WO2015032619A1

WO2015032619A1 - Pressure transducer

Info

Publication number: WO2015032619A1
Application number: PCT/EP2014/067715
Authority: WO
Inventors: Gilbert Alexander Erdler; Dominik Herzog; Thomas Himmelsbach; Markus Pfeiffer; Erich Schwabenland
Original assignee: Siemens Aktiengesellschaft
Priority date: 2013-09-03
Filing date: 2014-08-20
Publication date: 2015-03-12
Also published as: DE102013217477A1

Abstract

The invention relates to a pressure transducer with a disc-shaped pressure sensor module (1) which has a pressure sensor (8) and a disc-shaped sensor carrier (10). A pressure feed duct (4) and a section (13) of an atmosphere-connecting duct (11, 12, 13, 14) run essentially parallel to one another in a pressure feed body (3). To reduce the manufacturing expenditure, the pressure sensor module (1) is prefabricated as a component which is already fitted with a pipe (12) for connecting the rear of the pressure sensor (8) to the section (13) of the atmosphere-connecting duct when said pressure sensor module (1) is welded into a pot-shaped recess (2) in the pressure feed body (3). The section (13) of the atmosphere-connecting duct is therefore already connected to the rear of the sensor by means of the pressure sensor module (1) and the subsequent mounting of a separate connecting hose is advantageously dispensed with. In addition, the mounting steps can then easily be automated, and the risk of assembly errors is reduced.

Description

description

The invention relates to a pressure transducer with a disk-shaped pressure sensor module, which has a pressure sensor on a disk-shaped sensor carrier, wherein the sensor carrier is firmly connected in the edge region with a pressure feed body, according to the preamble of claim 1.

From DE 42 44 459 Cl such a pressure transducer is already known. For a cost-effective production, a standard pressure sensor is provided there with a base and this is connected to the outer edge by welding with a Druckzu leadership body. To increase the mechanical stability of the pressure sensor module is located on an intermediate filling of resin with its back to the bottom of a cap-like component. The bottom of the cap-like component thus supports the base. The socket has lead wires in a spatial arrangement, as is common in so-called T08 sockets. From the base of the standard pressure sensor, a low-pressure side connection pipe for realizing a channel for connecting the sensor rear side with atmospheric pressure is led out, as well as a filling pipe, which serves to fill a pressure supply channel in the pressure supply body with a silicone oil. The opposite side of the pressure feed channel is closed by a separation membrane. An insulating tube with its one end is pushed onto the low-pressure side connection tube. The other end of the insulating tube is inserted into a substantially parallel to the pressure guide channel extending bore of the cap-like component, which leads via a lateral opening to the outside. A corresponding arrangement of a bore in the pressure feed body, in which also the other end of a

Hose for connecting the sensor back with the atmosphere surrounding the pressure transducer is arranged, DE 42 44 460 Cl. In the two known pressure transmitters is achieved by the respective arrangement of the channel for connecting the sensor back with the atmosphere surrounding the pressure transducer, which is an electronic circuit arrangement, which is located in a housing of the pressure transducer, in the event of pressure overload of the pressure sensor with accompanying mechanical breakthrough of the sensor membrane is protected from damage. For example, silicone can be used as tube material in standard pressure transmitters or in pressure transmitters with a pressure-resistant version of the transmitter housing polyether ether ketone (PEEK). A disadvantage of the known pressure transmitters in any case, the problematic handling of the hose during assembly and that the assembly is subject in particular in the pressure-resistant design with a certain risk of error. The tubing must be bent and glued or welded in place if it is not already preformed. On the one hand, unwanted mechanical stresses can occur in the bending process and the welding in the pressure sensor, on the other hand, these processes are associated with considerable effort during assembly. However, automating assembly operations to reduce manufacturing costs and scrap rates is difficult.

The invention is therefore based on the object to provide a pressure transducer whose production is associated with a lower effort.

To solve this problem, the new pressure transducer of the type mentioned in the characterizing part of claim 1 features. In the dependent claims, advantageous developments of the invention are described.

The invention has the advantage that, with particularly low assembly costs and high production reliability, protection of the electronic circuit arrangement in the housing of the pressure measuring Transformer can be achieved from damage caused by sensor breakage. In particular, the assembly of a tube made of silicone or PEEK is no longer required and the number of components is thus reduced. The reference pressure connection of the sensor rear side already takes place with the assembly of the pressure sensor module on the pressure feed body, so that it can be designated as a reference pressure connection integrated in the pressure sensor module. Such a pressure sensor module is mounted as a prefabricated component on the Druckzufüh- rungskörpers. This process is easier to automate and reduces the risk of assembly errors. Thus, the yield in the manufacturing process is improved and reduces the expense associated with the production. Manufacturing steps in assembly are required in smaller numbers and at the same time easier, faster and more reliable than previously feasible.

