JPS6020687B2 - Device for monitoring the level of fluid in a container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a means for making measurements, and more particularly to an apparatus for monitoring the level of a fluid within a container.

Devices made in accordance with the present invention may be incorporated with maximum efficiency into systems for automatic control of the supply, delivery and distribution of various fluids.

``The device according to the invention can be integrated into systems such as production plants of the petrochemical and food industries; fuel systems of vehicles such as car steel and aircraft; water supply systems. Devices for monitoring are already known.

This known device has a supply tube whose inlet end is adapted to communicate with the source of the source body under pressure. The outlet end of the supply tube communicates through a shroud and nozzle adapted to communicate at the monitoring level with a container containing the fluid. Furthermore, the known device has a device for indicating a change in the hydrodynamic state of the liquid flow depending on the mixing of the liquid and fluid through the nozzle.

The shroud is disposed coaxially with the nozzle and is connected to the nozzle by an inlet portion thereof. The inner surface of the shroud is the surface of the rotating body and extends toward the open end of the shroud. Said known device further comprises a control passage or duct formed in the wall of the shroud adjacent to the nozzle.

The outlet opening of the control duct opens into the interior space of the shroud, while the inlet opening of the control duct opens in the operating position of the monitoring device so that it acts on the jet ejected from the nozzle during operation of the device. is located below the monitoring level of the fluid. The display device of the known device "has a pressure pick-up and a measuring duct adapted to form a signal representative of the pressure of the fluid and to transmit this signal to the pressure pick-up.

The inlet closure of the measuring duct is arranged opposite the outlet part of the shroud and is coaxial with the nozzle (e.g.
972 King West German Patent No. 2111973, mCFI, section 1/0). When the fluid is not present at the monitored level within the vessel, a jet of liquid is ejected from the nozzle substantially transversely to the surface of the fluid within the vessel to form a laminar flow, and the jet contacts the walls of the shroud. It passes through the shroud and enters the entrance of the measurement duct as it exits the shroud. If fluid fills the container to the monitored level, this fluid enters the interior space of the shroud via the control duct and acts on the liquid jet ejected from the nozzle. The liquid flow thus assumes a turbulent character and the jet is deflected into contact with the wall of the shroud facing the outlet of the control passage, whereby the liquid bypasses the entrance of the measurement passage and flows out of the shroud. In each of the two described cases, a corresponding pressure signal is formed, which is stronger when no fluid is present at the monitored level and weaker when fluid fills the container up to the monitored level. It's well organized.

One of the prerequisites for the operation of the previously known devices is the laminar nature of the liquid jet ejected from the nozzle, so that the device only works in practice at relatively low velocities of the liquid ejected from the nozzle. It's nothing more than that.

The device thus provides for the formation of a pressure signal of relatively low value. In addition to this, when said known device is used, it is possible to accurately detect the pressure signal formed indicative of the presence of fluid in the container at the monitoring level, even upon the instantaneous or brief appearance of the fluid at the monitoring level. Subsequently, it is relatively difficult to maintain or remember for long periods of time.

Furthermore, since the operation of the known device depends on maintaining the desired direction of the liquid jet ejected from the nozzle with respect to the surface of the fluid, the known device accelerates the components of the system in which it is incorporated. is sensitive to induced movements, which acutely affects the reliability of the device's performance in maneuver systems.

This is due to the fact that during such accelerated movement the surface of the fluid is subjected to substantial vibrational disturbances, and the actual position of the fluid surface relative to the known device at the mounting location of the known device is attributable to the prescribed position. is caused by facts that are essentially different from. The object of the invention is a device for monitoring the level of a fluid in a container, comprising: a nozzle of the fluid at higher values of pressure and velocity of the liquid ejected from the nozzle;
Therefore, it is desirable to have a shroud that has a structure that monitors the fluid nozzle at higher values of the output pressure signal.

The object is a device for monitoring the fluid level in a container, in which the supply tube is adapted to have its inlet end connected to a source of liquid under a pressure higher than the surrounding sooty pressure, while its outlet end through a nozzle with a shroud adapted to communicate with a fluid at a monitoring level; and further a hydrodynamic state of said fluid stream dependent on mixing of said fluid with said fluid flow through said nozzle. In accordance with the invention, the shroud has at least one cross-section having a ratio of the maximum dimension of its internal contour to the distance between it and the exit area of said nozzle of 0. 3
a device for monitoring a fluid nozzle in a container, the front inlet part being selected such that the internal contour of its cross section surrounds the contour of the outlet area of said nozzle; achieved by. Note that the above-mentioned "hydrodynamic state" refers to a physical parameter that indicates the characteristics of a liquid flow at a certain point in time. cross-sectional area, etc.

The device for indicating a change in the hydrodynamic state of a liquid flow as described above is adapted to detect or display a change in the value of one or more physical parameters when the value of one or more physical parameters changes due to an external factor. There is. That is, the device of the present invention basically detects when the recurrent flow flowing out of the nozzle is influenced by the fluid in the container, thereby changing the hydrodynamic state of the liquid flow, by displaying the change. It is based on the principle of monitoring the level of the fluid.
With such a construction of the monitoring device, the liquid stream exiting the nozzle, when it contacts or mixes with the fluid filling the container up to the monitoring level, expands to isolate or isolate an area adjacent to the inlet portion of the shroud. shut off, thus creating a negative pressure in the area, and the liquid flow filling the entire cross-sectional area of the outlet section of the shroud.

When the liquid exits the nozzle without subsequently expanding the stream or jet, the stream or jet occupies only a relatively small portion of the cross-section of the exit section of the shroud and the inlet section of the shroud. The pressure is substantially equal to the pressure downstream of the outlet section of the shroud.

Thus, when fluid is present at the monitoring level, the hydrodynamic conditions of the liquid flow through the nozzle can be relatively easily monitored even at high values of pressure and velocity of liquid exiting the nozzle. Thereby, the usability of the monitoring device is ensured within a wide range of possible values of pressure and velocity of the liquid exiting the nozzle and for the substantially turbulent nature of the flow associated with high velocity values. Ru.

This allows the formation of an output pressure signal of a substantially higher value than is obtainable in previously known monitoring devices. Furthermore, the definition of a suction zone in the inlet section of the shroud produces a stable and pronounced change in the hydrodynamic state of the liquid flow exiting the nozzle.

If desired, this altered state may be maintained for an indefinite period of time during the subsequent absence of fluid at the monitored level. This provides the possibility of maintaining or storing the formed output pressure signal representative of the presence of fluid at the monitoring level for a long time after the instantaneous or short-term appearance of the fluid at said monitoring level.

