JPH04232473A - Apparatus for monitoring flowing of fluid medium in fluid space - Google Patents

Abstract

PURPOSE: To attain large piston stroke assurance at a low flow velocity by disposing a device which functions effectively so as to discharge an excessive amount of medium to an inlet chamber when a piston slides to the first switching position. CONSTITUTION: Oil, after a pump is connected and a magnet value is opened, is sucked through a stand pipe and pressed into respective pipelines. When oil pressure in the pipeline is sufficiently high, a valve 22 is opened, therefore, oil pressure in an inlet chamber 28 increases. As a result, a piston 32 is lifted so as to maintain its shape against gravity or the force of a spring 43. Leakage of oil from a compensation passage 46 is inhibited by designing the whole cross- sectional surface of the passage 46 so as to be smaller than that laded by oil in the piston 32. This is the same as for a ring gap generated between a guide part 32a and a guide 31.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention is a device for monitoring the flow of a fluid medium in a fluid space having an inlet chamber and an outlet chamber, the device comprising: a casing surrounding the fluid space; a guide disposed, a piston slidably supported by the guide within the flow space, and a vent disposed within the flow space and configured to control flow of medium from the inlet chamber to the outlet chamber. A flow opening is provided, in which case the flow opening is closed after the piston has been moved into the first switching position, whereas the positive action of the medium on the piston causes the piston to The flow opening is at least partially opened after the piston has been moved into the second switching position, and a sensor is provided in cooperation with the piston for detecting at least one of the two switching positions. Regarding the format provided.

0002

BACKGROUND OF THE INVENTION In knitting machines, for example, devices of this type are used together with oil lubrication systems which can be controlled to supply lubricating oil to selected assemblies, tools, etc. A plurality of individual or grouped supply lines and injection nozzles or similar elements connected to the supply lines are provided. In this case, in order to be able to preselect the metering value of the lubricating oil supplied, the lubricating oil is usually supplied not continuously but intermittently, or often alternately one after the other, in each case in different supply lines. sent to the street. Therefore, in order to reliably control its functions,
Monitoring devices installed in or in front of the supply line indicate the orderly flow or cessation of oil in the supply line, and at the same time clearly identify the differences that should be assigned to these two conditions. It must be possible to generate two types of, for example electrical, switching signals.

Federal Republic of Germany Patent Application No. 3624
In a device of this kind disclosed in the specification of No. 982, a ring gap is formed between a bush-like guide and a piston guided within this guide, the width of which can be selected in advance. There is. The guide has a cross-sectional constriction forming a flow opening at the end facing the inlet chamber, against which the piston can rest against the edge of the constriction by gravity or by the force of a spring. It is. In the absence of lubricating oil flowing in the supply line, the axial flow opening therefore also functions as a stop, by means of which the piston is clearly positioned in the first switching position. . If, on the other hand, oil were introduced clearly in the direction of the supply line, the piston would be moved away from the flow opening, so that the oil could pass through the ring gap and flow along the piston into the outlet chamber. become.

Immediately after it leaves the edge of the flow opening, the piston can still be slid in a frictionally connected manner, that is to say by means of fluid friction forces, in the direction towards the second switching position, so that the piston has a relatively high The desired high functionality cannot be guaranteed unless oil pressure values and flow rates and thus relatively high oil flows are achieved. This means that at low oil flow rates, depending on the influence of the oil tube used, oil type, oil temperature, and other operating conditions, it is common to generate two distinct switching signals. Although the minimum piston stroke is set, for example, at 3 to 4 mm, taking into account that Hall detectors or similar devices must be used, the actual intended piston stroke is often less than this minimum. It is inevitable that a switching error will occur due to the fact that the value may be lower than the actual value. As a result, it is not possible to indicate the actual oil conveyance or the oil flow interruption that has occurred after the conveyance, or a false indication occurs.