Another advantage is the fact that the same pressure sensor module can be used both in a standard measuring cell and in a flameproof version of the measuring cell. By thus achieved variant reduction reduces the number of component types to be kept and consequently also the production cost. With the elimination of the hose assembly also eliminates the previously required bonding processes for fastening the

Hose, which were associated with the risk of contamination of the pressure transmitter, such as silicone oil. Because of a possible silicone oil contamination especially in the pressure-resistant design of the pressure transmitter previously performed furnace and cleaning processes are no longer required in an advantageous manner.

By the invention, even pressure transmitters can be produced with comparatively low costs, in which, as in the pressure transducers known from DE 42 44 459 C1 or DE 42 44 460 C1, protection of the electronic circuitry of the pressure transducer against damage in the event of break-through Pressure sensor diaphragm is achieved in pressure overload, that a portion of the channel, which serves to connect the sensor back with the atmosphere surrounding the pressure transducer, substantially parallel to the pressure supply passage in the pressure-feeding body runs.

In a particularly advantageous embodiment of the invention, the pressure sensor module on a disk-shaped sensor carrier made of high-strength steel and it is for connecting the sensor back to the outlet opening of the portion of the

Atmosphärenverbindungskanals a tube provided, the two ends are each firmly connected to a pressure passage opening with the sensor carrier. Such a module can be completely prefabricated in a simple manner, so that after the welding of the pressure sensor module on the Druckzuführungskörper no further manufacturing steps for attaching the tube must be performed more. In addition, in this embodiment of the block advantageously no additional cap-like component for supporting the pressure sensor module is required, as was previously the case in the aforementioned DE 42 44 459 Cl. This leads advantageously to a further reduction of the manufacturing effort. An emergence of mechanical stresses in the pressure sensor due to the introduction of temperature in the production of the welded connection between the pressure feed body and the sensor carrier in its edge region can advantageously be almost completely excluded if capacitor discharge welding is used as the welding method. The energy of previously charged capacitors is transferred to the weld during the welding process. Advantages of this process are very high welding currents, the steep increase in current, the short welding time and thus the comparatively small heat affected zone due to the energy concentration

Weld area because short weld times minimize heat buildup in the environment. In addition, this method allows the secure welding of high-strength steels or Kovar alloys, which are advantageous as material for the disk-shaped sensor carrier can be used. This allows a smaller thickness of the sensor carrier and a shorter line feedthrough, which also reduces the manufacturing cost of the pressure transducer.

With reference to the drawings, in which an embodiment of the invention is shown, the invention and refinements and advantages are explained in more detail below. Show it:

1 shows a detail of a sectional view of a

2 shows a perspective view of the top side of a pressure transmitter

Pressure sensor module and

Figure 3 is a perspective view of the bottom of the

Pressure sensor module according to FIG. 2.

In the figures, like parts are given the same reference numerals.

As FIG. 1 shows, a pressure sensor module 1 is arranged in a pot-shaped recess 2 of a pressure feed body 3. The pressure feed body 3 has a pressure feed channel 4, which is widened in its upper part 5. In the upper part 5, a stopper 6, for example made of stealite is pressed, which can form a flame arresting safe route together with the channel 4 due to its properties and dimensions. The channel 4 is filled with a diaphragm seal, for example a silicone oil, through a filling tube 7, which was closed after the filling process. The one, lower side of a membrane of a pressure sensor 8 is surrounded by the pressure transmitter located in the channel 4, so that the pressure introduced from a process side via a separating membrane 9 is transmitted to the sensor 8. The upper side of the membrane of the pressure sensor 8 is designed as a low-pressure or reference pressure side via a disk-shaped sensor carrier. ger ger 10 attached opening 11, a pipe 12, a channel 13 and a side outlet opening 14 through connected to the atmosphere surrounding the pressure transducer. To avoid contamination, a filter 15 is arranged in the channel 13.