Advantageously, the inlet section of the shroud is provided with a tube adapted to put its inlet end in communication with fluid at another monitoring level. This feature is necessary when the purpose is to monitor changes in the level of fluid in a container between two levels, and the outlet part of said shroud is in communication with one of said two monitoring levels and said A tube in the inlet section of the shroud communicates with the other monitoring level.

The incorporation of the tube makes it possible to change the hydrodynamic state of the liquid flow depending on the presence of fluid at the other monitoring level.

The incorporation of said tubes further provides the possibility of repeated monitoring of the presence and absence of fluid at both said monitoring levels.

Preferably, the inlet end of the tube is spaced from the longitudinal axis of the shroud.

The offset position of the tube makes it possible to monitor changes in the level of the fluid within a defined range of monitoring levels, which in turn makes it possible to monitor in automatic control systems for the supply, delivery and distribution of fluids. Expand the applicability of the device.

Advantageously, the tube incorporates an outlet section within it for throttling or restricting the flow rate of the fluid. Incorporating a flow restrictor within the tube allows the level of the output pressure signal to be substantially increased.

This feature further expands the applicability of the monitoring device for automatic control of fluid supply and delivery. In accordance with an embodiment of the invention, in a monitoring device, the display device comprises a pressure pick-up with a sensing or reaction element and a measuring duct, the outlet end of which is in communication with the pressure pick-up. It is also advantageous that the part is compatible with the inlet end of the measuring duct of said display device.

The communication between the inlet portion of the shroud and the pressure pick-up allows for an indication of changes in the hydrodynamic state of the liquid stream as the fluid level changes due to changes in the hydraulic pressure of the liquid stream. Further, the entrance portion of the shroud is
It is advantageous to connect the inlet end of the measuring duct via the supply pipe and the nozzle.

The passage between the inlet section of the shroud through the nozzle and the measuring duct provides an indication of the change in the hydrodynamic state of the liquid flow due to the change in liquid flow upstream of the nozzle.

Furthermore, it is advantageous for the monitoring device to have a liquid flow restrictor arranged in the supply pipe intermediate the liquid source and the inlet end of the measuring duct of the display device.

The incorporation of said flow restrictor provides for sharper changes in the overpressure or gauge pressure in the measuring duct of the display device caused by changes in the hydrodynamic state of the liquid flow, and thus improved monitoring accuracy. do.

Furthermore, the display device comprises a pressure pick-up with a responsive element, the outlet end of which is in communication with the pick-up, while the inlet end is arranged coaxially with respect to the nozzle facing the outlet portion of the shroud. According to an embodiment of the invention, in a monitoring device having a measuring duct with
It is also advantageous for the inside of the outlet section of the shroud to be provided with a plurality of helically extending ribs adapted to impart a tangential velocity component to the flow exiting the nozzle.

The arrangement of the helical ribs ensures an increase in the total pressure at the outer edge of the liquid flow and a decrease in the total pressure adjacent to the fly line of the shroud.

This feature further improves the reliability of the level monitoring operation by further reducing the value of the pressure signal when fluid appears at any monitored level. Furthermore, an indicating device comprises a pressure pickup having a responsive element, an outlet end of which is in communication with the pressure pickup, and an inlet end of which is disposed coaxially with respect to the nozzle, facing the outlet portion of the shroud. In a monitoring device with a measuring duct, it is advantageous, according to an embodiment of the invention, that the outlet part of the shroud extends at a similar dominant angle to the longitudinal axis of the nozzle.

Such a relative arrangement of the shroud and nozzle directs the flow downstream of the outlet section of the shroud laterally relative to the inlet end of the measurement duct as fluid emerges at any one of the monitoring levels. enable you to lead.

This feature reduces the value of the pressure signal even further in the above case, thereby further improving the reliability of the operation of the monitoring device.

the display device comprises a pressure pickup comprising a responsive element;
An embodiment of the present invention in a monitoring device having a measuring duct whose outlet end communicates with the pick-up and whose inlet end faces the outlet portion of the shroud and is spaced from the bag line of the nozzle. Accordingly, it is advantageous for the outlet section of the shroud to extend coaxially with respect to the nozzle.

Such relative alignment of the shroud outlet section and the nozzle allows an additional signal to be obtained in the form of positive gauge pressure or positive overpressure indicative of the presence of fluid at the monitoring level downstream of the shroud outlet section. .

A monitoring device constructed in accordance with the present invention allows for reliable monitoring of the level of fluid within a wide range of pressure and velocity values of the liquid stream exiting the nozzle, and guarantees a very high level output signal over the entire range.

Further, a monitoring device constructed in accordance with the present invention is capable of maintaining a signal indicative of the presence of fluid at a monitoring level downstream of the shroud for any required period of time, including the time of change in fluid level within a specified range. enable.

One monitoring device constructed in accordance with the present invention allows for the simultaneous acquisition of multiple signals representative of the presence and absence of fluid downstream of the shroud and upstream of the pipes conveying to other levels.

By measuring the total static pressure of the liquid flow, it is also possible to obtain an electrical signal, a positive gauge pressure signal and a negative pressure signal simultaneously. The monitoring device disclosed herein is relatively simple and does not require much expense to manufacture.

Several embodiments of the invention will now be described with reference to the accompanying drawings. Referring now to the accompanying drawings, the apparatus disclosed herein is intended for monitoring the height or level of fluid within container B (FIG. 1).

This monitoring device indicates changes in the hydrodynamic conditions of the liquid flow through the supply pipe 1 (FIGS. 1 and 2), the enclosure or shroud 3, the ring 11, and the jet nozzle 2. In other words, it has a display device 4. The supply tube 1 is adapted to communicate at its inlet end la with a source of liquid (not shown) at a pressure higher than that of the surrounding soot. The tube 1 has its outlet end connected to a jet nozzle 2 coaxial with the tube 1.
It is located adjacent to. The shroud 3 has an inlet section 8 , a neck section 10 and an outlet section 9 and is arranged coaxially with respect to the nozzle 2 and the coupling tube 1 . Tube 1 is
Via the nozzle 2, the shroud 3 is in communication with a container B which contains a fluid and is filled to level C-C. Nozzle 2
The axis of is coincident with the longitudinal axis of shroud 3, and 0-○
It is shown with. As already mentioned, the monitoring device is equipped with a display device 4 for displaying changes in the hydrodynamic state of the liquid flow through the nozzle 2, which changes indicate that the liquid flow is mixed with or assisted by the fluid in the container B. Caused by touching.

