Pressure measuring unit for measuring pressure

Abstract

A pressure measuring cell for measuring pressure, having: - a pressure measuring cell (500); - a rotationally symmetrical sensor cannula (400), into which the pressure measuring cell (500) is inserted; - a rotationally symmetrical process connection (300), wherein one end (370) of the process connection (300) has an inwardly extending, encircling stop surface (310) intended for the sensor cannula, and the other end (380) of the process connection (300) has an opening (330) for receiving the sensor cannula; - a ring-like process seal (600), which continues in an annular, radial ring and exerts a sealing action in a sealing plane between the sensor cannula (400) and the stop surface (310) of the process connection (300), in order thus to prevent process medium from entering into the pressure measuring cell (100); - wherein the stop surface (310) of the process connection (300) and / or a counter stop surface (432) of the sensor cannula (400), which in the installed state is oriented towards the stop surface, have a plurality of individually formed web plates (435), which are configured in a manner dependent on the characteristics of the process seal such that the process seal cannot be pressed into the opening.

Description

TECHNICAL FIELD

[0001] The present invention relates to a pressure measuring unit for measuring a pressure. BACKGROUND

[0002] In automation technology, pressure measuring units are often used to monitor a process medium. Such a pressure measuring unit is usually composed of a process connector for fixing the pressure measuring unit in a measuring point of an automation plant. A pressure measuring cell is inserted into the process connector so that the front is flush, i.e. faces the process, and is sealed from the process by a process seal, so that the process medium cannot escape or enter the housing of the pressure measuring unit.

[0003] In hygienic applications, i.e. processes requiring a high degree of cleanliness, for example in the food industry, pharmaceutical or biochemistry, the relevant certification authorities, for example 3-A or the European Hygienic Engineering and Design Group (hereinafter referred to as EHEDG), specify the identification of a leaking process seal.

[0004] One way of detecting such a leaking process seal is to use electronic means, for example a sensor in the form of an electronic nose, which detects the entry of the process medium into the housing of the pressure measuring unit. Such a method is described, for example, in EP 102 55 279 A1.

[0005] The disadvantage of this is that, on the one hand, the sensor has to be integrated into the pressure measuring unit and, in addition, a corresponding electronic unit for controlling the sensor is required. SUMMARY

[0006] It is therefore an object of the present invention to propose a simpler method of monitoring a process seal for leaks.

[0007] According to the invention, this object is achieved by a pressure measuring unit according to claim 1.

[0008] The pressure measuring unit for measuring a pressure according to the invention comprises:

[0009] - a pressure measuring cell;

[0010] - a rotationally symmetrical sensor sleeve into which the pressure measuring cell is inserted;

[0011] - a rotationally symmetrical process connector for releasable fastening of the pressure measuring cell to a wall of a measuring point, wherein one end of the process connector has an inwardly extending circumferential stop surface intended for the sensor cannula, and the other end of the process connector has an opening for receiving the sensor cannula, wherein, in the installed state, the sensor cannula together with the pressure measuring cell is inserted through the opening into the process connector up to the stop surface, so that the pressure measuring cell is introduced into the measuring point with the front substantially flush;

[0012] - a ring-shaped process seal which radially surrounds and seals in the sealing plane between the sensor cannula and the stop surface of the process connector in a ring shape in order to prevent the process medium from entering the pressure measuring cell;

[0013] - wherein the stop surface of the process connector and / or the counter stop surface of the sensor cannula, which is oriented towards the stop surface in the installed state, has several individually formed webs which are formed in such a way that, in the installed state, several openings are formed between the counter stop surface of the sensor cannula and the stop surface of the process connector, which have a defined height and width defined by the configuration of the webs, wherein the several openings together form a fluid path network consisting of several individual fluid paths which continue parallel to one another, via which, in the event of failure of the process seal, the process medium is guided from the sealing plane of the process seal to at least one opening which is visible from the outside in the installed state of the pressure measuring cell, wherein the webs are designed in such a way that the sum of the individual cross sections of the several openings corresponds to a predefined minimum cross section, wherein the defined height and the defined width are used to calculate the individual cross sections, and wherein, depending on the properties of the process seal, the webs are designed in such a way that the process seal does not extrude into the openings.

