WO2007057433A1

WO2007057433A1 - Device and method for filling a pressure measuring pickup

Info

Publication number: WO2007057433A1
Application number: PCT/EP2006/068578
Authority: WO
Inventors: Langner Lutz
Original assignee: Endress+Hauser Gmbh+Co.Kg
Priority date: 2005-11-18
Filing date: 2006-11-16
Publication date: 2007-05-24
Also published as: DE102005055545A1; DE102005055545B4

Abstract

A method and a device are proposed for filling at least one cavity - which can be connected to a filling device via a first and second connection (21, 21a, 21b, 23, 23a, 23b) - of a pressure measuring pickup with a pressure-transmitting fluid (33) with which rapid filling can be carried out by virtue of the fact that each cavity is evacuated and each evacuated cavity is filled with fluid (33), in which method and device the fluid (33) is held in a reservoir device (31, 87) and the fluid (33) is transferred from the reservoir device (31, 87) via the first connection (21, 21a, 21b) into the respective cavity by means of a feed line (35) which can be closed with a feed line valve (V2), and fluid (33) is forced from a device (39) via the feed line (35) into the respective cavity by means of said device (39) which is connected to the feed line (35), upstream of the respective first connections (21, 21a, 21b).

Description

description

Device and method for filling a pressure measuring transducer

The invention relates to an apparatus and a method for filling a pressure measuring transducer with a pressure-transmitting liquid.

Pressure sensors are used in almost all industries for measuring

Press inserted. The measured pressure values are e.g. used to control, regulate and / or monitor an industrial manufacturing and / or processing process.

In pressure measurement technology, so-called semiconductor sensors, e.g. Silicon chips with doped resistive elements, used as pressure-sensitive elements. Usually, such a pressure sensor has a membrane-shaped pressure sensor chip, which is applied in a pressure measuring chamber on a base body. Pressure sensors are usually very sensitive and are therefore not directly exposed to a medium whose pressure is to be recorded. Instead, a filled with a liquid diaphragm seal is connected upstream. The pressure averager typically comprises a pressure receiving chamber, which is connected to the pressure measuring chamber via a pressure mediator line, which is closed to the outside by a separating membrane. In operation, the pressure to be measured is applied to the separation membrane and transferred via the liquid in the pressure measuring chamber. This applies both for the measurement of absolute pressures, as well as for the measurement of relative pressures and differential pressures. However, the invention is not limited to this particular form of pressure transducers, but may generally be used in conjunction with pressure transducers having at least one cavity which is filled with a pressure-transmitting liquid.

Fig. 1 shows an example of a pressure measuring transducer for measuring a pressure p, with a arranged in a pressure measuring chamber 1 pressure sensor 3 and a connected thereto via a pressure transmitter line 5 pressure transmitter 7 with an outwardly from a separation membrane 9 closed pressure receiving chamber 11th

Fig. 2 shows an example of a pressure transducer for measuring differential pressures. This comprises a sensor block 13, which has an interior which is subdivided by a measuring diaphragm 15 into a first and a second pressure measuring chamber 17, 19. To the pressure measuring chambers 17, 19 is respectively Connected via a pressure-medium line 5, a pressure transmitter 7 with an outwardly closed by a separation membrane 9 pressure receiving chamber 11.

The pressure measuring chambers 1, 17, 19, the pressure transmitter lines 5 and the

Pressure-receiving chambers 11 are filled with the pressure-transmitting liquid.

The filling of such pressure transducers is usually carried out by the evacuated to be filled cavities in the interior of the pressure transducer and the liquid flows by utilizing gravity from a container arranged above the cavities in the evacuated cavities.

In the German patent DE-Cl 197 44 208 a method for filling a pressure measuring transducer with a liquid is described. The pressure measuring transducer has a filling channel, into which a filler pin having a longitudinal channel over part of its overall length is introduced to such an extent that there is an open connection to the outside. The pressure transducer is evacuated and the pressurized fluid is introduced under the influence of gravity via the longitudinal channel and the filling channel. Subsequently, to produce a defined volume of liquid by inserting the Füllstifts over the end of the longitudinal channel also filled a supplemental amount of liquid.

