阅读说明：本技术 现场设备的壳体盖 (Housing cover for field device ) 是由 维托朱塞佩·迪科索拉 于尔根·坦纳 亚历山大·斯托帕 京特·伊尔巴赫尔 于 2018-10-24 设计创作，主要内容包括：本发明涉及一种用于自动化技术的现场设备(1)的壳体盖(4),具有对应的壳体盖(4)的壳体(2),以及具有对应的壳体(2)的现场设备(1)。所述壳体盖(4)包括：-壳体盖本体(5),所述壳体盖本体(5)具有至少一个开口(5a),-观察窗(6),所述观察窗(6)能够被插入所述开口(5a)中,以及-紧固装置,所述紧固装置用于将所述壳体盖(4)尤其是以可释放的方式紧固在所述现场设备(1)的壳体(2)的壳体本体(3)上。根据本发明,所述观察窗(6)至少部分地由防冲击材料组成,尤其是玻璃(优选是铝硅酸盐玻璃)、陶瓷、或者玻璃或陶瓷与塑料的混合物。(The invention relates to a housing cover (4) for a field device (1) in automation technology, to a housing (2) having a corresponding housing cover (4), and to a field device (1) having a corresponding housing (2). The housing cover (4) includes: -a housing cover body (5), the housing cover body (5) having at least one opening (5a), -a viewing window (6), the viewing window (6) being insertable into the opening (5a), and-fastening means for fastening the housing cover (4), in particular in a releasable manner, on a housing body (3) of a housing (2) of the field device (1). According to the invention, the viewing window (6) is at least partially made of impact-resistant material, in particular glass (preferably aluminosilicate glass), ceramic, or a mixture of glass or ceramic and plastic.)

1. A housing cover (4) of an automation field device (1), the housing cover (4) comprising:

-a housing cover body (5), the housing cover body (5) having at least one opening (5a)

-a viewing window (6), said viewing window (6) being placeable in said opening (5a), and

-a fixing device for fixing the housing cover (4), in particular in a releasable manner, on a housing body (3) of a housing (2) of the field device (1),

the method is characterized in that:

the viewing window (6) is at least partially made of an impact-resistant material, in particular glass, preferably aluminosilicate glass, ceramic, or a mixture of glass or ceramic and plastic.

2. The housing cover (4) as claimed in claim 1, wherein the viewing window (6) is stuffed in the housing cover body (5).

3. Housing cover (4) according to claim 1 or 2, wherein the thickness of the viewing window (6) is at least 10 mm.

4. Housing cover (4) according to at least one of the preceding claims, wherein the viewing window (6) consists of at least a first window panel (7) and a second window panel (8).

5. Housing cover (4) according to claim 4, wherein a first window pane (7) of the two window panes consists at least partially of heat-resistant glass, in particular borosilicate glass.

6. Housing cover (4) according to claim 4 or 5, wherein the second of the two pane (8) is at least partially composed of an impact-resistant material, in particular glass, preferably aluminosilicate glass, ceramic, or a mixture of glass or ceramic and plastic.

7. Housing cover (4) according to at least one of claims 4 to 6, wherein the two window panels (7, 8) are arranged in such a way that: so that the second window pane (8) faces outwards.

8. Housing cover (4) according to at least one of claims 4 to 7, wherein the two window panels (7, 8) have different thicknesses (h)₁、h₂) In particular the thickness (h) of the first pane (7)₁) At least 10mm, the thickness (h) of the second pane (8)₂) Less than or equal to 5 mm.

9. Housing cover (4) according to at least one of claims 4 to 8, wherein the first pane (7) and the second pane (8) are at least partially connected together.

10. Housing cover (4) according to claim 9, wherein the connection is produced by a bonding method or wherein the connection is produced by an adhesive (9), in particular a transparent adhesive (9).

11. Housing cover (4) according to at least one of claims 4 to 10, wherein the two window panels (7, 8) have an area (a) which is not equally large₁、A₂) In particular with different diameters (d)₁、d₂)。

12. Housing cover (4) according to claim 11, wherein the areas (a) of the two window panels (7, 8)₁、A₂) Are aligned with each other, wherein the area (a) of the second window panel (8)₂) Is smaller than the area (A) of the first window panel (7)₁) And wherein an edge region (10), in particular a rounded edge region (10), of the first window panel (7) is not covered by the second window panel (8).

13. Housing cover (4) according to at least one of the preceding claims, the housing cover (4) being implemented in such a way that: making the housing cover (4) suitable for use in explosion-hazard environments.

14. Housing (2) for a field device (1), the housing (2) having a housing cover (4) according to at least one of the preceding claims.