Federal Republic of Germany Patent Application No. 3641
No. 737 discloses a device based on the same principle as in the type of device mentioned at the outset, but in which the piston is constructed as a sphere and its instantaneous operating position is Scanned by optoelectronic means.

Furthermore, Federal Republic of Germany Patent No. 284997
In the device disclosed in No. 4 (in particular FIGS. 2 and 4), also of the type mentioned at the outset, the flow openings are not provided axially but in the side wall of the hollow piston. the first in the hollow piston;
The switching position is covered by the guide. In this case, oil flow is only possible when the piston is forced to move away from its first switching position in a positive manner, that is, due to the pressure of the medium, until it at least partially opens the flow opening. After that. However, the piston stroke that can be achieved by a form-locking piston movement of this kind is not sufficient to generate two distinguishable signals, so that the piston does not move sufficiently after opening the flow opening. Until large piston strokes are obtained, additional frictional sliding has to be performed, as in other known monitoring devices, and therefore also in this known monitoring device, a considerable amount of pressure is required to allow the flowable medium to flow through. Large pressures and high flow rates are required.

[0007]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to improve the monitoring device of the type mentioned at the beginning and to improve the monitoring device when the flow pressure of the fluid medium is low and the flow velocity thereof is low. Another point is to ensure a sufficiently large piston stroke.

[0008]

[Means for Solving the Problems] According to the measures of the present invention proposed to solve the above-mentioned problems, it is possible to effectively discharge excess medium when the piston slides into the first switching position. The equipment to be used is assigned to the inlet room.

That is, the device for monitoring the flow of a fluid medium in a flow space of the present invention is a device for monitoring the flow of a fluid medium in a flow space having an inlet chamber and an outlet chamber. a casing surrounding the flow space, a guide disposed within the flow space, a piston slidably supported by the guide within the flow space, and a piston disposed within the flow space from the inlet chamber to the outlet chamber. a flow opening configured to control the flow of the medium, the flow opening being closed after the piston has slid into the first switching position; On the other hand, the flow opening is at least partially open after the piston has been moved into the second switching position due to the positive-locking action of the medium on the piston, and furthermore, the flow opening is at least partially open. in which the inlet chamber is provided with a sensor for detecting at least one of the two switching positions, the inlet chamber is provided with an effective means for discharging excess medium when the piston is moved into the first switching position. It is characterized by the fact that it is equipped with a device that allows it to function. Further advantageous features of the invention are set out in the claims below.

0010

According to the invention, the piston is still movable in the direction towards the inlet chamber even after the flow opening has been closed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to embodiments shown in the accompanying drawings.

The oil lubrication system shown in FIG. 1 is provided with an oil stock tank 1 and a casing 2 placed on the tank. An electrically controllable pump 3 is arranged in the casing 2 , and its suction line 4 is connected to a standpipe 5 arranged in the stock tank 1 . The discharge side of the pump 3 branches out, for example, into a plurality of lines 7, which lead via further lines 8 to the inlet of a respective electrically controllable magnetic valve 6. ing. The outlet of the magnetic valve 6 is connected via a conduit 9 partially formed in the wall of the casing 2 to a distribution channel 10, the number of distribution channels 10 depending on the particular purpose of use. It is possible to provide

At least one feed line 11 is connected to the distribution channel 10, which feed line 11 is connected to a selected group of machines or selected machines in a knitting machine or some other machine (not shown). e.g. an injection nozzle or a feed nozzle 1, which can be assigned to a mechanical element etc.
2 or a similar member. in this case,
Generally, each distribution channel 1 is connected to a plurality of supply lines 11 respectively.
0 is connected.