In the German patent DD-A5 284 757 is another method for

Filling a pressure transducer with a liquid described in which the pressure transducer is first evacuated and filled with the liquid. Subsequently, a reservoir filled with the liquid is screwed onto the filling opening and the separating membrane is exposed to a negative pressure, by which it is sucked against a shape-same counter bearing. The anvil is designed so that a predetermined volume is enclosed under the separation membrane when the separation membrane rests against the abutment. In the suction process, this predetermined volume is drawn from the reservoir under the separation membrane. Then, while maintaining the negative pressure, the reservoir is unscrewed and the filling opening is closed in such a way that the interior of the pressure measuring transducer is not pressurized.

Conventional methods for filling pressure transducers with the pressure-transmitting liquid, in which the cavities are evacuated, and then filled under the action of gravity from a reservoir higher lying with the liquid can be very time-consuming under certain circumstances. The diaphragm seals of the diaphragm seals preferably have a very small diameter in order to minimize the volume of fluid required for filling hold. For example, capillary lines with a diameter of 1 mm are used. As a result, the time required for filling increases with the length of the lines. Depending on the geometry of the cavities and the length of the diaphragm seals, it may therefore take a long time for the cavities to fill with gravity under the action of gravity. For long cable lengths, for example with cable lengths of 10 m, economic filling with these methods is no longer feasible.

It is an object of the invention, a method and an apparatus for

Specify filling a pressure transducer, with or with the fast filling is feasible.

For this purpose, the invention consists in a device for filling at least one connectable via a first and a second connection to the device cavity in the interior of a pressure measuring transducer with a pressure-transmitting liquid, which comprises:

[0013] a device for generating a vacuum,

- Which can be closed by a first valve with a first

Connecting cable to the first port and a second

Connecting line to the second terminal of each cavity

Can be connected,

Which serves to evacuate each cavity,

[0019] a storage device in which the liquid is ready for filling,

- The closable via a supply line with a supply line with the

[0021] the respective first connection of the cavities is connected, and

Which serves to fill each evacuated cavity with liquid,

While the first valve is closed, and

[0024] - one of the respective first terminals upstream of the supply line

Connected device,

- which serves to press liquid via the feed line in each cavity,

While the first valve is closed.

According to a further development, the apparatus connected to the supply line has a compressible interior which can be filled with liquid in the uncompressed state and which presses a quantity of liquid contained therein into the supply line during compression of the interior space.

According to one embodiment, the first port of each cavity upstream device comprises a hydraulic cylinder, a bellows or one of a membrane sealed chamber.

According to one embodiment, the first port of each cavity is preceded by a sight glass.

According to a further embodiment, the second port of each cavity is followed by a sight glass.

According to one embodiment, the pressure transducer has at least one

Cavity, which comprises a pressure measuring chamber, a pressure receiving chamber and a pressure measuring chamber connecting the pressure measuring chamber with the pressure receiving chamber.

[0033] According to a development of the latter embodiment, the

Device comprises a receiving device for each pressure transmitter, in which a pressure receiving chamber to the outside final separation membrane can be arranged during filling in a pressure-tight recess, which is connected via an additional line to the device for generating the vacuum, and by means of this device can be evacuated.

[003Φ] According to a development, the storage device comprises a first and a second container, wherein

[0035] The first container as a reservoir for the filling of several

[0036] Pressure sensors are used

- The second container via a closable with a valve feed line

Is connected to the first container, and

[0039] the second container as a reservoir for the filling of a

[0040] Pressure measuring transducer serves.

Furthermore, the invention consists in a method for filling at least one connectable via a first and a second connection to a filling cavity in the interior of a pressure measuring transducer with a pressure-transmitting liquid, in which

[0042] every cavity is evacuated,

- Each evacuated cavity is filled with liquid, wherein

[0044] the liquid is provided by a storage device, and

[0045] the liquid can be closed by means of a supply valve

Supply line from the storage device via the

[0047] first connection is filled into the respective cavity,

[0048] the supply valve is closed, and

[0049] - with the inlet valve closed by means of a between the Inlet valve and the first connection to the supply line

Connected device fluid from the device over the

Feed line is pressed into the cavity.