15. An automation field device (1) comprising a sensor element, field device electronics and a housing (2) according to claim 14.

Technical Field

The invention relates to a housing cover for a field device in automation technology, in particular for a housing of such a field device, and to a housing having a housing cover according to the invention and to a field device having a housing according to the invention.

Background

Automation-related field devices are, for example, water level measuring devices, flow meters, pressure and temperature measuring devices, pH measuring devices and/or pH redox potential measuring devices, and even conductivity measuring devices, which record corresponding process variables, namely water level, flow, pressure, temperature, pH value, redox potential and conductivity. The basic measurement principles are well known in the art and are not separately set forth herein. In the case of flow meters, these are, in particular, Coriolis (Coriolis), ultrasonic, vortex, thermal and/or magnetic induction flow meters. The water level measuring device is in particular a microwave water level measuring device, an ultrasonic water level measuring device, a time domain reflectometer water level measuring device (TDR), a radiometric water level measuring device, a capacitive water level measuring device, an inductive water level measuring device and/or a temperature-sensitive water level measuring device. In contrast, in the case of pressure measuring devices, these are preferably so-called absolute pressure devices, relative pressure devices or differential pressure devices, while temperature measuring devices generally use thermocouples or temperature-dependent resistors for determining the temperature.

Fundamentally, a field device usually comprises at least one sensor unit which is at least partially and at least from time to time in contact with the process, and an electronics unit, for example for signal recording, evaluation and/or feeding. In the context of the present invention, in principle all measuring devices are referred to as field devices, which are used in the vicinity of the process and communicate or process-related information, and therefore also include remote I/O, radio adapters and generally also electronic components arranged in the field. The Enaddress + Hauser group company produces and sells a large number of such field devices.

At least the electronics unit of such field devices is usually arranged in a housing. Depending on the type of field device, and thus the process variable to be determined and/or monitored, and/or depending on the intended application or use of the field device, various embodiments are possible for the field device housing. In particular, different applications have different requirements for the housing of the field device. Therefore, for a housing used in an explosion-hazard environment, in addition to the conditions that need to be taken into account when applied, for example, in the chemical industry, the food industry, and the like, other conditions need to be taken into account. For housings used in explosion-hazard environments, particular care is taken to safely prevent the formation of sparks or at least to ensure that sparks occurring in the event of a fault do not affect the environment. In this case, the person skilled in the art can basically distinguish between different types of explosion protection and explosion regions. For example, different requirements are in turn described in the european ATEX or north american NEC or CEC commands and in the standards EN, IEC, UL, CSA or NEC based thereon.

The components of field devices that can trigger ignition are, for example, usually mounted in a pressure-tight housing that can withstand the pressure generated in the event of an explosion. Thus, the propagation of the explosion is in principle prevented by a suitable housing structure. For this purpose, an explosion-proof type "pressure-resistant packaging" (Ex-d) is used, which provides the structural requirements for the housing in the following manner: so that the explosion cannot escape from the interior of the housing. For example, according to the region, detailed information about these requirements is given in the standards EN60079-1, IEC 60079-1, UL2279PT.1, UL60079-1 and CSA E60079-1.

Typically, the components of the field device are disposed in a housing body that forms a cavity. The housing body can be closed by a housing cover. In order to ensure sufficient mechanical stability in the event of an explosion, such housings have relatively thick housing walls and are therefore relatively expensive. Furthermore, display elements for displaying measured values or the like and interaction elements for field adjustment of the settings of the field devices have to be arranged in the housing or in separate housing parts in the explosion-hazard area. Correspondingly, the housing cover usually has a viewing window, which, for example, enables the display element to be read. Furthermore, the interaction element can be provided, for example, by means of an optical key, which can be actuated through the viewing window. In order to ensure a high mechanical stability or stability under pressure of the housing cover with the viewing window, in particular with respect to impact tests, the high requirements with regard to construction must be followed. For example, the viewing window is typically padded in the housing cover. Furthermore, there are various requirements for the material and thickness of the viewing window.

A pressure-tight housing is known, for example, from DE102004052497a1, in which case the display element is surrounded on all sides by a pressure-tight transparent potting compound. In this case, however, the complete housing cover with integrated display element must be replaced if it is damaged.

Disclosure of Invention

It is therefore an object of the present invention to provide a housing cover with an integrated viewing window, in the case of which an improved mechanical stability can be achieved in a simple manner.

This object is achieved by a housing cover as defined in claim 1, a housing as defined in claim 14 and a field device as defined in claim 15.

