Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention and not to limit the invention.
FIG. 1 is a schematic view, partly in section, of a radar level gauge according to an embodiment of the present invention;
FIG. 2 is a schematic view, partly in section, of another angle of the radar level gauge shown in FIG. 1;
FIG. 3 is an exploded schematic view of the radar level gauge shown in FIG. 1;
FIG. 4 is a schematic view of the structure of an insulating sleeve of the radar level gauge shown in FIG. 1.
Reference numerals:
1-shell, 11-installation through hole, 12-second injection molding joint surface, 13-positioning groove, 2-insulating sleeve, 21-installation cavity, 22-first injection molding joint surface, 23-axial positioning part, 24-circumferential positioning part, 25-step surface, 3-circuit board, 4-shielding cover, 41-through hole, 42-screw column, 5-positioning screw, 6-sealing ring, 7-sealant, 8-wave absorbing material and 9-fastening screw.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Embodiments of the present invention provide a radar level gauge, as illustrated in FIGS. 1-4.
The radar level meter comprises a meter head, wherein the meter head comprises a shell 1 and a radiation module arranged in the shell 1, the meter head further comprises an insulating sleeve 2, a mounting through hole 11 used for mounting the insulating sleeve 2 is formed in the shell 1, the insulating sleeve 2 and the shell 1 are integrally formed through an insert injection molding process, a mounting cavity 21 with an opening at one end is formed in the insulating sleeve 2, and the opening of the mounting cavity 21 faces the outer side of the shell 1.
Specifically, when the insulating sleeve 2 is injection molded with the housing 1, the insulating sleeve 2 is injection molded into the housing 1 as an insert. An installation cavity 21 with an opening at one end is arranged on the insulating sleeve 2, and a waveguide body of the radar level meter can extend into the installation cavity 21 to realize the matched installation with the insulating sleeve 2. In the injection molding process, the mounting cavity 21 of the insulating sleeve 2 can be matched with a positioning fixing piece in a mold so as to fix the insulating sleeve 2 in the mold and facilitate injection molding.
In the radar level gauge provided by the embodiment of the invention, the shell 1 and the insulating sleeve 2 of the gauge head are integrally formed by insert injection molding technology, so that the insulating sleeve 2 and the shell 1 are firmly connected without loosening, no gap exists between the installation through hole 11 of the shell 1 and the insulating sleeve 2, the sealing performance of the gauge head of the radar level gauge is improved, and the radar level gauge meets the explosion-proof performance.
Optionally, the housing 1 is filled with a sealant 7 to enhance the sealing performance of the housing 1. The sealant 7 may be silicone gel or other glue.
Optionally, a first injection-molded joint surface 22 is disposed on the outer surface of the insulating sleeve 2, a second injection-molded joint surface 12 that is joined to the first injection-molded joint surface 22 is disposed on the inner surface of the mounting through hole 11, and a positioning portion for positioning the first injection-molded joint surface 22 and the housing 1 is disposed on the first injection-molded joint surface 22.
The insulating sleeve 2 and the shell 1 are integrally formed through an insert injection molding process, and the insulating sleeve 2 and the shell 1 are fixedly connected integrally through the combination of the first injection molding joint surface 22 and the second injection molding joint surface 12. The positioning portion on the first injection-molded joint surface 22 can be used for positioning the housing 1, and is helpful for realizing the firm joint between the insulating sleeve 2 and the housing 1 and preventing the relative displacement between the two.
Optionally, a first injection-molded joint surface 22 is provided on the outer circumferential surface of the insulating sleeve 2, a second injection-molded joint surface 12 is provided on the inner circumferential surface of the mounting through hole 11, and the positioning portion includes an axial positioning portion 23 and a circumferential positioning portion 24.
Alternatively, the axial positioning portion 23 includes an annular groove or an annular protrusion provided on the outer peripheral surface of the insulating sleeve 2, and the circumferential positioning portion 24 includes a positioning groove or a positioning protrusion provided on the outer peripheral surface of the insulating sleeve 2.