A monitoring device 14 is also connected in each feed line 11 or between each feed line 11 and the associated distribution channel 10, these monitoring devices being integrated, for example, in a carrier plate 15. 14 is used to monitor whether oil or another particularly sufficiently incompressible fluid medium is currently flowing through the associated supply line 11 or is stationary. If only the distribution channel 10 is to be monitored, regardless of the number of supply lines 11 connected thereto, one monitoring device 14 is placed in front of the distribution channel 10, for example in the line 9. It's enough if you keep it. Each monitoring device 14 is connected to a control device 16 which is preferably electronically controllable, for example controllable by a microprocessor, and which is connected by a lead 17 to a power supply. This control device 16 controls the flow or rest phase of the oil in the supply line 11 by opening and closing the magnetic valve 6, while generating an error signal which can be used, for example, to shut off the machine to be lubricated. This type of error signal is generated, for example, if the oil is not flowing at the desired oil flow phase, or if the oil is flowing at the desired oil stationary phase, or if the oil is flowing before the desired oil flow phase begins. This is the case, for example, when the stationary phase is not signaled.

As can be seen in particular from FIGS. 2 to 7, the carrier plate 15 is formed with at least one perforation 21 in which the end opening into the distribution channel 10 has a A check valve type valve 22 is inserted, the valve 22 having a valve disc 23 pretensioned against a valve seat 25 by a spring 24 . If it is necessary to flow the oil, the magnetic valve 6 is opened to convey the oil into the supply line 11, and the oil pressure generated by the pump 3 opens the valve disc 23. On the other hand, when the magnetic valve 6 is closed, the valve disc 2
3 is pressed against the valve seat 25 by a spring 24, preventing backflow of oil. As a result, the oil remains stationary in the supply line 11 and cannot flow back, so that the supply line 11 remains filled.

The monitoring device 14 is inserted into the end of the perforation 21 formed in the carrier plate 15 facing the supply line 11 .

Oil lubrication systems of the above-mentioned type and associated monitoring devices as well as their functions are generally known from German Patent Application No. 3,624,982, German Patent Application No. 3,641,737 and are therefore not described here. Not detailed.

As shown in FIGS. 2 to 7, the casing 26 of the monitoring device 14 according to the invention has a section inserted into the borehole 21 and a section protruding from the borehole 21, for example a supply line 11. and a section suitable as a connecting nipple. Furthermore, this casing 26 also has a perforation 27 forming a flow space. This borehole 27 is essentially divided into two chambers, an inlet chamber 28 on the side facing the valve 22 and an outlet chamber 29 on the side facing the supply line 11; Setup section 21
It has a central axis 30 that extends parallel to.

A guide 31 is arranged in the borehole 27 and is advantageously formed with a bush-like section, for example with a hollow cylindrical outer circumferential surface. is not a necessary condition. This bush-like section is located within the central axis 3 in a casing section with an equivalent cross section.
It is fixed coaxially with respect to 0. The guide 31 is used as a sliding support in the guide portion 32a of the piston 32 guided therein. The guide portion 32a has a hollow space 32b open toward the inlet chamber 28 and a corresponding outer cross section, and is supported so as to be slidable within the guide 31 in parallel to the central axis 30. In this case, the movement stroke of the guide part 32a is the same as that of the closed end wall 3
2c, this end wall 32c is formed at the end of the piston 32 facing the outlet chamber 29, and its outer cross-section is larger than the inner cross-section of the guide 31. In the first switching position shown in FIG.
2c are located at opposite ends of the guide 31, whereas in the second switching position shown in FIG. 3 they rest against the stop 34 of the casing 26.

[0020] In the central region of the side wall of the guide part 32a, at least one continuous flow opening 35 is provided, through which a flowable medium can flow. This flow opening 35 is completely covered by the guide 31 in the first switching position of the piston 32 shown in FIG. 2, whereas it is at least partially covered in the second switching position of the piston 32 shown in FIG. Therefore, a passage is formed from the inlet chamber 28 through the hollow space 32b to the same part of the flow space or the perforation 27 that is formed between the guide 31 and the end wall 32c in this piston position. It turns out.