With regard to the housing cover, the object of the invention is achieved by a housing cover for a field device in automation technology, comprising:

a housing cover body having at least one opening,

-a viewing window, which can be placed in the opening, and

the fastening device is used for fastening the housing cover, in particular in a releasable manner, to a housing body of a housing of the field device.

According to the invention, the viewing window is at least partially composed of an impact-resistant material, in particular glass (preferably aluminosilicate glass), ceramic, or a mixture of glass or ceramic and plastic.

Since the impact resistance is increased, an increase in mechanical stability can be ensured. The corresponding housing cover is therefore very suitable for use in explosion-hazard areas. In particular, the corresponding housing cover is able to withstand impact tests up to 4J and subsequent pressure loads of more than 80 bar. In the case of conventional glasses, impact tests often lead to so-called microcracks, which can adversely affect the stability of the glass under pressure.

Aluminosilicate glasses are characterized by, for example, particularly high resistance to cracking and scratching compared to other glasses. In particular, the aluminosilicate glass can be a chemically prestressed aluminosilicate glass, in which case sodium ions in the glass surface are replaced by potassium ions during ion exchange in a heated potassium salt melt (at about 400 ℃). This results in a glass that is crack resistant at a point load of 40N or greater and that has a scratch resistance that is at least two to three times that of conventional glasses.

In one embodiment, the viewing window is padded (populated) for connection with the housing cover body. The viewing window is then in principle framed into the housing cover body in a predetermined edge region. The plugging of the viewing window into the housing cover is particularly advantageous in view of the requirements of explosion protection class Ex-d.

Furthermore, it is advantageous if the viewing window has a thickness of at least 10 mm.

In a particularly preferred embodiment, the observation window consists of at least a first (pane) and a second pane. Preferably, the first and second window panels are superimposed on one another. For example, the first and second window panels can be composed of different materials having different properties, in particular different mechanical properties. For a pressure-resistant package corresponding to explosion-proof class Ex-d, for example, it is required that the observation window can withstand a pressure load after being exposed to an impact load. Mechanical shock loads may especially cause microcracks at least in the area close to the surface of the window. These microcracks play an adverse role in the case of subsequent high-pressure loading. Due to the use of two window panes, the different requirements to be met in relation to high crack and scratch resistance and high stability under pressure loading can be set up in a targeted manner. For example, a first pane facing the interior of the housing can have a high pressure resistance, while a second pane facing the exterior of the housing can have an improved resistance to crack formation and scratch formation.

It is therefore advantageous if the first of the two window panes consists at least partially of heat-resistant glass, in particular borosilicate glass. Borosilicate glasses are therefore characterized by a high chemical durability, which is likewise a fundamental advantage, and they have a relatively small coefficient of thermal expansion. Therefore, in the case of the first window panel, it is preferable to ensure a window panel having high stability when facing a pressure load.

Likewise or alternatively, the second of the two panes is advantageously composed at least partially of an impact-resistant material, in particular glass (preferably aluminosilicate glass), ceramic, or a mixture of glass or ceramic and plastic. The second pane is then used to ensure a high resistance to scratch formation and/or crack formation.

Preferably, the two window panels are arranged in such a way that: so that the second window panel faces outwardly. Thus, the second window panel having high scratch formation resistance and/or crack formation resistance faces the outside of the housing, while the first heat-resistant window panel for ensuring high resistance to pressure load faces the inside of the housing.

Another preferred embodiment provides: the two window panels have different thicknesses, in particular the first window panel has a thickness of at least 10mm and the second window panel has a thickness of less than or equal to 5 mm. Therefore, it is preferable that the thickness of the second pane for preventing the formation of scratches and/or cracks is smaller than the thickness of the first pane.

Advantageously, the first window panel and the second window panel are at least partially connected together. In this way, an increase in the stability of the housing cover can be achieved.

Preferably, the connection is produced by a bonding method or by an adhesive, in particular a transparent adhesive. The adhesive is preferably composed of at least one layer of a composite material that is durable in elasticity. The adhesives concerned can be, for example, so-called film bonds (optically clear adhesives, OCAs) or liquid bonds (liquid optically clear adhesives, LOCAs). Examples include silicone adhesives. The adhesive can be applied, for example, locally in the annular edge region between the two window panes or completely at the interface between two mutually facing surface regions of the two window panes. The viscosity of the adhesive is advantageously selected such that the formation of air bubbles between the two window panels is substantially prevented.

Another particularly preferred embodiment provides: the two window panels have areas which are not equally large, in particular have different diameters.

In this connection, it is advantageous if the center points of the areas of the two window panels are aligned with one another, wherein the area of the second window panel is smaller than the area of the first window panel, and wherein the, in particular circular, edge region of the first window panel is not covered by the second window panel. By means of this annular edge region, the viewing window can be installed, for example, into the housing cover body.