The axial positioning portion 23 can be used for realizing axial positioning of the insulating sleeve 2 and the housing 1, and the circumferential positioning portion 24 can be used for realizing circumferential positioning of the insulating sleeve 2 and the housing 1, so as to prevent the insulating sleeve 2 and the housing 1 from relative axial movement or rotation.
Alternatively, the housing 1 and the insulating sheath 2 may be made of different materials. Such as: the housing 1 can be made of common plastic, and the insulating sheath 2 can be made of Polytetrafluoroethylene (PTFE), Fluorinated Ethylene Propylene (FEP) or Perfluoroalkylfluoride (PFA).
Because the price of PTFE, FEP and PFA is more expensive than that of common plastics, the insulating sleeve 2 is made of PTFE, FEP and PFA, the shell 1 is made of common plastics, and the two materials are combined, so that the transmission of electromagnetic waves radiated by the radiation module is met, and the whole price is relatively low.
Alternatively, the radiation module includes a circuit board 3, a shielding case 4 fixed on the circuit board 3, and a radiation element mounted on the circuit board 3, the shielding case 4 and the circuit board 3 cooperate to form a shielding cavity, and the radiation element is located in the shielding cavity, so that the shielding case 4 can cover the radiation element. The surface of the shielding cover 4 which encloses the shielding cavity can be provided with wave-absorbing material 8.
A through hole 41 is formed in the shield case 4, and a bottom wall of the mounting cavity 21 (opposite to the opening of the mounting cavity 21) extends into the through hole 41 of the shield case 4. The electromagnetic wave emitted by the radiation element can pass through the through hole 41 on the shielding case 4 and the insulating sleeve 2 and enter the wave guide channel in the wave guide body.
Alternatively, the shield case 4 and the circuit board 3 are fixed by fastening screws 9. Of course, the shield case 4 and the circuit board 3 may be fixed by other means.
Optionally, the shielding case 4 and the housing 1 are positioned by a positioning element, a positioning through hole 41 for the positioning element to pass through is formed in the housing 1, and a positioning blind hole for connecting with the positioning element is formed in the shielding case 4.
When the positioning piece is used to position the shielding case 4 and the housing 1, the positioning piece first passes through the positioning through hole 41 on the housing 1 and then extends into the positioning blind hole of the shielding case 4. After the shield case 4 is positioned with the housing 1, the sealant 7 may be filled into the housing 1. In the use process of the radar level gauge, even if the fixing piece is detached or loosened, the positioning blind hole does not completely penetrate through the shielding cover 4, so that external gas, dust, impurities and the like can be prevented from entering the shielding cavity, and the sealing performance and the explosion-proof performance of the gauge outfit are ensured.
Alternatively, the screw post 42 is provided on the shield case 4, the positioning groove 13 is provided on the inner wall surface of the housing 1, and the screw post 42 extends into the positioning groove 13. The positioning blind hole can be a blind hole with internal threads arranged on the screw column 42, the positioning piece is a positioning screw 5, and the positioning screw 5 is screwed with the positioning blind hole after penetrating through the positioning through hole 41 on the shell 1.
Optionally, a step surface 25 is formed on the outer side wall surface of the insulating sleeve 2, a sealing ring 6 is sleeved on the insulating sleeve 2, and the sealing ring 6 is tightly pressed between the step surface 25 and the shielding cover 4.
The sealing ring 6 is arranged, so that external gas, dust, impurities and the like are prevented from entering the shielding cavity from the gap between the insulating sleeve 2 and the shielding cover 4, and the sealing performance and the explosion-proof performance of the gauge outfit are ensured.
In the description of the embodiments of the present invention, unless explicitly stated or limited otherwise, the terms "connected," "fixed," "mounted," and the like are to be construed broadly, e.g., the term "connected" may be a fixed connection, a detachable connection, or an integral connection; the two components can be directly connected or indirectly connected through an intermediate medium, and the two components can be communicated with each other; either mechanically or electrically. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Although the embodiments disclosed in the present application are described above, the descriptions are only for the convenience of understanding the present application, and are not intended to limit the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.