The display device 4 has a flexible diaphragm 5 arranged perpendicularly to the longitudinal axis 0-0 of the monitoring device and located opposite the shroud 3 and coaxially therewith. The diaphragm 5 is designed to interact with the fluid flow through the nozzle 2 at the same time that the hydrodynamic conditions of the fluid flow change as a result of said flow coming into contact with or mixing with the fluid in the container B. .

The diaphragm 5 has an opening □6 aligned with the longitudinal rattan line ○-0.

The gate 6 is adapted to allow the liquid flow exiting the nozzle 2 to pass therethrough. An electric strain gauge 7 (FIG. 3) is attached to the outside of the diaphragm 5, and the strain gauge 7 is connected to a power source (not shown) and is connected to the diaphragm by sending a signal obtained from its changing resistance. It is designed to react to the deformation of 5.

The strain gauge 7 has any suitable construction known per se. Furthermore, the strain gauge 7 is connected to a device (not shown) adapted to receive the signal and display it. The device may also be of any structure known per se and suitable for the purpose. The shroud 3 has an inlet section 8 (FIGS. 1 and 2).

The inlet section 8 is cylindrical and, as shown in FIG.
The aim is to maintain the stability of the changes in the hydrodynamic state of the flow due to the presence of fluid in container B at the monitored level C-C. The shroud 3 further has a frustoconical outlet section 9, which ensures the stability of changes in the hydrodynamic state of the flow due to wide variations in the pressure and velocity of the liquid exiting the nozzle 2. It is like that.

Furthermore, the shroud 3 has a neck section 10 formed as a cylindrical pipe. The neck section 10' serves as a connection or transition between the inlet section 8 and the outlet section 9. In its cross section, The neck portion 1 has a closed circular contour.According to the invention, the ratio of the maximum dimension of the internal contour of the capital portion 10 to the distance from the outlet area of the nozzle 2 to the neck area is less than 0.35:1. To be elected.

The ratio of the two dimensions is absolutely necessary in order to guarantee contact of the liquid stream exiting the nozzle 2 with the capital wing 0 along the entire contour of the cross-section of the neck wing 0.

Such contact occurs following contact or mixing of said liquid stream with the fluid filling container B. According to the invention,
The inlet section 8 of the shroud 3 has an internal contour in its cross section that surrounds the contour of the outlet area of the nozzle 2 and thus defines an internal space of the inlet section 8 and isolates this space from the interior of the container B. The structure is designed to do so.

The monitoring device furthermore has a ring 11 on which a display device 4 can be attached. The connecting strips 2 are connected to the shroud 3 via the outlet section 9 of the shroud 3 and angularly spaced apart from each other with uniform spacing along the outer edge of the ring 1. In the example, the connecting strip turtle 2 is formed integrally with the ring 11. The connecting strip 12 forms a boat 13 that establishes a communication between the interior of the shroud 3 and the vessel B.

The Fuji line ○-0 of the monitoring device being explained extends horizontally.
The angle defined by the axis ○−○ and the surface of the fluid is
If necessary for the optimum arrangement of the monitoring device in the container B, it can be varied arbitrarily within a considerable range.

The only mandatory condition is that in any case of the arrangement of monitoring devices, it is not guaranteed that fluid will enter the shroud from the bell, no matter where the level to be monitored is located in vessel B. This means that it should not be.
By virtue of the shroud 3 having a cross-sectional shape defined such that the ratio of the maximum dimension of the profile to the distance of the shroud 3 from the exit area of the nozzle 2 is less than 0.35:1, and furthermore, the inlet portion 8 by enclosing the contour of the outlet area of the nozzle 2 by the internal contour of its cross-section, so that when the flow of liquid exiting the nozzle 2 comes into contact with the fluid in the container B, the "inlet section 8" from the container B is Reliable isolation of the interior space is guaranteed.

This results from the fact that in this case the liquid flow contacts the neck part 10 along the entire contour of the cross section of the capital part 10.Therefore, there is a pressure in the internal space of the inlet part 8 that is higher than the pressure in the container B. A pressure value is generated that corresponds to the plexus pressure of the low liquid flow, whereby the resulting change in the hydrodynamic state of the liquid flow is given a stable characteristic, such a characteristic can be relied upon for said change. In a second embodiment of a fluid level monitoring device, schematically shown in FIG.
The Atsushi tube 1 with the nozzle 2, the shroud 3 and the display device 4, i.e. all the components designated with numbers 1 to 13, are:
It has the same structure as those illustrated and explained in FIGS. 1, 2, 3, and 4.

However, in the embodiment shown in FIG. 5, the inlet section 8 of the shroud 3 is provided with a tube 14, which has an inlet end for fluid filling the container B to another monitoring level D-D. It is made to pass through the lotus.

On the other hand, the shroud 3 is adapted to open its outlet portion 9 to the fluid in the container B at the monitored level C--C.

The outlet section 9 of the shroud 3 and the inlet end of the tube 14 are respectively adapted to fluid monitoring levels C-C and D-D.
can also be located in different containers (not shown).

In the embodiment of the monitoring device shown in FIG. 5, the axis 0-0 of the device is oblique.

However, the device of this embodiment can function with high reliability by extending the marimark line ○-0 at any angle with respect to the horizontal plane. tube 1
4 extends 01 times with respect to the supply pipe 1, and cooperates with it to define an annular duct 15. As shown in Figure 5,
There are four openings in the upstream end wall of the inlet portion 8 of the shroud 3.
16 are formed and these closures 16 are adapted to establish a communication between the inlet section 8 of the shroud 3 and the annular duct 15.

These openings 16 are angularly spaced from each other at a uniform distance along said end wall of the inlet section 8. The described embodiment of the monitoring device is such that the liquid stream leaving the nozzle 2 arrives from the vessel B through the outlet part of the shroud 3 or through the tube 14, i.e. from level C-C or from level D-D. The monitoring device monitors the level of the fluid at both levels, since it is configured to be able to come into contact with the fluid entering the interior space of the inlet portion 8 of the shroud 3. The sequence and value of the respective signals of the display device 4 are determined in this case by the sequence of appearance of the fluid at levels CC and DD.

In a third embodiment of the monitoring device, schematically illustrated in FIG. The structure is similar to that shown and described in FIGS. 1, 2, 3, and 4.

In the embodiment shown in FIG. 6, the inlet section 8 of the shroud 3 is provided with a tube 17 which extends perpendicularly to the longitudinal axis 0-0 of the shroud 3 and extends upwardly therefrom. protrudes to.

The tube 17 is adapted to have its inlet end 17a in communication with another monitored level of fluid E-E.