In the illustrated embodiment, the end wall 32c is also used as a carrier for the pick-up 36;
Pickup 36 as a signal generator consisting of a permanent magnet
cooperates with a sensor 37 integrated in the casing wall, for example a sensor constituted by a Hall detector, reed contact or similar element. In this case, a line 38 drawn in FIGS. 2 and 3 denotes a plane extending perpendicular to the piston movement, which plane is assigned to the piston 32 and which can be clearly distinguished by the sensor 37. The sensor 3 can be connected to the sensor 3 via a preferably electrical switching signal, ie via a schematically illustrated electrical line 39.
7 to an external switching device, in particular the control device 1 shown in FIG.
This is the plane in which the pickup 36 must move up and down in order to generate the switching signal that is supplied to the pickup 6.

As shown in particular in FIGS. 4 and 5,
The end wall 32c of the piston 32 is advantageously connected to the pickup 3.
6 and a peripheral wall 41 surrounding this notch and cooperating with the stopper 34. This circumferential wall 41 is preferably formed with a plurality of slits 42 extending parallel to the central axis 30 in FIG. 2 and adjacent to its free end. In this case, in order to obtain a relatively wide annular gap 47 and thus to enable a rapid reciprocating movement of the piston 32 without significant damping, the outer cross-section of the end wall 32c is advantageously shaped into a flow space. It is designed to be at least approximately 0.05 cm smaller than the internal cross section in the area to which the cutout 27 belongs. Furthermore, it is advantageous if a spring 43, which is designed as a non-magnetic pressure spring, is tensioned between this end wall 32c and the stop 34 (FIGS. 2 and 3).

According to FIGS. 6 and 7, a circumferentially extending flange 45 is formed in the central portion of the guide 31, and the flange 45 abuts against the shoulder 26a shown in FIGS. 2 and 3. is formed by the cross-sectional expansion of the perforation 27 and can be used to fix the guide 31 by means such as adhesive. Alternatively to this measure, the guide 31 is loosely inserted into the bore 27 and the spring 24 is made stronger than the spring 43 so that the flange 45 is held on the shoulder 26a by the force of the spring 24. It is also possible. At least one compensation passage 46 extending parallel to the central axis 30 is formed between the outer wall of the guide 31 and the inner wall of the perforation 27, and this compensation passage 46 also passes through the flange 45 to form the inlet chamber. 28 and outlet chamber 29 are connected to allow medium flow. It is advantageous if a plurality of such compensation channels 46 are provided; for example, in the embodiment shown in FIG. 7, three compensation channels 46 are arranged at an angular distance of 120 DEG from one another. In this embodiment, each compensation passage 46 has a respective perforation 4 passing through the flange 45.
6a and located between the outer wall of the guide 31 and the inner wall of the borehole 27;
In this case, the compensation channel 46 is simply designed as a groove. Therefore, above these compensation passages 46, a ring space 46b is formed which surrounds the guide 31, and as is clear in particular from FIGS. The outer diameter of the ring space 46b at this location is equal to the distance between the inner wall of the guide 31 and the outer wall of the guide 31.
It is set slightly smaller than the outer diameter dimension at a.

Next, the mode of operation of this monitoring device will be described.

After the pump 3 is connected and the magnetic valve 6 is opened, the oil is sucked up from the stand pipe 5 and pressurized into each of the conduits 7, 8, and 9. When the oil pressure in the conduit is sufficiently high, the valve 22 is opened, so that the oil pressure in the inlet chamber 28 increases. As a result, the piston 32 is lifted positive against the force of gravity or the spring 43. In this case, leakage of oil from the compensation channel 46 is prevented in that the total cross section of the compensation channel 46 is designed to be significantly smaller than the total cross section in the piston 32 that is loaded with oil. The same thing is true for the guide part 32a and the guide 31.
This also applies to the ring gap formed between When the piston 32 slides from the position shown in FIG. 2 to the position shown in FIG. Hollow space 3 from chamber 28
2b, the flow opening 35, the guide portion 32a and the casing 26
It flows into the outlet chamber 29 through the space formed between the end wall 32c and the casing 26, the annular gap 47 created between the end wall 32c and the casing 26, and the slit 42, from where the respective associated supply pipes shown in FIG. It reaches the inside of road 11.