[0014] A pressure measuring cell is proposed in which a leak in the process seal can be detected because the process medium is guided from the location of the leak (in the sealing plane of the process seal between sensor cannula and process connector) via an internal fluid path network to a leak opening, which can be easily identified by an operator / service technician. The leak in the process seal signals itself by the escape of process medium from the leak opening. According to the invention, the fluid path network comprises not only a single path through which the process medium is guided, but also a plurality of individual paths which extend parallel to one another, via which the process medium is guided from the leaking process seal to the leak opening.

[0015] In order to prevent damage to the seal, for example due to the seal being pressed into the openings formed by the webbing, according to the application it is proposed that the webbing is designed in such a way that a plurality of openings are formed into which the seal can no longer be pressed or at least can be pressed to a lesser extent. The webbing is designed in such a way that the sum of the individual cross sections of each opening results in a total cross section which corresponds to or is not less than a predefined minimum cross section. The minimum cross section can be predefined in particular by standards, in particular the European Hygienic Engineering and Design Group and / or the 3-A sanitary standards. With regard to the width of the openings, the minimum width of each opening will be used to determine the overall cross section of the openings, i.e. the width of the openings adjacent to or against which the process seal rests.

[0016] An advantageous embodiment of the pressure measurement unit provides that the webbing is designed in such a way that the defined height does not exceed the gap size predefined for the process seal. This means that the webbing is designed in such a way that the defined height of the openings is significantly smaller than the diameter of the process seal, i.e. at least 15 times, preferably at least 20 times and particularly very preferably at least 25 times smaller than the diameter of the process seal.

[0017] A further advantageous embodiment of the pressure measurement unit provides that the webbing is formed in such a way that the defined height is less than 0.20 mm, preferably less than 0.15 mm, particularly preferably less than 0.10 mm and most preferably approximately 0.08 mm.

[0018] A further advantageous embodiment of the pressure measurement unit provides that the webbing is arranged radially rearward of the process seal in such a way that the edge of the webbing which is oriented towards the process seal does not come into contact with the process seal which has not yet been pressed in the installed state. Since the webbing is arranged rearward relative to the process seal, the webbing is located in a region in which the seal does not normally press.

[0019] A further advantageous embodiment of the pressure measurement unit provides that the outer side surface of the sensor sleeve in the region of the lower portion which, in the installed state, adjoins the inner side surface of the process connector and / or the inner side surface of the process connector in the region of the lower portion which, in the installed state, adjoins the outer side surface of the lower portion region of the sensor sleeve or said outer side surface has a number of vertical recesses, wherein the number of vertical recesses is formed in such a way that the sum of the individual cross sections of the number of vertical recesses corresponds to a predefined minimum cross section. In particular, this embodiment can provide that the sensor sleeve in the lower portion and / or the process connector in the lower portion has at least one circumferential collection groove for collecting the process medium supplied via the number of openings, wherein the at least one collection groove is formed in such a way that the cross section of the collection groove corresponds to the predefined minimum cross section.

[0020] A further advantageous embodiment of the pressure measurement unit provides that the sensor spool has a circumferential shoulder ring, in the installed state the sensor spool is inserted into the opening of the process connector up to said circumferential shoulder ring, and wherein the sensor spool has a further circumferential collection groove, preferably directly adjacent to the shoulder ring, said further groove is designed to guide the process medium to said at least one externally visible leakage opening, wherein said further collection groove is designed such that the cross section of said further collection groove corresponds to the pre-specified minimum cross section. In particular, this embodiment can provide that the lower part of the sensor spool and / or the lower part of the process connector has at least one circumferential collection groove for collecting the process medium supplied via said several openings, wherein said at least one collection groove is formed such that the cross section of said collection groove corresponds to said pre-specified minimum cross section.