The inlet end 17a is therefore spaced from the longitudinal axis ○-○ of the shroud 3. The fluid monitoring level E-E with which the monitoring device is arranged as shown in FIG. It is located above Bell C-C. 2 monitoring levels C-
At any point in the fluid level between C and E-E,
Since the supply of fluid into the outlet section 9 of the shroud 3 remains virtually unchanged, the monitored levels C-C and B of the fluid in the container B
-E while the fluid level changes between these two monitoring levels C-C and E-E.
further improves the stability of the hydrodynamic state of the mixed flow of liquid in the outlet section 9 of.

The above feature of this monitoring device is that the inlet end 17a of the technical pipe 17 is
It is also present when located below the outlet section 9 of the shroud 3, as will be explained later. In a fourth embodiment of a device for monitoring the level of fluid in a container B, schematically shown in FIG.
, shroud 3 and display device, namely numbers 1, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 1
All components designated by 7 are of similar construction to that illustrated and described with reference to FIG. The difference is
The technique tube 17 has a downwardly directed inlet end 17a.
In the embodiment of the monitoring device shown in FIG.
7 has a fluid flow rate restriction device 18 installed therein.

Once the fluid in container B reaches the monitoring level C-C, the liquid exiting from nozzle 2 is mixed with this fluid;
The formation of a conical flow from the nozzle 2 in contact with the neck portion 10 of the shroud 3 creates a suction force due to vacuum in the inlet portion 8 of the shroud 3, which improves the hydrodynamics of the liquid exiting the nozzle 2. The situation has clearly changed,
When this is detected by the display device 4, even if the fluid level drops from this monitoring level C-C, the display device 4 continues to output the same signal, and the reason is that the inlet end 17a of the technical pipe 17
This is because the fluid continues to be introduced into the inlet portion 8 of the shroud 3 by the suction force due to the aforementioned reduced pressure, and a conical flow is maintained from the nozzle 2 in contact with the neck portion 10 of the shroud 3. be. However,
Technological turtle? If the cross section of the inlet end turtle Ta is too large, the fluid cannot be sucked in due to the reduced pressure in the inlet portion 8 of the shroud 3, and the above-mentioned conical flow may be lost. Limiting device 18' fluid level is at monitoring level F-F
to ensure that fluid is always introduced into the inlet section 8 of the shroud 3 until the fluid level drops from C-C to F-F.
This is provided to ensure that the display device 4 outputs the same signal as it does when it is in use. In the fourth embodiment described, the fluid flow restriction device 18 includes:
A stub fitted within the inlet end 17a of the tube 17 is in the form of a constriction tube, the diameter of which is smaller than the inner diameter of the tube 17.

However, said restriction device 18 may be of any other known construction suitable for that purpose. In the embodiment shown in FIG. 7, the inlet end 17a of the tube 17 is spaced from the longitudinal axis of the shroud 3. This is the 6th
Rotate the shroud 3 shown in the figure around the sea bream line ○-○, direct the technique tube 17 vertically downward, and turn the inlet end 17a
is thereby located in vessel B at monitoring level F-F. The configuration of the monitoring device with the technical tube 17 pointing downwards means that the nozzle 2 is in a downward position until the fluid actually reaches the higher one of the two monitoring levels, i.e., level C1C in the described embodiment. It is advantageous in applications where it is desired to delay the change in the hydrodynamic state of the liquid stream exiting the /spool 2, i.e. when the fluid level initially reaches F-F The situation does not change at all, because there is no fluid inside the shroud 3, and the liquid coming out of the nozzle 2 just goes out through the opening □6 of the display device 4 without being diffused. , the level of the fluid rises to C-
When reaching C, a conical flow is formed from the nozzle 2 in contact with the shroud 3 as described above, reducing the pressure in the inlet section 8 and changing the hydrodynamic state of the liquid exiting the nozzle 2. A sudden change occurs and this change is clearly detected by the display device 4. Once this state is reached, fluid is drawn into the inlet portion 8 from the inlet end turtle 7a of the tube 17 as described above. By this, even if the fluid level drops from C-C, the display device 4 continues to output the same signal until it reaches F-F.In other words, no signal is emitted at the initial level of F-F. , C-C, the signal is not emitted for the first time, and the embodiment shown in Fig. 7 can be used for such applications.In the embodiment shown in Fig. 7, The inlet end 17a of the branch pipe 17 is connected to the same container B as the outlet section 9 of the shroud 3.
Located within.

However, in other applications, the outlet section 9 of the shroud 3 and the inlet end 17a of the tube 17 may be placed in different containers (not shown). The incorporation of flow restriction device 18 enhances the desired passage of signals indicative of changes in the hydrodynamic state of the liquid flow.

This is because a reduction in the flow rate of the fluid correspondingly reduces the energy required to impart to it the necessary velocity when mixing with the liquid stream exiting the nozzle 2, whereby the flow rate increases. and the signal is enhanced accordingly. In the fifth embodiment shown in FIG.
, 2, 3, 8, 9, 10, and 17 are of the structure shown and described in FIG.

In the embodiment shown in FIG. 8, this is also produced by the mixing of the liquid stream exiting the nozzle 2 with the fluid in the container B.

A device 4a is provided for indicating changes in the hydrodynamic state of the liquid stream. The display device 4a has a pressure receiver or pick-up 19 adapted to react to changes in the pressure within the interior space of the inlet section 8 of the shroud 3 as the hydrodynamic conditions of the liquid stream change.

The pick-up 19 has a pressure-responsive element and has any structure known per se suitable for that purpose. The display device 4a further indicates the source of the pressure to be measured, namely the interior space of the inlet section 8 of the shroud 3 and the pressure pickup 1.
A measuring duct 20 for lotus communication is provided between the 9 and 9.

In the embodiment shown in FIG. 8, the interior space of the inlet section 8 of the shroud 3 communicates with the inlet end of the measuring duct 20. In the embodiment shown in FIG.

The connection between the inlet section 8 of the shroud 3 and the inlet end of the measuring duct 20 allows easy and reliable monitoring of the presence of fluid at any one of the two monitoring levels C-C and F-F. Make it.

This is because in this embodiment the monitoring device does not require additional sources and signal conversion means. In the sixth embodiment shown in FIG. 9, the numbers 1, 2, 3, 8, 9, 1
All components designated with 0, 17, 18 are
It has the same structure as shown and explained with reference to FIG. 8 and FIG.

In the embodiment shown in FIG. 9, the monitoring device
It has a device 4b for indicating a change in the hydrodynamic state of the liquid stream exiting the liquid stream. The display device 4b has a pressure pick-up 21 with pressure-responsive means.