From the flow opening 35 to the end wall 32c,
The distance to the upper edge of the guide 31 shown in FIG. The sensor 37 is set to a value that allows the sensor 37 to clearly display this position. On the other hand, the pickup 36 reaches the second switching position in which the oil can flow through the line 38.
occupies a position well above and away from the sensor 37.
This is only after a sufficiently large piston stroke has been obtained that the second switching position can also be clearly indicated. In other words, no significant oil flow occurs unless the piston 32, in response to the rising oil pressure in the inlet chamber 28, slides in a form-locking manner over a distance large enough to enable generation of a clear switching signal. cannot be admitted. When this flow opening 35 is then partially opened, the end wall 32
c can come into contact with the stopper 34 as soon as possible, so there is no need for piston movement using the frictional force between the oil and the piston 32, which now acts supplementarily. . Since the piston movement is thus carried out exclusively by form-locking, the effective overpressure in the inlet chamber 28 must be of a very small value, for example of the order of 2 bar, in order to slide the piston 32 into the second switching position. is sufficient. This means that the piston size (e.g. approximately 0.2
8 cm3), and thus the smaller the piston mass can be set, the more pronounced is the fact that there is insufficient gravity to reset the piston 32, or that the central axis 30 is, for example, in the horizontal direction. Even in such a case, the spring 43 only needs to be designed with a fairly weak spring force. Nevertheless, with such a design it is easily achieved to obtain a piston stroke of at least about 0.4 cm.

When the flow of oil is stopped by closing the magnetic valve 6, the valve disc 23, which serves as a check valve, is first closed. Then the piston 32
is caused to slide in the direction towards the first switching position by gravity or by the force of the spring 43 until the flow opening 35 is closed again. The pressure compensation in this case is the ring-shaped gap 47
This is achieved without difficulty due to the relatively wide range of The piston 32 then moves back into the first switching position shown in FIG. 2 with the flow opening 35 closed under the action of gravity or the spring 43. It should be noted that in this case, a compensating channel 46 which is additionally provided diverts excess oil present in the inlet chamber 28 into the space formed between the housing 26 and the piston 32 or from there via an annular gap 47. It is used for discharging into the outlet chamber 29.

The intended rest phase of the oil in the supply line 11 is sufficiently long that the complete backing of the piston 32 can be achieved by accepting a somewhat slow operation to reset the piston 32 to its inactive position. In order to enable the necessary pressure compensation for the stroke, it is sufficient to use a compensating channel 46 with a relatively small flow cross section. In fact, with the size of the piston 32 according to the embodiment described above, the cross-sectional area of the compensation channel 46 is approximately 0.06 cm2, whereas the annular gap 47 has a radial width of, for example, 0.05 cm or more. ing. It is thus ensured that the total cross section of the compensation channel 46 is significantly smaller than the total cross section of the annular gap 47, so that the compensation channel 4
6 has virtually no function during the opening of the valve 22 and subsequent oil flow due to its large flow resistance.

In the embodiment shown in FIGS. 8 and 9, at least one monitoring device 52 according to the invention is inserted into each perforation of the carrier plate 51, the inlet chamber 53 of which is connected to the distribution channel 54. directly connected. The monitoring device 52 has a casing 55 surrounding a flow space, in which a bush-shaped guide 56 is fixed. This guide 56 is used for slidingly guiding a piston 57 which is substantially the same as the piston 32 of the previous embodiment, and this piston 57 is formed in a hollow manner.
7 has a flow opening 58 in the side wall, and includes an end wall 59 and a pickup 60. A spring 61, which is preferably constructed as a non-magnetic compression spring, is used to reset the piston 57. Furthermore, this end wall 59 rests against the associated end of the guide 56 in the first switching position of the piston 57 shown in FIG. 8, while in the second switching position shown in FIG.
At the piston switching position, the stopper 63 of the casing 55
comes into contact with. The device is in this respect identical to the device shown in FIGS. 2 to 7, so that the representation of the sensor 37 has been omitted in FIGS. 8 and 9 for clarity of illustration.