[0021] A further advantageous embodiment of the pressure measurement unit provides that the sensor spool has a circumferential shoulder ring, in the installed state the sensor spool is inserted into the opening of the process connector up to said circumferential shoulder ring, and wherein the sensor spool has a further circumferential collection groove, preferably directly adjacent to the shoulder ring, said further circumferential collection groove is designed to guide the process medium to said at least one externally visible leakage opening (340), wherein said further collection groove is designed such that the cross section of said further collection groove corresponds to the pre-specified minimum cross section.

[0022] A further advantageous embodiment of the pressure measurement unit provides that the at least one externally visible leakage opening is formed such that the cross section or the sum of cross sections corresponds to the pre-specified minimum cross section.

[0023] A further advantageous embodiment of the pressure measurement unit provides that the at least one externally visible leakage opening is formed on the rear side of the process connector, in the installed state the shoulder ring of the sensor spool is fixed on said rear side.

[0024] A further advantageous embodiment of the pressure measurement unit provides that the pre-specified minimum cross section corresponds to a standard pre-specification, in particular a hygienically relevant standard pre-specification of the European Hygienic Engineering Design Group and / or 3-A, in particular the pre-specification of the standard 74-07 of 3-A published in March 2019. In particular, this embodiment can provide that the pre-specified minimum cross section has at least 4.0 square millimeters (mm 2 ), preferably at least 4.5 mm 2 , and particularly preferably at least 4.9 mm 2 . BRIEF DESCRIPTION OF DRAWINGS

[0025] The application is explained in more detail on the basis of the following figures. The following are shown:

[0026] Figure 1 : cross section through the pressure measuring cell,

[0027] Figure 2 : detailed view of a region of the pressure measuring cell, in which region the sealing of the pressure measuring cell with respect to the process medium takes place by means of the process seal,

[0028] Figure 3 : exploded view of the sensor sleeve, the process seal and the process connector via which the pressure measuring cell is attached at the measuring point,

[0029] Figure 4 : perspective view of a first embodiment of the sensor sleeve,

[0030] Figure 5 : perspective view of a second embodiment of the sensor sleeve, and

[0031] Figure 6 : perspective view of an embodiment of the process connector. DETAILED DESCRIPTION

[0032] Figure 1 A partial cross section through the pressure measuring cell 100 is shown. Figure 1 The pressure measuring cell 100 shown comprises several main elements: a rotationally symmetrical sensor sleeve 400; a pressure measuring cell 500 which is inserted into the sensor sleeve 400 flush with the front; a likewise rotationally symmetrical process connector 300 for fastening the pressure measuring cell 1 to the wall of a vessel or pipe containing a process medium; a process seal 600 which is inserted at the front with respect to the process for sealing the pressure measuring cell 500; and a housing 200 which is fastened via a housing adapter 210.

[0033] The rotationally symmetrical sensor sleeve 400 has a substantially hollow cylinder which has an outer peripheral shoulder ring 420, a lower portion 430 which is adjacent to the shoulder ring 420 and which can be inserted into the process connector 300, and an upper portion 410 which is adjacent to the shoulder ring 420. The lower portion 430 of the sensor sleeve 400 is designed in such a way that the sensor sleeve can be inserted with the aid of the lower portion 430 into a corresponding opening 33 of the process connector 300. The shoulder ring 420 has several, preferably concentric, holes 421 through which the housing 202 can be connected to the process connector 300 by means of screws 220. The end of the sensor sleeve 400 which is opposite the housing also has an inwardly extending radial circumferential stop surface 433. The pressure sensing element 500 is inserted into the sensor sleeve 400 flush with the front with the aid of the stop surface 433 and can be positioned with the aid of an additional rotationally symmetrical centring ring 700.

[0034] The centering ring 700 has a substantially rotationally symmetrical L-shaped cross section with a short leg 710 and a long leg 720. The stop surface 433 and the centering ring 700 match each other such that the centering ring 700 abuts against the stop surface 433 by means of the short leg 710. Furthermore, the centering ring 700 is designed such that the long leg 720 surrounds the outside of the pressure measurement cell 500 so as to be substantially flush, such that the pressure measurement cell 500 is centrally aligned in the sensor cannula 400.