The pressure pick-up 21 detects the liquid in the supply tube 1 caused by the change in the hydrodynamic state of the liquid stream, caused by the mixing of the liquid stream exiting the nozzle 2 with the fluid at the monitoring level C-C in the container B. The purpose is to display changes in pressure. Pick-up 21 may be of any suitable construction known per se.

The display device 4b of the embodiment of FIG.
It has 2.

In this embodiment, the inlet section 8 of the shroud 3 mates with the inlet end of the measuring duct 22 via the supply tube 1 and the nozzle 2.

Since a change in the hydrodynamic state of the liquid stream is accompanied by a change in the velocity of the liquid stream through the nozzle 2 and therefore a change in the static pressure of the liquid stream upstream of the nozzle 2 in the tube 1, the supply tube 1 and the nozzle 2 and between the inlet portion 8 of the shroud 3 and the inlet end of the measuring duct 22 simultaneously with an indication of a change in the hydrodynamic state of the liquid flow due to a change in positive gauge pressure or An indication of the change in pressure within the inlet section 8 of the shroud 3 is achieved independently of the change in .

In the embodiment shown in FIG. 9, a liquid flow rate restriction device 23 is further incorporated.

The restriction device 23 is attached to the supply pipe 1 between the inlet end of the measuring duct 22 and the liquid supply source. The restriction device or shark flow element 23 is in the form of a short tube whose internal bore diameter is smaller than the internal diameter of the supply tube 1. However, the restriction device 23 may be of any other suitable construction known per se.

The incorporation of a flow restriction device 23 upstream of the inlet end of the measuring duct 22 increases the dependence of the measured pressure on the hydrodynamic state of the liquid flow through the nozzle 2 and also increases the dependence of the measured pressure on changes in the liquid pressure in the liquid source. Reduce pressure dependence.

In a seventh embodiment of the fluid level monitoring device illustrated in FIG.
All components designated 2, 13, 17, 18 have the structure illustrated by FIG.

The embodiment shown in FIG. 10 has a device 4c for indicating changes in the hydrodynamic state of the liquid flow through the nozzle 2. The embodiment shown in FIG.

The device 4c has a pressure receiver or pickup 24 adapted to indicate changes in the total pressure of the liquid stream as the hydrodynamic conditions of the liquid stream change. pressure pickup 24
may be of any suitable structure known per se. The display device 4c further includes a measurement duct 25. The duct 25
is adapted to supply measuring pressure to a suitable pressure pickup 24 by its outlet end 25a. The inlet end 25b of the measuring duct 25 is arranged coaxially with respect to the shroud 3 and the nozzle 2 and facing the outlet part 9 of the shroud 3. The inlet end 25b is supported by the ring 11 with the aid of a bracket 26 of any suitable construction known per se. In the embodiment shown in Fig. 1, two ribs are arranged inside the exit portion of the shroud 3.

These ribs are integrally formed with the outlet section g of the shroud 3 and extend in a spiral manner. I love these ribs, container B
The purpose is to provide a soybean fast brewing component to the flow resulting from the mixing of the fluid inside the nozzle 2 and the liquid exiting from the nozzle 2. The end part 7a of the spiral rib 2 has a height that gradually decreases, and smoothly merges with the inner wall of the outlet part of the shroud 3. The provision of the helical rib crab 7 "guarantees the redistribution of the energy of the mixed flow and thus
Although the total pressure in the measuring duct 2 is reduced, the pressure drop indicated by the pick-up 241 is thereby increased, which improves the response and reliability of the performance of the monitoring device.

In the eighth embodiment shown in Fig. 8, the supply pipe with the nozzle 2 also has an inlet part box ``neck part turtle 8'' with a flow restriction device wealth 8 and a pressure pick-up monument & and the inlet end. Measuring duct 2 with an outlet end, i.e., all components indicated with numbers 6 and 6 are the same as those illustrated and explained with fig. Has a structure.

The embodiment shown in FIG. 19 has a shroud 28 adapted to monitor level C-C of the fluid in container B.

The shroud 28 is shown in FIGS.
FIG. 7 has an inlet portion 8 and a neck portion Q having the same structure as shown and described in FIGS. 9 and 10.
The shroud 28 has a tapered portion 29 and a cylindrical portion 30, which are located coaxially and are arranged so that the bream line of the monitoring device is
have a common axis that coincides with 0. The portion 29 of the shroud 28 is adapted to form a mixed flow resulting from the mixing of the fluid in the container B and the liquid flow exiting the nozzle 2. Shroud 28' and longitudinal axis ○
It has an outlet section 3 which extends obliquely to -0. The outlet section 31 is adapted to deflect the mixed stream as it enters the vessel B. The monitoring device further includes a measuring duct 25 opposite the outlet section 31 of the shroud 26.
It has a shroud 32 for supporting the inlet end of the.

By arranging the outlet section 38 of the shroud 2 at an angle with respect to the longitudinal axis ○-0 and with respect to the inlet end of the measuring duct 25 coaxial with the shroud 2, the flow of water flows from the inlet end of the measuring duct 2S. deflected away.

Therefore, as the liquid jet emerging from the nozzle 2 also mixes with the fluid coming into the interior space of the shroud 28 from one of the monitoring levels F-F and C-C, the total pressure in the measuring duct 26 increases. A larger reduction occurs. Therefore, the pressure drop displayed by the Big Up 2 is increased - thereby improving the response and performance reliability of the monitoring device.

In the ninth embodiment of the fluid level monitoring device shown in the electrical panel diagram, there is also a supply tube 17 with a nozzle identification, a shroud 3 and a restrictor turtle 8, i.e. number L 2,
3, 8, 9, 108 All components denoted by 17, 18 have the same characteristics as illustrated and described in Figures 3, 8, 9, 108 and 9.

In the embodiment shown in FIG. 2, the display device d has a pressure receiver or pick-up 33 with a reactive element, which pick-up 33 detects the fluid in the container B and the nozzle 2 at the monitoring level C-C. It is adapted to display the total pressure of the liquid stream following mixing with the passing liquid stream. The pressure pickup 33 may also be of any suitable construction known per se.

The display device 4d has a measuring duct 34 adapted to convey the pressure to be measured to the pick-up 33. The outlet end 34a of the measuring duct 34 communicates with the pressure pickup 33, while its inlet end 34b is positioned so as to face the outlet section 9 of the shroud 3, and is spaced from the wire ○-0 of the nozzle 2. In other words, it is biased towards one side.
In the embodiment shown, the outlet part of the shroud is arranged coaxially with respect to the nozzle 2. Alternatively, the measuring duct 34 may have a plurality of inlet ends (not shown) spaced from the axis ○-○.