In this embodiment, the compensation passage 4 shown in FIGS. 2 and 3 is used as a device for draining excess oil.
6, a device is provided which is arranged between the pump 3 and the distribution channel 54 and is configured, for example, as a three-way valve. In this case, the first
is connected to the distribution passage 54, a second connection to the pump 3, and a third connection to the overflow chamber 66, which includes an exhaust opening 67 and a stock tank 1. A feedback line 68 is provided which leads to.

Next, the mode of operation of the monitoring device according to FIGS. 8 and 9 will be described.

In the first switching position of the piston 57 shown in FIG. 8, the flow opening 58 is covered by the guide 56. If an oil flow phase is desired,
Magnetic valve 65 is switched to the position shown in FIG. 9 connecting pump 3 to distribution passage 54. In this case as well, as in the embodiments shown in FIGS. 2 to 7, the flow opening 58 is at least partially opened by the guide 56 (FIG. 9), and the end wall 59 rests against the stop 63. Before this, the piston 57 has to make a significant stroke movement under the pressure of the oil, that is to say in the direction towards the outlet chamber 69 before the form-fitting. The oil then flows from the distribution passage 54 through the inlet chamber 53, the hollow space of the piston 57, the annular gap 70 formed between the casing 55 and the end wall 59, and the slit 71 provided in the end wall 59, and then to the outlet. It becomes possible to flow into the chamber 69. In this case, in order to avoid a significant oil flow between the piston 57 and the guide 56, the clearance between them is set to be sufficiently small as in the embodiments of FIGS. 2 to 7. ing.

If, on the other hand, it is desired to interrupt the oil flow in the flow space of the monitoring device 52 and thus also in the associated supply line, the magnetic valve 65 is moved to the position shown in FIG. can be switched to Thus, the piston 57 is moved to the first position under the action of gravity or the spring 61.
It becomes possible to return to the switching position. In this case, the flow opening 5
In order to allow further sliding of the piston 57 even after the closure of 8, the magnetic valve which now connects the distribution channel 54 to the overflow chamber 66 allows the excess oil to escape through an annular gap 70 designed sufficiently wide. What is necessary is just to feed it back into the stock tank 1 via 65.

In the position of the magnetic valve 65 shown in FIG. 8, the magnetic valve 65 is connected to an overflow chamber 66 in order to avoid complete oil leakage of the inlet chamber 53 and the distribution passage 54 during the oil rest phase. The outlet opening of conduit 72 is well above distribution passage 54;
For example, it is arranged above the plane shown by the dashed line 74 in FIGS. 8 and 9. Additionally, an O-ring 73 surrounding the piston 57 just below the end wall 59 serves to prevent oil in the resting phase from escaping through the narrow ring space formed between the piston 57 and the guide 56. Therefore, in this embodiment there is no need to use an additional valve 22 as shown in FIGS. 2 and 3. By designing the piston 57 to an appropriate size, the amount of oil flowing into the overflow chamber 66 when discharging the oil can be controlled to be equal to or smaller than the amount of oil conveyed through each associated supply pipe for each oil flow phase. For example, it is possible to suppress it to about one-tenth. Therefore, even if the oil is drained, it is unlikely that this will result in a significant decrease in the functionality of the device.

In order to control the connection between the pump 3 and the distribution passage 54 and to effectively control the operation of draining excess oil to the first switching position during the stroke movement of the piston 57, it is configured as a three-way valve. Instead of providing a magnetic valve 65, for example two separate two-way valves or other devices may be used.