[0035] The pressure measurement cell 500 used is preferably a ceramic pressure measurement cell, which has a preferably ceramic base body 510 and a pressure-sensitive, preferably ceramic measurement diaphragm 520, which is moved out of its abutment position depending on the pressure acting thereon. The measurement diaphragm 520 and the base body 510 are joined to each other in a pressure-tight manner at their edges by means of a joint 530, thereby forming a measurement chamber.

[0036] In order to acquire the pressure-dependent displacement and in order to convert the pressure-dependent displacement into an electrical signal, the pressure measurement cell 500 comprises one or more transducer elements. All transducer elements known from the prior art can be considered as transducer elements. However, the transducer elements are preferably capacitive transducer elements. A capacitive transducer element typically has at least one electrode, which is arranged on the inner side of the measurement diaphragm, and at least one counter electrode, which is arranged on the outer side of the base body opposite the inner side and faces the measurement diaphragm.

[0037] In turn, the process-facing end (front side) 370 of the rotationally symmetrical process connector 300, which has an inwardly extending radial circumferential stop surface 310 in the installed state, has the sensor cannula 400 together with the pressure measurement cell 500 inserted into the process connector 300 up to said surface. Here, the pressure measurement cell 500 is introduced into the sensor cannula 400 such that in the installed state the pressure-sensitive measurement diaphragm 520 is directed towards the process (front flush).

[0038] As Figure 2 As shown in Fig. 6, a radial circumferential process seal 600 is introduced between the pressure measurement cell 500 and the process connector 300 in order to prevent the penetration of process medium between the process connector and the sensor cannula. The process seal 600 can be designed, for example, in the form of an O-ring and consists of a material resistant to the process medium. For example, the process seal can comprise ethylene propylene diene rubber (EPDM), fluoroelastomer (FKM), perfluoroelastomer (FFKM), nitrile rubber (NBR) or fluoro-nitrile rubber. Such seals, in particular in the form of an O-ring, have specific properties related to the sealing behavior. Examples of such properties are the diameter or cord diameter or the Shore hardness of the seal.

[0039] To prevent the process seal 600 from slipping, the stop surface 310 of the process connector can be realized such that the stop surface 310 extends further inwards beyond the stop surface of the sensor sleeve 433 for the centering ring and has a geometry 320 in this area for receiving the process seal 600. Furthermore, to reduce the creep of the process seal, a nose 434 can be provided on the inner end of the stop surface of the sensor sleeve.

[0040] To be able to identify a failure of the process seal 600, the counter stop surface 432 of the sensor sleeve 400, which is oriented towards the stop surface in the installed state, has several individually formed web plates 435. The web plates 435 are designed such that, in the installed state, several openings 800 are created between the counter stop surface 432 of the sensor sleeve 400 and the stop surface 310 of the process connector 300. These openings 800 have a height H and a width B defined by the web plates. In the installed state, the process seal 600 is located in the area of the openings 800. Figure 4 and Figure 5 In the embodiment shown, the sensor sleeve has four radially outwardly extending web plates on each end face, which in the installed state results in four openings 800 via which the process medium is guided in the event of a failure of the process seal 600. Figure 4 and Figure 5 An example of an opening 800 formed by a web plate in the installed state is shown.

[0041] Depending on the specific properties of the process seal 600, the web plates 435 are formed such that the process seal 600 is difficult to press into the openings. This can be achieved in particular by the defined web plate height H not exceeding a gap size specified in advance for the process seal used in the installed state. Said gap size is usually specified in advance by the manufacturer of the process seal and is in particular dependent on the pressure exerted on the process seal, the diameter or string diameter of the process seal, the temperature of the medium at the process seal and the Shore hardness of the material of the process seal.