A plurality of symmetrically arranged inlet ends can also be combined, so that the inlet end of the measuring duct 34 is ring-shaped (not shown). The inlet end 34b of the measuring duct 34 is supported by the shroud 3 with the aid of a bracket 36.

The coaxial arrangement of the outlet section 9 of the shroud 3 and the nozzle 2 in an embodiment in which the inlet end of the measuring duct 34 is located offset from the mark line ○-0, the outlet of the shroud 3 is indicated as a signal of positive gauge pressure. The presence of liquid flow at the periphery of the portion 9 allows monitoring of the appearance of the fluid.

The operation of the monitoring device according to the invention illustrated in FIGS. 1 and 2 is as follows.

In the example, the fluid in container B whose level is to be monitored is a liquid.

In order for the monitoring device to work, it is necessary to supply a liquid from its source into the supply pipe 1 under a pressure greater than the pressure of the surrounding soot in the container B.

When there is no fluid at level C-C to be monitored,
The liquid jet ejected from the nozzle 2 into the interior of the shroud 3 does not impinge on the shroud 3 and practically does not change its shape and cross-sectional diameter. The jet thus passes through the closure of the diaphragm 5 without contacting it. The diaphragm 5 is therefore unaffected by the liquid flow, so that the electrical resistance of the strain gauge 7 does not change. When the fluid appears at the monitoring level C-C, there is contact and mixing between the fluid and the liquid ejected from the nozzle 2.

As a result of this mixing, a change occurs in the hydrodynamic state of the liquid stream, so that the jet now comes into contact with the wall of the outlet section 9 and occupies its entire cross section.

The liquid stream therefore contacts the diaphragm 5 and such contact causes the diaphragm 5 to deform. As a result of the deformation of the diaphragm 5 a change occurs in the electrical resistance of the strain gauge 7, which is measured by the receiver of the signal sent by the strain gauge 7, and the change in the measured resistance is determined by the fluid dynamics of the liquid flow. used to indicate changes in the state of the

Upon contacting the diaphragm 5, the liquid stream is ejected through the entrance 6 and the boat 13. As the liquid mixes with the liquid stream ejected from the nozzle 2, the jet then follows the entire contour of the neck portion 10 and shrouds. 3, the interior space of the inlet part 8 becomes isolated and a reduced change occurs there, which is equal to the static pressure of the liquid flow.

The higher the injection velocity of the liquid from the nozzle 2, the lower the variation in the inlet section 8 of the shroud 3. When the fluid level in the container 8 subsequently falls below the monitoring level C-C, the hydrodynamic state of the fluid flow is such that a reduced pressure is maintained in the inlet section 8 of the shroud 3. It does not change. Therefore, the nature of the interaction between the diaphragm 5 and the fluid does not change, so that the changed resistance of the strain gauge 7 is maintained. This changed resistance represents fluid reaching monitoring level C...C. A stable change in the hydrodynamic state of the liquid flow is achieved when the ratio of the maximum dimension of the contour of the mass part 10 to the distance from the exit area of the nozzle 2 to the metropolitan area is less than 0.35:1.
・Occasionally occurs.

To return the monitoring device to its initial layer, it is only necessary to interrupt the supply of liquid from the pressurized liquid source to the supply tube 1. In the embodiment shown in FIG. 5, the contacts for activating the device are similar to the contacts for activating the embodiment described with FIGS. 1 and 2 in the supply pipe 1. This is done by starting the supply of liquid under pressure to the Monitoring level C-
When no fluid is present at C, the liquid jet ejected from the nozzle 2 does not change its shape in the shroud 3 and passes through the closure 6 without contacting the diaphragm 5.

This is the same as in the embodiment described with reference to FIGS. 1 and 2. When liquid appears at either monitoring level C-C or D-D, a change occurs in the hydrodynamic state of the liquid flow.

Depending on the degree of inclination of the shroud 3 and whether the monitored levels of fluid are in the same or different containers, the sequence of appearance of the fluid in the monitored levels is correspondingly different.

If the fluid first appears at monitoring level C-C, then
The change in the hydrodynamic state of the liquid flow is the same as the corresponding change in the operation of the monitoring device illustrated in FIGS. 1 and 2.

If fluid first appears at monitoring level DD, it flows into the interior space of the inlet section of shroud 3 via passage 15 and closure 16 of tube 14.

As a result, the liquid stream exiting the nozzle 2 comes into contact with and mixes with the fluid, and changes similar to those already described with respect to the operation of the device illustrated in FIGS. 1 and 2 occur in the liquid stream. produced in a dynamic state.

In this case, the monitoring device detects that "the initial condition in which the liquid jet ejected from the nozzle 2 does not back-erode the wall of the shroud 3" when the level of the fluid falls below the two monitoring levels C-C and D-D. Recover.

The representation of changes in the hydrodynamic state of the liquid flow is shown in Figures 1 and 2.
This is accomplished in a manner similar to that already described with respect to the operation of the device illustrated in the figures. In the embodiment shown in FIG. 6, the initiation of operation, the change in the hydrodynamic state of the liquid flow and the representation of this change are shown in FIGS. 1, 2, 3, 4 and 5. In the embodiment of FIG. 6, branch pipe 17 is provided so that, for example, as the level of fluid in container B rises, When the monitoring level C-C is reached, the fluid dynamic state of the liquid jet does not change to the maximum limit, and the fluid level continues to rise until the monitoring level E-E' is reached. The change in dynamic state reaches its maximum limit.

Therefore, the monitoring function of the monitoring device of the embodiment shown in FIG. 6 is different from that shown in FIGS. The functions of the embodiment shown in FIG. 6 will be further explained as follows. When no fluid is present at the monitoring level C-C upstream of the outlet section 9 of the shroud 3, the liquid jet ejected from the nozzle 2 does not contact the wall of the shroud 3 and exits through the entrance 6 of the diaphragm 5. go.

When the fluid appears at the monitoring level C-C, it mixes with the liquid and causes a change in the hydrodynamic state of the liquid flow, causing the liquid jet to spread out.

On the other hand, the interior space of the inlet section 8 of the shroud 3 is suitable for a second monitoring level E-E, where no fluid is present.

Therefore, the pressure in the internal space will only decrease slightly and therefore the signal obtained from the display device 4 will not reach its maximum value. -E, the differential pressure between the pressure at the monitoring level and the pressure in the internal space of the inlet section 8 of the shroud 3 increases step by step, and correspondingly the output signal of the display device 4 increases in its value.