The present invention is not limited to the embodiments described above, but can be implemented in various different ways. For example, instead of using sensors as Hall generators, reed contacts or similar elements in cooperation with pickups (signal generators) made from permanent magnets,
Signal generator/sensor combinations operating inductively or optoelectronically may also be used. Furthermore, the compensation path 4 used in the embodiments of FIGS.
6 may not only be formed in the guide 31, but alternatively or in addition to this, it may also be provided in the casing 26, in which case the compensation channel 46 is not formed as a perforation. Instead, it can be formed as a groove or notch. Instead of the electrically switchable magnetic valve, a valve with another switching method or a device that can replace it may be used.

[0037] What must be emphasized here is that
The present invention is based on the illustrated guides 31, 56 and pistons 32, 57.
The invention is not limited only to combinations with , but many different further embodiments are conceivable. For example, it is also possible for the flow openings 35, 58 to be formed not in the pistons 32, 57, but in the guide. Furthermore, it is also possible to apply the oil pressure primarily to only one end wall of the piston, and to use the hollow space of the piston primarily as a sliding bearing in the pin-shaped inner guide. Furthermore, the shape of the guides and pistons does not have to be cylindrical or hollow cylindrical, and the bush-like guides 31, 51 are not included as additional separate components, but rather in the casing 26, 55 and/or the carrier plate 1.
It is also possible to construct it as an element provided directly in 5, 51.

[0038]

[Effects of the Invention] As explained above, according to the present invention,
Since the piston is able to slide further in the direction towards the inlet chamber after closing the flow opening, a pure form-fitting force transmission and thus a large piston in the opposite direction due to the small flow pressure and low flow velocity It has the effect of realizing a stroke.

[Brief explanation of the drawing]

1 is a sectional view of a known oil lubrication system for a knitting machine with a plurality of oil flow monitoring devices according to the invention; FIG.

2 is a schematic longitudinal sectional view of a monitoring device according to a first embodiment of the invention, enlarged from that in FIG. 1, in a first switching position; FIG.

3 is a schematic longitudinal sectional view of the monitoring device according to the first embodiment of the invention, enlarged from that in FIG. 1, in a second switching position; FIG.

FIG. 4 is a longitudinal sectional view, enlarged to a scale of about 5:1, of a piston of a monitoring device according to a first embodiment of the invention;

FIG. 5 is a plan view, enlarged to a scale of about 5:1, of the piston of the monitoring device according to the first embodiment of the invention;

FIG. 6 is a longitudinal sectional view, enlarged to a scale of about 5:1, of a bushing of a monitoring device according to a first embodiment of the invention;

FIG. 7 is a plan view, enlarged to a scale of about 5:1, of the bushing of the monitoring device according to the first embodiment of the invention;

8 is a schematic longitudinal sectional view of a monitoring device according to a second embodiment of the invention, enlarged from that shown in FIG. 1, in a first switching position; FIG.

9 is a schematic longitudinal sectional view of a monitoring device according to a second embodiment of the invention, enlarged from that shown in FIG. 1, in a second switching position; FIG.

[Explanation of symbols]

2 Casing 3 Pump 6 Magnetic valve 14 Monitoring device 15 Carrier plate 16 Control device 22 Valve 23 Valve disc 24 Spring 25 Valve seat 26 Casing 26a Shoulder 27 Drilling part 28 Inlet room 29 Outlet room 31 Guide 32 Piston 32a Information section 32b Hollow space 32c End wall 34 Stopper 35 Flow opening 36 Pickup 37 Sensor 40 Notch 41 Peripheral wall 42 Slit 43 Spring 45 Flange 45a Extension part 46 Compensation passage 46a　Perforation part 46b Ring space 47 Ring-shaped gap 51 Carrier plate 52 Monitoring device 53 Inlet room 55 Casing 56 Guide 57 Piston 58 Flow opening 59 End wall 60 Pickup 61 Spring 63 Stopper 65 Magnetic valve 66 Overflow chamber 68 Feed bag line 69 Outlet room 70 Ring-shaped gap 71 Slit