[0042] For example, for process pressures of < 3.5 MPa, the gap size for the process seal, in particular for a process seal formed from an elastomer material having a Shore A hardness of 70, can be less than 0.20 mm, preferably less than 0.15 mm, particularly preferably less than 0.10 mm and most preferably approximately 0.08 mm, such that the defined height of the web plate is realized accordingly.

[0043] To avoid damaging the process seal, the web plates can also be designed such that the edge of the web plate oriented towards the process seal is set radially back as seen from the process seal, so that the edge of the web plate oriented towards the process seal is not in contact with the process seal, which has not yet been pressed, in the installed state.Figure 5 The illustrated embodiment shows a webbing plate arranged in this way to the rear. By way of example, a recessed edge is indicated on one webbing plate by reference 437. Additionally or alternatively, in order to avoid damage to the process seal, the edge of the sensor sleeve which, in the installed state, is oriented towards the stop surface of the sensor sleeve which faces the process seal and the process connector can be rounded or chamfered. By way of example, in Figure 2 , the edge is denoted by reference symbol 390.

[0044] In addition to or as an alternative to the webbing plate 435 formed on the counter stop surface 432 of the sensor sleeve 400, a corresponding webbing plate can also be formed on the stop surface 310 of the process connector 300.

[0045] In the event of a process seal failure in the sealing plane between the process connector 300 and the sensor sleeve 400, process medium is guided through the opening 800 to the outside surface 431 of the lower portion of the sensor sleeve 400. The lower portion 431 of the sensor sleeve 400 can have a circumferential lower collection groove 438 which adjoins the end face, in which the supplied process medium is collected.

[0046] In order to guide the process medium from the lower collection groove 438 further to the externally clearly visible leakage opening 340, the outside surface 431 of the lower portion of the sensor sleeve can have several vertical recesses 436, as shown in Figure 3 . Furthermore, the lower portion of the sensor sleeve 400 can have an upper collection groove 439 which directly adjoins the shoulder ring 420, to which the vertical recesses 436 open. The vertical recesses 436 are thus formed such that, in the installed state, a fluid connection is created between the lower collection groove 438 and the upper collection groove 439, via which the process medium from the opening 800 is guided.

[0047] As an alternative or in addition to the vertical recesses 436 integrated into the outside surface 431 of the lower portion 430 of the sensor sleeve, the inside surface 380 of the process connector 300, which in the installed state adjoins the outside surface 431 of the lower portion 430 of the sensor sleeve 400, can comprise several vertical recesses 350. This can be useful, for example, if the design of the sensor sleeve means that it does not have enough material in the wall region to enable corresponding vertical recesses.

[0048] The vertical recesses 350, 436 can be introduced into the respective position, for example, by milling. Furthermore, these recesses can also be designed in the form of, for example, slots.

[0049] As a result of the openings, in combination with the vertical recesses 435, 350, 436 and / or the one or more collection grooves 438, 439, an internal fluid path network consisting of several individual fluid paths is formed via which process medium penetrating due to a defective process seal 600 is guided from the sealing plane in which the process seal 600 forms a pressure-tight connection between the stop surface of the process connector and the sensor sleeve (which is fixed on the stop surface by its end face) to the externally clearly visible leakage opening 340. As shown in Figure 5 Fig. 6, the leakage opening 340 can be formed on a rear side 360 of the process connector which faces away from the front side. Furthermore, instead of a single leakage opening 340, several leakage openings can also be provided.

[0050] In order to illustrate the individual fluid paths EP1-EP4, as an example, in Figure 4 and Figure 5 four individual paths are shown with dashed arrows, respectively. Thus, each individual path comprises the opening 800 which opens into the lower collection groove 438 which adjoins the end face of the sensor sleeve 400, the vertical recess 436 which opens into the lower collection groove 438 and the upper collection groove 439 which adjoins the shoulder ring, and the upper collection groove 439 which adjoins the shoulder ring.