Furthermore, the invention consists in a device for filling at least one connectable via a first and a second connection to the device

Cavity inside a pressure transducer with a pressure transmitting

Liquid comprising:

[0054] a device for generating a vacuum, which can be connected to the first connection via a first connecting line connectable with a first valve and to the second connection of each cavity via a second connecting line [0057] is

- which serves to evacuate the cavities, [0060] - a storage device in which the liquid for the filling [0061] is ready,

[0064] connected to the respective first port of the cavities via a supply line closable feed line [0063] - which serves to infuse each evacuated cavity with liquid to [0065] while the first valve is closed and [0066] - comprising means for urging at least a portion of the liquid contained in the reservoir means into each cavity via the inlet [0068] while the first valve is closed. Furthermore, the invention consists in a method for filling at least one cavity connectable via a first and a second connection to a filling device in the interior of a pressure measuring transducer with a pressure-transmitting liquid, in which [0071] - each cavity is evacuated,

[0072] - each evacuated cavity is filled with liquid, wherein [0073] - the liquid is provided in a storage device, and - at least part of the liquid contained in the storage device is pressed into each cavity via the supply line [0076] while the first valve is closed. The invention and further advantages will now be explained in more detail with reference to the figures of the drawing, in which three embodiments are shown; same elements are provided in the figures with the same reference numerals.

Fig. 1 shows a section through a pressure transducer;

Fig. 2 shows a section through a differential pressure transducer;

Fig. 3 shows a device for filling a cavity of a pressure measuring transducer;

Fig. 4 shows a bellows;

Fig. 5 shows a chamber sealed with a membrane;

Fig. 6 shows an apparatus for filling two cavities of a pressure transducer; and

Fig. 7 shows an apparatus for filling two cavities, in which a

Device with the liquid is pressed into the cavities, in

[0086] the storage device is integrated.

Fig. 3 shows an inventive device for filling at least one cavity in the interior of a pressure measuring transducer with a pressure-transmitting liquid.

In the illustrated embodiment, a pressure transducer with a single cavity to be filled is connected to the device. This is, for example, a pressure transducer, as shown in Fig. 1. The cavity comprises the pressure measuring chamber 1, the pressure mediator line 5 and connected to the pressure measuring chamber 1 via the pressure mediator line 5 pressure receiving chamber 11 of the pressure transmitter. The pressure receiving chamber 11 is closed to the outside through the separation membrane 9. The cavity can be connected to the device via a first and a second connection 21, 23. The first port 21 opens into the pressure measuring chamber 1. The second port 23 opens into the pressure receiving chamber 11. Preferably, the pressure transducer is arranged in the device such that the first port 21 is at the top and the second port 23 at the bottom with respect to the direction of gravity.

The device for filling the cavity comprises a device 25 for

Generation of a vacuum, for example a pump. This can be connected to the first port 21 via a first connecting line 27, which can be closed by a first valve V1, and to the second port 23 of the cavity via a second connecting line 29. The device 25 serves to evacuate the cavity.

In addition, the device for filling the cavity comprises a

Storage device 31, in which the liquid 33 is ready for filling. The liquid 33 is preferably an incompressible liquid with a low thermal expansion coefficient, eg a silicone oil.

The storage device 31 is connected via a connectable with a supply valve V2 supply line 35 to the first terminal 21 of the cavity. Both the supply line 35 and the first connection line 27 are connected to the first connection 21 of the cavity. For this purpose, a T-shaped connecting element 37 is provided in the illustrated embodiment, on the crossbar on one side of the first connecting line 27 and on the other side, the supply line 35 are connected. The trunk of the T-shaped connecting element 37 is connected to the first terminal 21 of the cavity. The storage device 31 serves to infest the previously evacuated cavity with liquid 33. In this case, the supply valve V2 is open and the first valve Vl is closed. The reservoir 31 is located above the cavity with respect to the direction of gravity. This has the effect that the liquid 33 automatically flows into the cavity when the supply valve V2 is open and the first valve V1 is closed due to gravity. This process is supported by a continuation of the evacuation of the cavity. The evacuation of the cavity takes place during filling exclusively via the second connection 23 and the second connection line 29.

