

If, on the contrary, the piston of the valve assumes one of the final thrust positions on the left or on the right side, then, in this way, a signal can be given indicating the need for air supply or exhaust. Thus, the valve function 3 / n can be converted. Valve function 2/2 can be realized on the basis of the sum of the available capabilities by the fact that the signals are given only in the case of a neutral position as the end position and if air supply or exhaust is necessary.

According to a preferred case of application to the equipped device according to the invention for the technical determination by means of pressure difference sensors, the working pipeline is supplied with compressed air from the inlet side from the electro-pneumatic valve in order to fill the closed tank from the outlet side in the preferred embodiment. The device in accordance with the invention then determines whether compressed air passes into the tank and when the flow equalization is established, and transmits the corresponding electrical signal to a higher-level control device, which, in turn, drives the control valve. The electronic control device can obtain the desired pressure level manually or automatically. Such an example of use can be applied when filling pneumatically sprung tires of a vehicle, filling tanks-shaped storage tanks for compressed air, etc.

Brief Description of the Drawings

Other measures that improve the invention are shown in more detail below in combination with a description of two preferred embodiments of the invention based on the drawings, in which:

figure 1 is a schematic illustration of a device for determining the pressure difference in the first embodiment, and

figure 2 - device for determining the pressure difference in the second embodiment.

The implementation of the invention

In accordance with FIG. 1, a stream of compressed air, leaving only the electropneumatic control valve 1 shown here schematically, passes through the working line 2 into a closed tank 3 also shown schematically, which must be filled with compressed air. A restrictor 4 is used to restrict the active cross-section of the flow, which narrows the active cross-section of the flow. In the first place 5a in front of the throttle 4 and in the second place 5b after the throttle 4, different values of pressure are observed when compressed air passes through the working line 2. A pressure difference valve 6 connected in parallel with the throttle 4 determines the pressure difference resulting from various pressure values in the first place 5 a and in the second place 5 b, in which the above-mentioned pressure values in the working line 2 are highlighted.

The pressure difference valve 6 consists mainly of a cylindrical body 7 with elements for connecting to the pipeline on each end side for connecting to the first place 5a and second place 5b of the working pipe 2. A piston 8, made with the possibility of axial two-sided adjustment, is placed centrally inside the body 7 valve. The valve piston 8, as a result of loading with two spring elements 9a and 9b oppositely acting on it, is in the initial position characterized by the absence of a pressure difference in the central position shown in the drawing.

The pressure difference valve 6 in such an embodiment of the invention interacts with magnetic switching means with an electrical switching device 10 located near it. As a magnetic means of connection, the valve piston 8 in this case consists of a permanent magnet, while the electric switching device 10 interacting with it is made in the form of an inductive switch on the reed switches. If the valve 6 of the pressure difference, depending on the direction of flow through the working pipe 2, determines a significant positive or negative pressure difference through the throttle 4, then such an event technically established by means of the sensor by means of an electrical switching device 10 can be reported to the upstream control device 11, which depending from the specified control values and the set value of the pressure difference sets the electro-pneumatic control valve 1.

If, after opening the electro-pneumatic control valve 1, the compressed air passes into the connected tank 3 until the latter is completely filled, then it is finally impossible to determine any pressure difference through the throttle 4, so that the electronic control device 11 can then move the electro-pneumatic valve 1 from open to closed position.

In accordance with the second embodiment of FIG. 2, the valve piston 8 ′ is located between two elastomer membranes 12a and 12b that define one discharge chamber 13a and 13b, respectively, which are connected to the first and second, not shown places of the working pipeline similarly to the previously described embodiment of the invention.

To actuate an electrical switching device 10 'coupled to the valve piston 8', a mechanical coupling means is used which in the form of a control rod 14 engages with a corresponding radial recess 15 on the valve piston 8 '. The axial movement of the valve piston 8 ′ obtained due to the pressure difference thus leads to switching with the tilt of the control rod 14 of the control of the electrical switching device 10 ′ for the purpose already indicated in connection with the foregoing description.

The invention is not limited to the two preferred embodiments described above. Moreover, other embodiments are possible, which are included in the protective scope of the following claims. So, for example, it is also possible to use the device in accordance with the invention for technical determination by means of pressure difference sensors for a different purpose than the purpose of supplying pressure to a closed tank. Particularly preferred is its use with a tire pressure monitoring device for pneumatically sprung vehicle tires.

List of Reference Items

1 - electro-pneumatic valve

2 - working pipeline

3 - tank

4 - throttle

5th place

6 - differential pressure valve

7 - case

8 - valve piston

9 - spring element

10 - electrical switching device

11 - control device

12 - elastomer membrane

13 - discharge chamber

14 - control rod

15 - deepening

Claims (9)

1. A device for sensory determination of the pressure difference arising between the first place (5a) and the second position (5b) located in the direction of flow at a distance from it of the second place (5b) in the zone introduced into the throttle (4), moreover, pressure is diverted in the first place (5a) the flow direction in front of the throttle (4) and in the second place (5b) in the direction of the flow after the throttle (4), for applying a pressure difference through the throttle (4) from both sides to the difference valve (6, 6 ') connected in parallel for this pressure, which in interacting with the electric device (10, 10 '), the switching is made with the possibility of transmitting to a higher device (11) the control signal, if the valve (6, 6') the pressure difference determines a significant positive or negative pressure difference through the throttle (4), different the fact that the pressure difference valve (6, 6 ') for determining a positive or negative pressure difference in the working line (2) through which compressed air passes consists of a cylindrical body (7) with an element located on the front side by connecting to the pipeline for connecting to the first and second places (5a, 5b) of the working pipeline (2), which contains an axial two-way adjustment by means of a pressure difference of the valve piston (8), on both sides of which to position it in the middle position in As the initial position without pressure difference, two spring elements (9a, 9b) are located. 2. The device according to claim 1, characterized in that for the interaction of the electrical device (10, 10 ') switching with the valve (6, 6') of the pressure difference provides mechanical or magnetic means of connection. 3. The device according to claim 2, characterized in that, as a magnetic means of connection, the permanent magnet forming the valve piston (8) interacts with a switching device (10) made in the form of an inductive switch on the reed switches. 4. The device according to claim 2, characterized in that a connecting piston (8 ') of the valve with a switching device (10') of the control rod (14) is provided as a mechanical means of connection. 5. The device according to claim 4, characterized in that the piston (8 ') of the valve for switching with tipping of the rod (14) of the control of the device (10') of switching is located between two membranes (12a, 12b) of elastomer, which limit one chamber (13a, 13b) injection, which are connected to the first and, accordingly, the second place (5A, 5b) of the working pipeline (2). 6. The device according to claim 1, characterized in that the distal end of the stem (14) of the control of the electrical switching device (10 ') is engaged in a corresponding radial recess (15) on the valve piston (8'). 7. The device according to claim 1, characterized in that the electrical switching device (10, 10 ') has three switching positions and in the middle position corresponding to the middle position of the valve piston (8, 8') does not send a signal to the control device (11) the need for pressure supply, while in the end positions on both sides a signal is given indicating the need for air supply or exhaust. 8. The device according to claim 1, characterized in that the working pipeline (2) is configured to supply pressure at the outlet of the electro-pneumatic control valve (1) to at least one closed tank (3). 9. The device according to claim 8, characterized in that the closed reservoir (3) is formed by means of a pneumatically sprung vehicle tire or by means of a tank-shaped reservoir for collecting compressed air.

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