For example, above the pressure sensor module 1 is an electronic circuit arrangement for evaluating the signals of the pressure sensor 8 with the purpose of calculating a pressure value, which is used for example in a process engineering plant as a process variable for process control. Electronic circuitry and housing of the pressure transducer are of no significance to the understanding of the invention and therefore not shown in the drawings. They may, for example, be designed as described in the already mentioned DE 42 44 460 C1. The supply of the signals from the pressure sensor 8 to the electronic circuit arrangement takes place in a known manner via bonding wires, line bushings 16 and a multi-core ribbon cable 17, not shown. The arrangement of the cable bushings 16 corresponds to that of a conventional T08 socket, wherein one is replaced by the filling tube 7 ,

The sensor carrier 10 forms a low-tension mechanical base for the glued and / or soldered pressure sensor 8. The sensor carrier 10 is made of a high-strength steel or a Kovar alloy and can be made comparatively thin as a disk-shaped plate. Its stability is hardly affected by the pressure-tight cable bushings 16 for the electrical signals and by the filling and reference pressure ports. In the peripheral region, the sensor carrier 10 may be firmly connected to the bottom of the cup-shaped recess 2 of the pressure feed body 3 in a sealing and pressure-resistant manner, for example by laser or capacitor discharge welding. In this case, a capacitor discharge welding is preferably used, since this offers the advantages explained above for the pressure transducer. So that temperature fluctuations of the transmitter do not lead to additional mechanical stresses in the sensor carrier 10, this is Tube 12 is preferably made of a VACON alloy with a defined thermal expansion coefficient.

A pressure sensor module 1 shown in FIGS. 2 and 3 is provided as a prefabricated component during the assembly process, in which the tube 12 is already welded with its two ends before the pressure sensor module 1 is welded to the pressure feed body 3. As a result, no further assembly step is required for attaching a separate reference pressure hose and gluing the ends thereof, as was previously the case, so that the new pressure transmitter, as already explained in detail above, is associated with a significantly lower production cost. At the same time, since the channel for connecting the rear side of the pressure sensor 8 with the atmosphere surrounding the pressure transmitter points outwards past the electronic circuit arrangement, it is ensured that no process medium penetrates into the housing interior due to overload due to overload. Advantageously, the connection between the back of the pressure sensor 8 and the substantially parallel to the pressure supply channel 4 extending channel - section 13 is produced with the correct position welding of the pressure sensor module 1 in Druckzuführungskörper 3, since the pressure sensor module 1 with its disk surface a Outlet opening 18 of the extending in the pressure feed body 3 section 13 of the atmosphere communication channel, as shown in Figure 1.

The pressure sensor module 1, whose upper side is shown in FIG. 2 and its underside in FIG. 3, consists essentially of the sensor carrier 10, which is made of high-strength steel, seven pressure-tight electrical cable bushings 16, a pressure-tight feedthrough with the filling tube 7 and It is prefabricated as a component, so that the manufacturing steps during assembly significantly reduced and the risk of assembly errors due to an automated assembly are significantly reduced. Advantageously, the pressure sensor module 1 shown can be used in both a standard measuring cell and a pressure-resistant design, so that the number of variants is reduced, which also has a favorable effect on the production cost.

Claims

claims

1. Pressure transmitter with a disc-shaped pressure sensor module (1) having a pressure sensor (8) and a disc-shaped sensor carrier (10), wherein the sensor carrier (10) in the edge region with a pressure supply body (3) is firmly connected, wherein the Connection of the sensor back with the atmosphere surrounding the pressure transducer an atmosphere communication passage (11, 12, 13, 14) is provided, which extends at least with a portion (13) substantially parallel to a pressure supply channel (4) in the pressure feed body (3) in

that the disc-shaped pressure sensor module (1) covers with its disk surface an outlet opening (18) of the section (13) of the atmosphere connection channel extending in the pressure feed body (3) and

in that the sensor rear side is connected to the section (13) of the atmosphere connection channel by the pressure sensor module (1).

2. Pressure transmitter according to claim 1, characterized in that the disc-shaped sensor carrier (10) of the pressure sensor module (1) made of high-strength steel or an alloy, in particular Kovar, and that for connecting the sensor rear side with the outlet opening (18) of the Section (13) of the atmosphere communication passage a pipe (12) is provided, whose both ends are fixedly connected to the sensor carrier (10) in each case on a Druckdurchführungs- opening (11).

3. Pressure transmitter according to claim 1 or 2, characterized in that the disk-shaped pressure sensor module (1) by capacitor discharge welding with the Druckzuführungs- body (3) is firmly connected.