Claims (11)

[Claims] 1. A device for monitoring the flow of a fluid medium in a flow space having an inlet chamber and an outlet chamber, the device comprising: a casing surrounding the flow space; a guide disposed within the flow space; a piston slidably supported within the flow space by a guide; and a flow opening disposed within the flow space and configured to control flow of medium from the inlet chamber to the outlet chamber. in this case, this flow opening is closed after the piston has moved into the first switching position, whereas the positive-fitting action of the medium on the piston causes the piston to move into the second switching position. the flow opening is at least partially open after the piston has been moved, and is further provided with a sensor cooperating with the piston for detecting at least one of the two switching positions. In things, inlet chambers (28), (53)
is equipped with a device (46), (65) which is operative to discharge excess medium when the piston (32), (57) is slid into the first switching position. A device for monitoring the flow of a flowable medium in a flow space characterized by: 2. In the flow space according to claim 1, further comprising a spring (43), (61) pretensioning the piston (32), (57) into the first switching position. Device for monitoring the flow of fluid media. 3. The pistons (32), (57) have a guide part (32a) guided by a bush-like section provided on the guides (31), (56), and the guide part (32a) ) is provided with a hollow space (32b) that is open on the inlet chamber (28), (53) side and closed by end walls (32c), (59) on the outlet chamber (29), (69) side. In this case, the passage openings (35), (58) are formed in the side wall portions of the guide part (32a), and the passage openings (35), (58) are formed in the side wall portions of the guide part (32a).
3. Device for monitoring the flow of a flowable medium in a flow space according to claim 1 or 2, characterized in that opening and closing of step 8) is carried out by a bush-like section. Claim 4: Bush-shaped section and guide portion (32a)
4. Device for monitoring the flow of a flowable medium in a flow space as claimed in claim 3, characterized in that the flow space has a hollow cylindrical design. 5. The end walls (32c), (59) have a larger external cross-section than the guide (32a), and in the flow space adjacent to the bush-like section the piston (32),
(57) Two stoppers (
Device for monitoring the flow of a fluid medium in a flow space according to claim 3 or 4, characterized in that it is supported between (31), (34) to (56), (63). [Claim 6] A sensor (37
6. Device for monitoring the flow of a flowable medium in a flow space according to any one of claims 3 to 5, characterized in that a pick-up (36) is provided which cooperates with the flow space. 7. When the piston (32), (57) occupies the second switching position, the through opening (35);
Device for monitoring the flow of a flowable medium in a flow space according to claim 5 or 6, characterized in that it is configured such that only part of (58) is opened. 8. The device for discharging excess medium consists of at least one compensating channel (46),
This compensation passage (46) is formed between the outer circumferential surface of the guide (31) and the inner circumferential surface of the associated part of the casing (26), forming an inlet chamber (28) and an outlet chamber (29).
) is in fluid communication with the compensation passage (46
), the total cross-sectional area of the piston (32) being set to such a small value that its compensation function is substantially ineffective when the piston (32) is slid into the second switching position. Device for monitoring the flow of a flowable medium in a flow space according to clause 1. 9. The compensation channel (46) is constructed as a groove, notch and/or perforation formed in the inner circumference of the associated casing part and/or the outer circumference of the guide (31). Device for monitoring the flow of a fluid medium in a flow space according to claim 8. 10. The device for draining excess medium is provided with a valve (65), which is activated when the piston (57) is moved into the first switching position.
5) connects the inlet chamber (53) to the oil discharge section (72);
(66), (68), (1). Device for monitoring flow. 11. The valve (65) is configured as a three-way valve, in one position of which the inlet chamber (53) is configured as a three-way valve.
) are oil discharge parts (72), (66), (68), (1
) and in the other position the inlet chamber (53)
Device for monitoring the flow of a fluid medium in a flow space according to claim 10, characterized in that the pump (3) is connected to a pump (3).