According to the invention, the first connection 21 is preceded by a device 39, which is connected to the supply line 35, and liquid 33 is used to press into the cavity via the supply line 35, while the first valve V1 and the supply valve V2 are closed. In the illustrated embodiment, the device between the supply valve V2 and the first terminal 21 is connected to the supply line 35.

According to the invention, the procedure is such that the cavity is initially filled exclusively by utilizing gravity. In this form of filling, all easily accessible subspaces of the cavity fill very quickly with liquid 33. The easily accessible subspaces have large internal volumes and therefore absorb the largest proportion of the total volume required for filling. The largest proportion of the total volume penetrates very quickly into the cavity in this way. However, it would take a very long time to fill the remaining hard to reach subspaces of the cavity, esp. Long capillary lines with a small diameter, only by using gravity. The time required for this can be drastically shortened by the device 39 according to the invention. For this purpose, the largest share of required total volume filled by gravity into the cavity. Subsequently, the supply valve V2 is closed and exerted by means of the device 39 pressure on the located between the inlet valve V2 and the first port 21 in the supply line 35 liquid 33. By this pressure, the liquid 33 is pressed into a cavity. Under pressure, the liquid 33 now penetrates much faster into the remaining hard to reach subspaces of the cavity.

The device 39 preferably has a compressible interior space 41, which can be filled in the uncompressed state via the supply line 35 with liquid 33, and a quantity of liquid contained therein in a compression of the interior 41 into the supply line 35 into pressed. This interior 41 is connectable in the illustrated embodiment via the supply line 35, the T-shaped connecting element 37 and the first valve Vl to the first connecting line 27 of the device 25 for evacuation. This offers the advantage that the interior space 41 can be evacuated in advance together with the cavity. In this case, the supply valve V2 is closed and the first valve Vl opened. Subsequently, the first valve Vl is closed and the supply valve V2 is opened and the interior 41 of the device 39 is filled with the liquid 33 by utilizing gravity. At the same time, the cavity is simultaneously filled with the liquid 33 by utilizing gravity. This process is continued until the largest proportion of the required total amount has penetrated into the cavity. Subsequently, the supply valve V2 is closed and the interior 41 is compressed. The closure of the supply valve V2 causes the thereby displaced liquid volume is pressed exclusively into the cavity. It prevents liquid 33 from being pressed back into the supply device 31.

In the embodiment shown in FIG. 3, the device 39 has a hydraulic cylinder 43, the interior 41 of which is compressible by a piston 45 guided in the cylinder. The piston 45 is moved by means of a pneumatic cylinder 47, which is controlled via a solenoid valve V4.

Alternatively, the device 39 may be e.g. have a bellows or a sealed by a membrane chamber.

Fig. 4 shows a bellows 49 with an interior 51 which through a

Compression of the bellows 49 can be compressed in the direction indicated in Figure 4 by an arrow P direction. The interior 51 is to be connected via a connection 53 to the supply line 35. The compression of the bellows 49 can be done manually. Alternatively, but here also a stepper motor or a similar device can be used, via which the inner volume of the interior 51 is set. By an appropriate control of the stepping motor, this process can be automated.

FIG. 5 shows a chamber 57 which is closed off by a membrane 55. The chamber 57 has an interior space 59 whose internal volume is dependent on the deflection of the membrane 55. On the membrane 55, a plunger 61 is externally formed. The volume of the inner space 59 is maximum when the plunger 61 is pulled outward in the direction of the arrow Pl, and minimal when the plunger 61 is pushed inward in the direction of the arrow P2. The interior 59 is to be connected via a connection 63 to the supply line 35.

Again, the deflection of the diaphragm 55 can be manual or automatic, e.g. by a stepper motor.