When the fluid level falls below the monitored level E-E at the inlet of the inlet end of the tube 17, the output signal of the display pupil 4 decreases again.

Then, when the fluid level falls below the shroud 3, the hydrodynamic state of the fluid flow changes and the output signal of the display device 4 changes correspondingly. In the case of the embodiment shown in FIG. 7, the initiation of operation, the change in the hydrodynamic state of the liquid flow and the indication of this change are the same as those already described with respect to the operation of the device shown in FIG. It is. 7th
In the illustrated embodiment, the change in the hydrodynamic state of the liquid flow and therefore that of the flow also occurs when the fluid level rises to the monitoring level C-C.

In this case, the restriction of the flow rate of the fluid drawn from the other monitoring level F-F via the technical pipe 17 is such that the effective energy of the liquid stream ejected from the nozzle 2 increases the energy of the mixed stream of liquids. Therefore, the level of the output signal of the display device increases.When the fluid level falls below the monitoring level C-C, the fluid power of the flow of liquid through the nozzle 2 increases. The physical state and the level of the output signal of the display device 4 do not change until the fluid is located at the other monitoring level F-F.The monitoring device of the embodiment shown in FIG. has a different downwardly extending branch pipe 17, thereby producing the supervising function.

The function of the branch pipe 17 in FIG. 7 is similar to the function of the branch pipe 17 in the embodiments shown in FIGS. 8 to 12.
For the embodiment illustrated in Figure 8, the initiation of operation of the device, the change in the hydrodynamic state of the liquid flow, and the change in the level of the output signal indicative of this change are shown in Figure 8. are the same as those already described with respect to the operation of the equipment;
Changes in the hydrodynamic state of the liquid flow are indicated by changes in the pressure within the interior space of the inlet section 8 of the shroud.

When the fluid is located both at the two monitoring levels C-C and F-F, and after a drop in the fluid level from the monitoring level C-C, the "fluid is simply When located only on level F-F, the pressure pickup...9 indicates the negative pressure in the interior space of the inlet section 8.

On the other hand, if the fluid level has not reached the monitoring level C-C and the fluid has reached two monitoring levels C-C and F-F
When both are absent, the pick-up 19 indicates the equality of the pressure values in the interior space of the inlet section 8 of the shroud 3 and upstream of the outlet section 9. In the case of the embodiment shown in FIG. 9, the start of operation of the device, the change in the hydrodynamic state of the liquid flow due to a change in the fluid level and the corresponding change in the pressure in the interior space of the inlet section 8 of the shroud 3. The changes are the same as those already described in connection with the operation of the apparatus illustrated in FIGS. 7 and 8. As a result of the change in the hydrodynamic state of the liquid flow through the nozzle 2, the liquid pressure in the supply tube 1 upstream of the nozzle 2 changes.

If the liquid does not mix with the fluid after it emerges from the nozzle 2 and the liquid jet does not contact the wall of the shroud 3, the pressure in the supply pipe 1 upstream of the nozzle 2 will be:
Effectively equal to the pressure at which the liquid is delivered from its source.

Monitoring level C1C upstream of the outlet section 9 of the shroud 3
Following the change in the hydrodynamic state of the liquid flow caused by the appearance of fluid at and the consequent opening of the liquid jet, the pressure in the supply pipe 1 upstream of the nozzle 2 decreases.

The change in pressure in the supply tube 1 is indicated by the pressure pickup 21, and the flow restrictor 23 prevents a partial recovery of the pressure indicated by the pickup 21, but acts as an amplifier of the signal. For the embodiment shown in FIG. 10, the initiation of operation of the apparatus, the change in the hydrodynamic state of the liquid flow as the liquid level changes, and the change in the output signal level are the same as in the case of the apparatus illustrated in FIG. Similar in operation to those already described.

When there is no fluid at both monitoring levels C-C and F-F,
and before the appearance of the fluid at the monitoring level C-C downstream of the outlet section 9 of the shroud 3, the liquid jet ejected from the nozzle 2 covers the entire area between the outlet section of the nozzle 2 and the inlet end of the measuring duct 25. It does not practically change its direction and shape over distance. Therefore, the pressure pickup 24
will in this case respond to the absence of fluid with a maximum output signal. As the fluid emerges at the monitoring level C-C downstream of the outlet section 9 of the shroud 3, the liquid stream ejected from the nozzle 2 mixes with the fluid and the liquid jet spreads out, whereby the static pressure and the flow rate increase according to said mixing. reduce below their respective values before.

The output signal of pressure pickup 24 therefore decreases in value, thus indicating a change in the hydrodynamic state of the liquid flow. As the mixed flow diverges towards the wall of the outlet section 9 of the shroud 3, it contacts and cooperates with the helically extending ribs 27.

As a result of contact with the helical rib 27, the flow is imparted with a tangential component of its velocity, whereby the energy of the liquid stream is redistributed and the axial component of the velocity of the flow adjacent to its axis is reduced to its value. decreases in As a result of said reduction in the axial component of the flow rate when the monitored level F is present, the pressure displayed by the pickup 24 is further reduced and the response of the monitoring device is correspondingly improved. .

In the case of the embodiment shown in FIG.
Similar to those already described with respect to the operation of the device shown in the figures.

Prior to mixing of the liquid flow through nozzle 2 with the fluid at monitoring level C-C, pressure pickup 24 sends a maximum signal. The signal is acted upon by the total pressure of the liquid jet ejected from the nozzle 2. The liquid ejected from the nozzle 2 mixes with the fluid, and the inlet end of the measuring duct 25 is located outside the flow of liquid, which is deflected at an angle with respect to the inlet part of the measuring duct 25.

The pressure exhibited by the pick-up 24 is therefore reduced, which means that the response of the monitoring device is correspondingly improved.

In the case of the embodiment shown in FIG. 12, the initiation of its operation, the change in the hydrodynamic state of the liquid flow, are similar to those already described with respect to the operation of the device illustrated in FIG.

o Before the liquid stream exiting the nozzle 2 mixes with the fluid at the monitoring level C-C, the pick-up 33 is under a pressure equal to the pressure in the container B and the inlet end of the measuring duct 34 is not contacted by the liquid stream. . As the fluid appears at the monitoring level C-C ~ the liquid stream from the nozzle 2 mixes with the fluid downstream of the outlet section g of the shroud 3 and the liquid jet spreads out. At this point, the liquid flow occupies the entire outlet section 9 of the shroud 3, the inlet end of the measuring duct 3 is located within the liquid flow, and the pressure pickup 33
indicates changes in the hydrodynamic state of the liquid flow. The pilot version of the device disclosed above for monitoring liquid level has been tested in an extensive test program and a sufficiently high degree of confidence in its performance is obtained by the relatively simple construction of the device. I have proven that.

