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CN-115371764-B - Liquid level transmitter and manufacturing method thereof

CN115371764BCN 115371764 BCN115371764 BCN 115371764BCN-115371764-B

Abstract

The invention belongs to the technical field of transmitters, and discloses a liquid level transmitter and a manufacturing method thereof. The pressure sensor is arranged between the protective cap and the transformation circuit, one end of the pressure sensor is fixedly connected with the protective cap, the other end of the pressure sensor is connected with the transformation circuit, a circular metal shell is arranged on the outer side of the transformation circuit, the transformation circuit is connected with the transformation circuit in the circular metal shell through a transmission plate, and the cable packaging unit is arranged on the other side of the transmitter and is fixedly connected with the metal shell. The structure and the method for manufacturing the liquid level transmitter simplify the process and the assembly flow of the liquid level transmitter, reduce the outer diameter of the liquid level transmitter, have better sealing performance and more accurate detection result of the liquid level transmitter.

Inventors

  • YANG XI
  • LIU MINGQIANG
  • LI XINGWANG
  • YANG LIANG
  • ZHAO YANXIA
  • YANG ENJIANG

Assignees

  • 天水华天传感器有限公司

Dates

Publication Date
20260505
Application Date
20220819

Claims (8)

  1. 1. A liquid level transmitter is characterized by comprising a protective cap (11), a pressure sensor, a conversion circuit and a cable packaging unit, wherein, The protective cap (11) is of a cylindrical structure, and the protective cap (11) is arranged on one side of the liquid level transmitter and is connected with the pressure sensor; the pressure sensor is arranged between the protective cap (11) and the conversion circuit, one end of the pressure sensor is fixedly connected with the protective cap (11), and the other end of the pressure sensor is connected with the conversion circuit; the outer side of the transformation circuit is provided with a round metal shell, and the transformation circuit is connected with a cable in the cable packaging unit through a wire in the round metal shell; the cable packaging unit is arranged on the other side of the liquid level transmitter and is fixedly connected with the metal shell; the pressure sensor comprises a base (26), an isolating corrugated diaphragm (22), a conducting medium (23), a tube seat (27), a pressure chip (28) and a compensation plate (29), wherein, One end of the base (26) is a closed end, the other end of the base is an open end, a first through hole penetrating through is formed in the centers of the open end and the closed end, a hollow boss is arranged in the open end, and a diaphragm connecting piece (21) with an annular structure is welded on the end face of the closed end; The conductive medium (23) is arranged in the first through hole; The isolation corrugated membrane (22) is fixedly arranged in the annular area of the membrane connecting piece (21) with the annular structure and is fixedly connected with the end face of the closed end of the base (26); The tube seat (27) is fixedly arranged on the hollow boss table top, a ceramic seat (25) is arranged in the hollow boss of the base (26), and one end face of the ceramic seat is contacted with the ceramic seat (25); the pressure chip (28) is fixedly arranged in the hollow boss; the compensating plate (29) is arranged at a port of the open end and is fixedly connected with the base (26) through a pin (271); The center of the tube seat (27) is provided with a through second through hole, a vent pipe (272) is fixedly arranged on the second through hole, a plurality of pins (271) and medium injection holes (273) are uniformly arranged around the second through hole, one ends of the pins (271) are fixedly arranged on the tube seat (27), the other ends of the pins penetrate through the compensation plate (29) and are fixedly connected with the compensation plate (29), the pins (271) are connected with the pressure chip (28) through a bonding alloy wire (24), and hole sealing pieces (274) are arranged on the medium injection holes (273); The conversion circuit comprises a conversion circuit shell, and a transmission plate (31), an insulating sleeve (32), an air ventilation sleeve (34) and a sleeve (35) which are arranged in the conversion circuit shell, wherein the transmission plate (31) is fixedly arranged in the insulating sleeve (32), one end of the air ventilation sleeve (34) is connected with an air pipe (272) on a pipe seat (27), the other end of the air ventilation sleeve faces to a cable packaging unit, one end of the transmission plate (31) is connected with a pin (271) through an input wire, and potting adhesive (33) is filled in the conversion circuit shell.
  2. 2. The fluid level transmitter of claim 1, wherein the protective cap (11) comprises a protective cap body, a filter screen (12), a retainer ring, and an O-shaped rubber ring, wherein, The protective cap body is of a hollow cavity structure, the retainer ring is arranged in the cavity, one end of the protective cap body is a closed end, the other end of the protective cap body is an open end, external threads are arranged on the outer circular surface of the open end, and a penetrating liquid inlet (111) is formed in the protective cap body between the open end and the closed end; the filter screen (12) is arranged in the cavity and is positioned at one side of the check ring; the O-shaped rubber ring is sleeved at the bottom of the external thread.