Preferably, a sight glass 65 is connected upstream of the first port 21 of the cavity, and / or a sight glass 65 is connected downstream of the second port 23 of the cavity. The sight glasses 65 are line segments, which have a viewing window 67, through which an insight into the line segment is granted. The sight glasses 65 are used during and / or after filling to control the filling process and / or the absence of bubbles in the filling. The information obtainable via the sight glasses 65 can be used, for example, to control the filling process. An example of this is that the filling process can be ended when the sight glass 65 connected downstream of the second connection 23 fills with liquid 33.

In place of or in addition to the sight glasses 65, level gauges 68, e.g. continuously fill level in the line segment measuring level sensors or level limit switches are used, the output signal provides information about the current level in the respective line segment. The output signal can be supplied to a control device, for example, and used to automate the filling process. By means of this control device, the entire filling process can be automated by the control device controls both all existing valves and the device 39, including the level information.

For filling of pressure transducers, the pressure transmitter 7 having a closed by a separation membrane 9 pressure receiving chamber 11, which has Device preferably a receiving device 69 for each diaphragm seal 7, in which the separation membrane 9 is arranged during filling in a pressure-tight closed recess 71. The recess 71 is connected via an additional line 73 to the device 25 for generating the vacuum, and by means of this device 25 can be evacuated. This offers the advantage that acts on both sides of the separation membrane 9, the same pressure and the separation membrane 9 is when filling in its rest position.

During filling, liquid is removed from the reservoir 31. Accordingly, the degree of filling of the reservoir 31 changes and there is a cavity 75 in the reservoir 31 above the liquid 33, the internal volume of which depends on the degree of filling of the reservoir 31. Preferably, this cavity 75 is evacuated. This avoids that air or gas from the environment of the reservoir 31 can penetrate into the liquid 33 and can get into the cavity of the pressure measuring transducer with the liquid 33. In the embodiment shown in Fig. 3, the evacuation of the cavity 75 takes place in the reservoir 31 via the device 25. This is connected via a third connecting line 77 and a port 79 to the cavity 75. The port 79 is located on the reservoir 31 above the maximum degree of filling.

The invention comprises a method for filling at least one cavity, which can be connected to a filling device via a first and a second connection 21, 23, inside a pressure measuring transducer with a pressure-transmitting liquid 33. The method is described below with reference to FIG Filling device explained. The pressure transducer is, as shown in Fig. 3 used in the filling and connected. In a first method step, the cavity is evacuated. In this case, the first valve Vl is opened and the supply valve V2 is closed. The interior 41 of the device 43 is uncompressed and is also evacuated.

In a next step, the evacuated cavity is filled with liquid 33. Parallel to this and at the same time, the interior 41 of the device 39 is filled with liquid 33. This filling takes place by utilizing gravity, in that the liquid 33 is provided in a storage device 31 arranged above the cavity of the pressure measuring sensor and the interior 41 of the device 39, and via the supply line 35 closable with the supply valve V2 from the storage device 31 into the interior 41 and via the respective first port 21 in the respective cavity and inflows. In this case, the first valve Vl is closed and the supply valve V2 opened.

Alternatively, this part of the filling process can be divided into two parts, namely a first part, in which first only the device 39 is filled, and a second in that the cavity is then filled. For this purpose, an additional valve V in the feed line 35 is required that the device 39 is connected downstream. The valve V is opened during the evacuation and closed during the filling of the interior 41 of the device 39. Subsequently, the valve V is opened to fill the cavity.

In the next step, the supply valve V2 is closed, and pressed with the inlet valve V2 closed by means of the connected between the supply valve V2 and the first port 21 to the supply line 35 device 39 liquid 33 from the device 39 via the supply line 35 into the cavity. During this process, the first valve Vl remains closed. Due to the pressure exerted by this, the liquid 33 penetrates very quickly into the smallest subspaces of the cavity and in capillaries and the filling can be completed quickly.