[0051] The opening 800 or the vertical recess is designed such that the sum of the individual cross sections A opening_n or the individual cross sections A recess_n of the several openings 800 along the fluid path corresponds to a pre-specified minimum cross section, i.e. or

[0052] Here, the individual cross sections A opening_n result from the product of the defined height H and the minimum width B. The width of the respective opening against which the process seal rests is used as the width B. The pre-specified minimum cross section corresponds to a pre-specification from a standard, in particular the standards of the European Hygienic Engineering and Design Group (EHEDG) and / or 3-A (hygienic standards). In particular, the pre-specified minimum cross section corresponds to the standard 74-07 published in March 2019. For example, the pre-specified minimum cross section can have at least 4.9 square millimeters (mm 2 ), preferably at least 5 square millimeters (mm 2 ), and particularly preferably at least 7.2 square millimeters (mm 2 ).

[0053] List of reference signs

[0054] 100 pressure measurement unit

[0055] 200 housing

[0056] 210 housing adapter

[0057] 220 screw

[0058] 300 process connector

[0059] 310 stop surface

[0060] 320 geometry for receiving and securing a process seal

[0061] 330 opening for receiving a sensor cannula

[0062] 340 leak opening for notifying a process seal leak

[0063] 350 vertical recess

[0064] 360 back of the process connector

[0065] 370 front side of the process connector

[0066] 380 inner side surface of the process connector

[0067] 390 edge of the process connector, which is oriented towards a process seal and a stop surface for a sensor cannula

[0068] 400 sensor cannula

[0069] 410 upper portion of the sensor cannula

[0070] 420 shoulder loop

[0071] 421 hole

[0072] 430 lower portion of the sensor cannula

[0073] 431 outer side surface of the lower portion of the sensor cannula

[0074] 432 counter stop surface

[0075] 433 stop surface for a centering ring

[0076] 434 nose

[0077] 435 web

[0078] 436 vertical recess

[0079] 437 edge of the web, which is oriented towards a process seal

[0080] 438 lower collection groove

[0081] 439 upper collection recess

[0082] 500 pressure measurement cell

[0083] 510 body

[0084] 520 measurement diaphragm

[0085] 530 junction

[0086] 600 process seal

[0087] 700 centering ring

[0088] 710 short leg member of centering ring

[0089] 720 long leg member of centering ring

[0090] 800 opening that occurs in installed condition

[0091] H height of opening in installed condition

[0092] B width of opening in installed condition

[0093] EP1-EP4 individual exemplary fluid paths.

Claims

1. A pressure measuring cell for measuring a pressure, the pressure measuring cell having: - a pressure measuring cell (500); - a rotationally symmetrical sensor sleeve (400), into which the pressure measuring cell (500) is inserted; - a rotationally symmetrical process connector (300) for releasable fastening of the pressure measuring cell (100) to a wall of a measuring point, wherein a front side (370) of the process connector (300) has an inwardly extending circumferential stop surface (310) intended for the sensor sleeve (400), and a further end of the process connector (300) has an opening (330) for receiving the sensor sleeve (400), wherein, in the installed state, the sensor sleeve (400) together with the pressure measuring cell (500) is inserted into the process connector (300) through the opening (330) up to the stop surface (310) so that the pressure measuring cell (500) is introduced into the measuring point; - a ring-like process seal (600) which radially surrounds in ring-like fashion and seals in a sealing plane between the sensor sleeve (400) and the stop surface (310) of the process connector (300) in order to prevent penetration of process medium into the pressure measuring cell (100). - wherein the stop surface (310) of the process connector (300) and / or a counter stop surface (432) of the sensor sleeve (400) oriented towards the stop surface in the installed state has several individually formed web plates (435) designed such that, in the installed state, several openings (800) are formed between the counter stop surface (432) of the sensor sleeve (400) and the stop surface (310) of the process connector (300), the several openings (800) having a defined height (H) and width (B) defined by the configuration of the web plates, wherein the several openings (800) together form a fluid path network consisting of several individual fluid paths (EP1-EP4) continuing parallel to each other, via which fluid path network, in the event of failure of the process seal (600), the process medium is guided from the sealing plane in the process seal (600) to at least one leakage opening (340) which is externally visible in the installed state of the pressure measurement unit, wherein the web plates (435) are designed such that the sum of the individual cross sections of the several openings (800) corresponds to a pre-specified minimum cross section, wherein the defined height (H) and the defined width (B) are used to calculate the individual cross sections, and wherein depending on the properties of the process seal (600), the web plates are designed such that the process seal (600) does not extrude into the openings.