On the one hand, the two window panels can first be connected together and then introduced into the housing cover body. On the other hand, it is also possible to first introduce the first window panel into the housing cover body, fix it, for example by caulking, and then connect the second window panel to the first window panel, for example by gluing. In this way, for example, existing housing covers of the invention can be retrofitted for increasing the mechanical stability of use, in particular in explosion-hazard environments.

In one embodiment, the housing cover is implemented in such a way that: making it suitable for use in explosion-hazard environments.

The object of the invention is also achieved by a housing for a field device having a housing cover according to the invention and by a field device according to automation technology, which comprises a sensor element, field device electronics and a housing according to the invention.

It should be noted here that the embodiments described for the housing cover can also be used, mutatis mutandis, for the housing of the invention and for the field device of the invention, and vice versa.

Drawings

The invention will now be explained in more detail on the basis of the drawings, in which like elements are provided with like reference numerals. The figures in the drawings are as follows:

figure 1 is a schematic view of a housing with a housing cover of the present invention,

fig. 2 is a first embodiment of the inventive housing cover with a viewing window consisting of two window panels, an

Fig. 3 shows a second exemplary embodiment of a housing cover according to the invention with a viewing window consisting of two window panels.

Detailed Description

Fig. 1 shows a housing 2 of a field device 1 (not shown) for automation technology. The housing 2 comprises a housing body 3 with a cavity, in which housing body 3 at least one component of the field device 1, for example an electronics unit (not shown), is arranged. The housing body 3 is closed by a housing cover 4, which housing cover 4 contains a viewing window integrated therein. Behind the viewing window can be, for example, a display element or an interactive element, in particular an optical interactive element. The housing cover 4 is connected to the housing body in a known manner. For example, in this respect, a screw connection or a flange connection can be employed. The housing 2 is made of metal or plastic, for example.

The housing cover 4 includes a housing cover body 5 having an opening 5a, and a viewing window 6 is fixed in the opening 5 a. For example, the observation window 6 is caulked in the case lid body 5. The viewing window 6 is then framed in principle in the inner edge region of the housing cover body 5. According to the invention, the viewing window is at least partially composed of an impact-resistant material, in particular glass (preferably aluminosilicate glass), ceramic, or a mixture of glass or ceramic and plastic.

The viewing window 6 may on the one hand be a single element as shown in fig. 1. Alternatively, however, the viewing window can also consist of at least two window panes 7, 8, as shown in fig. 2 and 3.

Fig. 2 shows a viewing window 6 composed of a first window panel 7 and a second window panel 8. In this embodiment, the thickness h of the second window panel 8₂Is smaller than the thickness h of the first window pane 7₁. The second pane 8 is at least partially composed of an impact-resistant material, in particular glass (preferably aluminosilicate glass), ceramic, or a mixture of glass or ceramic and plastic, and the first pane is composed of heat-resistant glass, in particular borosilicate glass. In this case, the first pane 7 faces the housing interior and the second pane 8 points outward. The second pane 8 ensures a high resistance of the observation window 6 against the formation of scratches and/or cracks and thus a high mechanical stability against impacts. The first pane 7 is characterized by a high degree of stability under pressure, in particular in the event of an explosion inside the housing under the given circumstances. The two window panes 7, 8 are preferably joined together, for example by a joining method or by means of an adhesive, in particular a transparent adhesive.

In the example of embodiment shown in fig. 2, the first window panel 7 and the second window panel 8 have substantially the same area. In contrast, in the exemplary embodiment shown in fig. 3, the diameter d of the second window pane 8₂Is smaller than the diameter d of the first window pane 7₁. Two areas A₁And A₂Are aligned with each other in such a way that: so that the annular edge region 10 of the first window panel 7 is not covered by the second window panel 8. The viewing window 6 can be mounted, for example, in the housing cover body 5 with this annular edge region.

Alternatively, it is also possible to first install only the first window panel 7 in the housing cover body 5 and then apply the second window panel 8 to the first window panel 7. For this purpose, the second window panel 8 can be bonded to the first window panel 7, for example, by means of an adhesive 9. However, other known securing means can be used and fall within the scope of the invention. In this way, for example, an existing housing cover 4 can be retrofitted according to the invention.

Reference numerals

1 field device

2 casing

3 casing body

4 casing cover

5 housing cover body with opening 5a

6 Observation window

7 first pane panel

8 second pane

9 adhesive

10 annular edge region

h₁、h₂Thickness of the window panels 7, 8

d₁、d₂Diameter of the window pane 7, 8

A₁、A₂Area of window panels 7, 8