Following the filling of the pressure transducer is suspended and its terminals 21, 23 are closed. Initially, the device 25 for generating the vacuum is separated from the connection lines 27, 29 and 73. This is done in the embodiment shown in FIG. 3 by a valve V5, via which the three connecting lines 27, 29, 73 are connected to the device 25. Subsequently, a connected to the connecting lines 27, 29, 73 part of the filling device is vented. This is done in the illustrated embodiment via a connection to the first, the second and the third connecting line 27, 29, 73 with a valve V6 sealable connection 81 with the environment. Valve V6 is closed during evacuation and during the entire filling process and is only opened for final ventilation. During ventilation, the first valve Vl is open and the supply valve V2 remains closed.

In a final operation, the terminals 21, 23 of the cavity of the

Pressure sensor sealed. This can be done for example by balls, which are pressed into corresponding recesses of the terminals 21, 23.

FIG. 6 shows a further exemplary embodiment of a device according to the invention

Contraption. Due to the great agreement with the previous embodiment, only the existing differences will be described below explained in more detail. One difference is that the device here is designed to fill two cavities of a pressure transducer. The pressure measuring transducer is, for example, a differential pressure transducer, as shown in FIG. 2.

The two cavities each comprise a pressure measuring chamber 17 and 19, respectively, and the pressure receiving chamber 11 of the pressure transmitter 7 connected therewith via the respective pressure transmitter line 5. The pressure receiving chambers 11 are each closed by means of a separating membrane 9.

Each cavity has a first terminal 21a, 21b and a second one

Terminal 23a, 23b, via which the cavities are connected to the device. The two first connections 21a, 21b are connected via the T-shaped connection 37 to the first connection line 27 and to the supply line 35. For this purpose, a fork 83 is provided, via which the trunk of the T-shaped connecting piece 37 is connected to the two first connections 21a, 21b. Analogously, the two second terminals 23a, 23b are connected via a further fork 85 to the second connecting line 29.

In the same way, of course, in parallel more cavities to the

Can be connected device in which instead of the bifurcation with a correspondingly higher number of branches are used.

Another difference is that in the embodiment shown in Fig. 6, a storage device 87 is used, which comprises a first container 89 and a second container 91.

The first container 89 serves as a reservoir for the filling of several

Pressure measuring transducers. Above the liquid 33, the first container 89 has a cavity 93, the internal volume of which depends on the degree of filling of the container 89. This cavity 93 is evacuated via the device 25 just like the cavity 75 of the reservoir 31. The device 25 for evacuation is connected via the third connecting line 77 above the maximum filling level of the container 89 to the cavity 93.

The second container 91 is closed by a valve V7

Supply line 95 is connected to the first container 93. The second container 91 serves as a reservoir for the filling of a pressure measuring transducer. The second container 91 is filled via the feed line 95 and in turn feeds the supply line 35, which can be closed with the valve V2, via which the pressure measuring transducer and the device 39 are then filled. The feed line 95 is connected via a closable by means of a valve V8 fourth connecting line 97 to the device 25 for generating the vacuum. The fourth connecting line 97 opens into the feed line 95 between the valve V7 and the second container 91.

The filling according to the invention takes place here essentially analogously to the method previously described with reference to the device of FIG. 3. At the beginning, only the first container 89 is filled with liquid 33 and the valve V7 is closed. The pressure transducer is connected to the device by connecting the two cavities via their first connections 21a, 21b and their second connections 23a, 23b. In a first process step is evacuated. The valves V1, V2, V5, V8 and V are opened, and the valves V6 and V7 are closed. As a result, the cavities in the pressure measuring transducer, the second container 91, the feed lines 95, the supply line 35, and the first, the second, the third and the fourth connecting line 27, 29, 73 and 97 are evacuated. The interior 41 of the device 39 is uncompressed and is also evacuated.

Subsequently, the second container 91 and the device 39 are filled with liquid 33. For this purpose, valves V8 and V are closed and then valve V7 is opened. During this phase, therefore, the valves V2, V5 and V7 are open and the valves V, V6 and V8 are closed.

In a next step, the evacuated cavities of the

Pressure sensor filled with liquid 33. For this purpose, the valves Vl and V7 are first closed and then the valve V is opened. In this phase, consequently, the valves V, V2 and V5 are opened and the valves Vl, V6, V7 and V8 are closed. This filling takes place using gravity.