2. The pressure measurement unit of claim 1, wherein, The web plates (435) are designed such that the defined height (H) does not exceed a gap size pre-specified for the process seal (600).

3. The pressure measurement unit of claim 2, wherein, The web plates (435) are designed such that the defined height is less than 0.20 mm.

4. The pressure measurement unit of claim 3, wherein, The web plates (435) are designed such that the defined height is less than 0.15 mm.

5. The pressure measurement unit of claim 4, wherein, The web plates (435) are designed such that the defined height is less than 0.10 mm.

6. The pressure measurement unit of claim 5, wherein, The web plates (435) are designed such that the defined height is 0.08 mm.

7. The pressure measurement unit of any one of claims 1-6, wherein, The web plates (435) are arranged radially rearward from the process seal (600) such that, in the installed state, an edge (437) of the web plates oriented towards the process seal (600) does not come into contact with the process seal (600) which has not yet been extruded.

8. The pressure measurement unit of any one of claims 1-6, wherein, The outer side surface (431) of the sensor spool (400) in a lower partial area (430) thereof adjacent to the inner side surface (380) of the process connector (300) in the installed state and / or the inner side surface (380) of the process connector (300) in a lower partial area thereof adjacent to or of the outer side surface of the lower partial area of the sensor spool (400) in the installed state has several vertical recesses (436), wherein the several vertical recesses (436) are designed such that a cross-sectional sum of individual cross-sections of the several vertical recesses (436) corresponds to the pre-specified minimum cross-section.

9. The pressure measurement unit of claim 8, wherein, The sensor spool (400) has at least one circumferential lower collection groove (438) in the lower partial area (430) and / or the process connector (300) has at least one circumferential lower collection groove (438) in the lower partial area, the lower collection groove (438) serving to collect the process medium supplied via the several openings (800), wherein the lower collection groove (438) is designed such that a cross-section of the collection groove corresponds to the pre-specified minimum cross-section.

10. The pressure measurement unit of any one of claims 1-6, wherein, The sensor spool (400) has a circumferential shoulder ring (420), which in the installed state is inserted into the opening (330) of the process connector (300) up to the shoulder ring (420), and wherein the sensor spool (400) has a circumferential upper collection groove (439) directly adjacent to the shoulder ring (420) and designed to guide the process medium to the at least one externally visible leakage opening (340), wherein the upper collection groove (439) is designed such that a cross-section of the upper collection groove (439) corresponds to the pre-specified minimum cross-section.

11. The pressure measurement unit of any one of claims 1-6, wherein, The at least one externally visible leakage opening (340) is designed such that a cross-section or a cross-sectional sum corresponds to the pre-specified minimum cross-section.

12. The pressure measurement unit of claim 11, wherein, The at least one externally visible leakage opening (340) is formed on a rear side (360) of the process connector (300), on which in the installed state the shoulder ring (420) of the sensor spool (400) is fixed.

13. The pressure measurement unit of any one of claims 1-6, wherein, The pre-specified minimum cross-section corresponds to a standard pre-specification.

14. The pressure measurement unit of claim 13, wherein, The pre-specified minimum cross-section corresponds to a standard pre-specification related to European Hygienic Engineering Design Group and / or 3-A.

15. The pressure measurement unit of claim 14, wherein, The pre-specified minimum cross-section corresponds to a pre-specification of standard 74-07 of 3-A published in March 2019. The pre-specified minimum cross-section corresponds to a pre-specification of standard 74-07 of 3-A published in March 2019.

Images