The devices disclosed herein enable reliable monitoring of fluid levels over a wide range of hydraulic values and have versatile capabilities that allow them to be used in most of a variety of industries and technical fields.

It should be understood by those skilled in the art that various modifications and changes can be made to the disclosed configuration of the device of the present invention without departing from the spirit and scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal sectional view of a device for monitoring the level of fluid in a container, which implements the present invention, at a time when the fluid has not reached the monitoring level; FIG. The same cross-sectional view as in Fig. 1 immediately after the instantaneous appearance of FIG. 5 is a schematic longitudinal sectional view of a monitoring device embodying the invention having a tube adapted to communicate with a container containing fluid at another monitoring level, the Figure 6 shows an upwardly projecting tube to bring the shroud into communication with the fluid present at the other monitoring level; FIG. 2 is a schematic longitudinal cross-sectional view of an apparatus embodying the invention having an inlet end of the tube positioned offset relative to the longitudinal axis of the shroud, showing that no fluid is present at both monitoring levels; FIG. 7 is a schematic longitudinal section of an apparatus embodying the invention having a fluid flow restrictor mounted in a downwardly projecting tube for passing the shroud through a container containing fluid at another monitoring level; Front view; Figure 8 is
a schematic longitudinal sectional view of a monitoring device for implementing the invention, with a pressure pick-up and an inlet section of said shroud and a suitable measuring duct, showing that fluid is present at another monitoring level; Figure 9 shows the measurement duct,
Fig. 8 is a schematic longitudinal cross-sectional view of an apparatus embodying the invention having a flow restrictor installed in the supply pipe;
The illustration shows a spiral rib inside the exit section of the shroud.
1 is a schematic longitudinal cross-sectional view of an apparatus embodying the invention showing that the fluid is present at the other monitoring level; FIG. 1 is a schematic longitudinal sectional view of an apparatus embodying the invention in which the inlet section of the measuring duct faces the outlet section of the shroud and extends coaxially with respect to the nozzle; Figure 12 shows an apparatus for carrying out the invention in which the inlet end of the measuring duct is located offset to the serpentine line of the nozzle which is arranged coaxially with respect to the outlet part of the shroud; This is a schematic vertical cross-sectional view of the system, showing that fluid is present at the other monitoring level.In the drawing, 1 is a "supply pipe," 2 is a "nozzle," 3 is a "shroud gourd," and 4a and 4b are "displays." Device” 5 is “Diaphragm”
6 is ``Open□'' 7 is ``Electric strain meter 8 is ``Inlet part katana 9 is ``Exit part 1Q', ``Neck part katana, Wing 1G''
2Q is a ``measuring duct'' and 23 is a ``liquid flow restrictor''. Melon 27 indicates "Rip Melon" 28 indicates "Shroud" 3 Bottles indicate "Outlet end" ○-0 indicates "Nozzle axis ratio D-D indicates "Monitoring level Melon C-C indicates "Monitoring level". Elder brother's enemy doctor 2 Choketsu 3 Chozaki 4 Parting holes dan 6 Anti-G7 Bonyaku Ihironephew 9 Brother's brother's brother or brother Zku

Claims (1)

Claims: 1. An apparatus for monitoring the level of a fluid in a container, the supply having a source of fluid under pressure greater than the pressure of the surrounding medium, a container containing the fluid, and an inlet end and an outlet end. a tube, the supply tube having an inlet end communicating with the liquid source and an outlet end of the supply tube adapted to direct the flow of fluid from the fluid source. a nozzle for discharging through an outlet area, and a shroud having an inlet portion and an outlet portion, the shroud having the inlet portion in communication with the nozzle and with the container containing fluid at a monitoring level. and the shroud has at least one cross-section, the ratio of the maximum dimension of the internal contour of the cross-section to the distance from the exit area of the nozzle to the cross-section being less than 0.35:1. the inlet portion of the shroud is configured such that the internal contour of its cross-section encloses therein the contour of the outlet area of the nozzle, and the inlet portion of the shroud further the level of the fluid in the container, characterized in that it has an indicator for displaying a change in the hydrodynamic state of the liquid stream exiting the nozzle caused by mixing the liquid stream with the liquid stream; Device to monitor. 2. The device according to claim 1, characterized in that the inlet portion of the shroud is provided with a tube having an inlet end communicating with a fluid at a monitoring level different from the monitoring level. device to do. 3. Apparatus according to claim 2, characterized in that the inlet end of the tube is spaced from the longitudinal axis of the shroud. 4. Device according to claim 2, characterized in that the tube is equipped with a device for restricting the flow of fluid. 5. The device of claim 1, wherein the display device comprises a pressure pickup having a pressure-responsive element and a measuring duct having an outlet end communicating with the pressure pickup, the inlet portion of the shroud comprising: A device characterized in that it communicates with the inlet end of the measuring duct of the display device. 6. Apparatus according to claim 5, characterized in that the inlet section of the shroud is in communication with the inlet end of the measuring duct via the supply tube and the nozzle. 7. The device according to claim 6, characterized in that it comprises a device for restricting the flow rate of the liquid provided in the supply pipe intermediate the liquid supply source and the inlet end of the measuring duct. 8. The device of claim 1, wherein the indicating device includes a pressure pick-up and a measuring duct having an outlet end communicating with the pressure pick-up, the inlet end of the measuring duct being in the outlet portion of the shroud. The shroud is disposed coaxially with the nozzle, facing the nozzle, and is provided with a helically extending rib on the inside of the outlet section of the shroud, which rib has a tangential velocity relative to the liquid stream exiting the nozzle. A device characterized in that it is adapted to apply a component. 9. The device of claim 1, wherein the display device comprises a pressure pickup having a responsive element and a measurement duct having an outlet end communicating with the pressure pickup, the inlet end of the measurement duct being connected to the pressure pickup. Apparatus arranged coaxially with the nozzle facing an outlet section of the shroud, the outlet section of the shroud extending at an angle to the longitudinal axis of the nozzle. 10. The device of claim 1, wherein the display device comprises a pressure pickup having a responsive element and a measurement duct with an outlet end communicating with the pressure pickup, the inlet end of the measurement duct being connected to the pressure pickup. Apparatus, wherein the apparatus is spaced from the axis of the nozzle facing an outlet section of the shroud, the outlet section of the shroud being disposed coaxially with the nozzle.