Subsequently, the filling is continued by means of the device 39. For this purpose, the supply valve V2 is closed, and pressed with the inlet valve V2 closed by means of the connected between the inlet valve V2 and the first port 21 to the supply line 35 device 39 liquid 33 from the device 39 via the supply line 35 into the cavity. During this process, the first valve Vl remains closed. Due to the pressure exerted by this, the liquid 33 penetrates very quickly into the smallest subspaces of the cavity and in capillaries and the filling can be completed quickly. The process is completed when the visible through the sight glasses 65 liquid 33 is free of bubbles.

After filling, the pressure transducer is suspended and its connections 21, 23 are closed. Initially, the device 25 for generating the vacuum from the connecting lines 27, 29 and 73 is separated by the closure of the valve V5. Subsequently, a connected to the connecting lines 27, 29, 73 part of the filling device is vented by opening the valve V6. Valve V6 is closed during evacuation and during the entire filling process and is only opened for final ventilation. During ventilation, the first valve Vl is opened and the supply valves V2 and V7 remain closed.

In a final operation, the terminals 21, 23 of the cavity of the

Pressure sensor sealed. This can be done for example by balls, which are pressed into corresponding recesses of the terminals 21a, 21b, 23a, 23b.

In the exemplary embodiments described, the storage device 31 or 87 is always completely separate from the device 39, via which liquid 33 is pressed into the cavities. However, it is also possible to integrate the device 39 in the storage device. In that case, it is possible to carry out the entire filling process under the action of pressure on the liquid 33. Fig. 7 shows a possible embodiment for this purpose. Since the filling device shown there is largely identical to the device shown in FIG. 6, only the existing differences will be explained in more detail below. The only difference is that the storage device 99 shown here comprises a device 101, which serves to press at least a portion of the liquid 33 contained in the storage device 99 via the supply line 35 into each cavity, while the first valve Vl is closed , For this purpose, instead of the second container 91 shown in FIG. 6, a container 103 with a compressible inner space 105 was used. The container 103 is filled as well as the container 91 via the feed line 95. Subsequently, an additional valve V9 provided directly on the container 103 is closed. This prevents liquid 33 from being forced back into the feed line 95. Subsequently, the entire filling process can be carried out by exerting pressure on the liquid 33 under pressure. The filling takes place analogously to the filling operations described above, wherein at least a portion of the liquid 33 contained in the storage device 99 is pressed via the supply line 35 into each cavity, while the first valve Vl is closed.

In the illustrated device, this part is that part in the container 103 contained amount of liquid, which is displaced by a compression of the inner space 105. As a result, the liquid 33 is pressurized and pressed into the respective cavities. For this purpose, the device 101 comprises, for example, a piston 107 which is guided in the container 103 and, like the piston 45 of the hydraulic cylinder, serves to compress the interior 105 of the container 103. The piston 107 is moved, for example, via a pneumatic cylinder, not shown in FIG. 7, or a stepping motor. The device illustrated in FIG. 7 can additionally have the one already described

Device 39 included. But it can also be dispensed with appropriate dimensioning of the device 101 to the device 39.

[0128]

Table 1

Claims

claims

1. An apparatus for filling at least one via a first and a second port (21, 21 a, 21 b, 23, 23 a, 23 b) connectable to the device cavity in the interior of a pressure measuring transducer with a pressure-transmitting liquid (33), which comprises - a device (25) for generating a vacuum, - the one via a first valve (Vl) closable first connecting line (27) to the first terminal (21, 21a, 21b) and via a second connecting line (29) to the second port (23, 23a, 23b) of each cavity is connectable, - which serves to evacuate the cavities, - a storage device (31, 87), in which the liquid (33) is ready for filling, - via a with a supply line (V2) closable supply line (35) is connected to the respective first port (21, 21a, 21b) of the cavities, - which serves to fill each evacuated cavity with liquid (33), while the first Venti l (Vl) is closed, and - one of the respective first terminals (21, 21a, 21b) upstream, connected to the supply line (35) device (39), - which serves liquid (33) via the supply line (35) in Pressing each cavity while the first valve (Vl) is closed.

2. Device according to claim 1, wherein the to the supply line (35) connected device (39) has a compressible interior space (41) which can be filled in the uncompressed state with liquid (35), and an amount of liquid therein a compression of the interior (41) into the supply line (35) pressed into it.

3. Device according to claim 1, wherein the first terminal (21, 21a,

21b) of each cavity upstream device (39) comprises a hydraulic cylinder (43), a bellows (49) or from a membrane (55) closed chamber (57).

4. Apparatus according to claim 1, wherein the first port (21, 21 a, 21 b) of each cavity, a sight glass (65) is connected upstream.

5. Apparatus according to claim 1, wherein the second port (23, 23 a, 23 b) of each cavity, a sight glass (65) is connected downstream.

6. The apparatus of claim 1, wherein the pressure transducer has at least one cavity having a pressure measuring chamber (1, 17, 19), a pressure receiving chamber (11) and a pressure measuring chamber (1, 17, 19) with the Pressure receiving chamber (11) connecting the pressure transmitter line (5).

7. Apparatus according to claim 6, wherein the device is a

Receiving device (69) for each pressure transmitter (7), in which a pressure receiving chamber (11) outwardly terminating separation membrane (9) in which the separation membrane (9) during filling in a pressure-tight closed recess (71) can be arranged over an additional line (73) is connected to the device (25) for generating the vacuum, and by means of this device (25) is evacuated.

8. The apparatus of claim 1, wherein the storage device (87) comprises a first and a second container (89, 91), wherein - the first container (89) serves as a reservoir for the filling of a plurality of pressure transducers, - second container (91) via a with a valve (V7) closable feed line (95) to the first container (89) is connected, and - the second container (91) serves as a reservoir for the filling of a pressure measuring sensor.

9. A method for filling at least one of a first and a second

Connection (21, 21a, 21b, 23, 23a, 23b) to a filling device connectable cavity in the interior of a pressure transducer with a pressure transmitting liquid (33), in which - each cavity is evacuated - filled each evacuated cavity with liquid (33) is, wherein - the liquid (33) in a storage means (31, 87) is provided, and - the liquid (33) via a supply line with a valve (V2) closable feed line (35) from the storage means (31, 87) via the the first connection (21, 21a, 21b) is filled into the respective cavity, - the supply valve (V2) is closed, and - with the supply valve (V2) closed by means of a supply line between the valve (V2) and the respective first port (21, 21a , 21b) to the supply line (35) connected device (39) liquid (33) from the device (33) via the feed line (35) is pressed into the respective cavity.

10. Device for filling at least one via a first and a second port (21, 21 a, 21 b, 23, 23 a, 23 b) connectable to the device cavity in the interior of a pressure measuring transducer with a pressure-transmitting liquid (33), which comprises in that a device (25) for generating a vacuum is connected to the first connection (21, 21a, 21) via a first connecting line (27) which can be closed by a first valve (Vl) 21b) and via a second connecting line (29) to the second port (23, 23a, 23b) of each cavity is connectable, - which serves to evacuate the cavities, - a storage device (99), in which the liquid (33) is ready for the filling, - which is connected via a supply line (35) closable with a supply valve (V2) to the respective first connection (21, 21a, 21b) of the cavities, - which serves to supply each evacuated cavity with liquid (33 ), while the first valve (Vl) is closed, and - which comprises a device (101) serving to supply at least part of the liquid (33) contained in the storage device (99) via the supply line (35) Pressing each cavity while the first valve (Vl) is closed. 11. Method for filling at least one cavity which can be connected to a filling device via a first and a second connection (21, 21a, 21b, 23, 23a, 23b) in the interior of a pressure measuring transducer with a pressure-transmitting liquid (33) in which each cavity is evacuated - Each evacuated cavity is filled with liquid (33), wherein - the liquid (33) is provided in a storage device (99), and - at least a part of the liquid contained in the storage device (99) (33) via the supply line (35) is pressed into each cavity while the first valve (Vl) is closed.