  3. 3. A liquid level transmitter according to claim 2, characterized in that the number of said liquid inlet holes (111) is four, four of said liquid inlet holes (111) are evenly distributed on said protective cap (11) body, and four of said liquid inlet holes (111) are located between said filter screen (12) and the closed end of said protective cap (11).
  4. 4. A fluid level transmitter according to claim 1, characterized in that the conductive medium (23) is silicone oil.
  5. 5. The liquid level transmitter according to claim 1, wherein a second through hole penetrating through is formed in the center of the tube seat (27), a vent pipe (272) is fixedly arranged on the second through hole, a plurality of pins (271) and medium injection holes (273) are uniformly formed around the second through hole, one ends of the pins (271) are fixedly arranged on the tube seat (27), the other ends of the pins penetrate through the compensation plate (29) and are fixedly connected with the compensation plate (29), the pins (271) are connected with the pressure chip (28) through bond wires (24), and hole sealing pieces (274) are arranged on the medium injection holes (273).
  6. 6. The fluid level sender of claim 5, wherein said hole sealing member (274) is a stainless steel ball.
  7. 7. The liquid level transmitter according to claim 1, wherein the cable packaging unit comprises a wire sealing sleeve (44) and a rubber sheath (46), one end of the rubber sheath (46) is a fixed end, the other end of the rubber sheath is a free end, the fixed end of the rubber sheath (46) is detachably connected with the wire sealing sleeve (44), through holes which are concentrically distributed and are used for allowing a ventilation cable (47) to pass through are respectively arranged in the centers of the wire sealing sleeve (44) and the rubber sheath (46), and a first rubber ring (41), a wire sealing gasket (42), a second rubber ring (43) and a wire sealing fastener (45) are sequentially arranged between the wire sealing sleeve (44) and the rubber sheath (46).
  8. 8. A method of manufacturing a fluid level transmitter as defined in any one of claims 1-7, comprising, S1, bonding a ceramic seat (25) and a pressure chip (28) on a tube seat of a pressure sensor unit, and electrically connecting a pin (271) on the tube seat (27) with the pressure chip (28) through a bond alloy wire (24); S2, arranging a base (26) on one side of a tube seat of the pressure sensor unit, arranging a conversion circuit on the other side, injecting a conductive medium (23) into a medium injection hole (273) of the base (26), sealing the medium injection hole (273) by using a hole sealing piece (274), welding a compensation plate (29) on a pin (271), electrically connecting the compensation plate (29) with a transmission plate (31) in a shell of the conversion circuit by using a wire, arranging an insulating sleeve (32) in a sleeve (35) of the conversion circuit, and simultaneously filling potting adhesive (33) in the insulating sleeve (32); S3, arranging a wire sealing sleeve (44) and a rubber sheath (46) on the other side of the conversion circuit, wherein a first rubber ring (41), a wire sealing gasket (42), a second rubber ring (43) and a wire sealing fastener (45) are sequentially arranged between the wire sealing sleeve (44) and the rubber sheath (46); And S4, arranging a protective cap (11) on the other side of the pressure sensor, arranging a filter screen (12) and a hole retainer ring (13) in the protective cap (11), arranging an O-shaped rubber ring (14) at the bottom of a thread of the protective cap (11), and connecting the protective cap (11) on a diaphragm connecting piece (21) in a threaded manner to finish the manufacturing of the liquid level transmitter.

Description

Liquid level transmitter and manufacturing method thereof Technical Field The invention belongs to the technical field of transmitters, and particularly relates to a liquid level transmitter and a manufacturing method thereof. Background The silicon piezoresistive pressure sensor is widely applied because of high sensitivity, low cost and precision meeting most measurement requirements, and the liquid level transmitter is one of meters developed by utilizing the characteristics of the silicon piezoresistive pressure sensor. In the aspect of liquid level detection application, the liquid level transmitter developed by utilizing the silicon piezoresistive pressure sensor is widely applied due to the advantages of high sensitivity, low cost, convenience in use and the like. The liquid level transmitter measured in the current market has various varieties and can realize the liquid level measurement function with high precision. The oil filling core pressure sensor is realized through a shell assembly or welding process, the pressure sensor is sleeved with the shell, and the pressure sensor is matched with a corresponding conversion circuit of the pressure sensor and a cable sealing ring in the shell to form the integral liquid level transmitter, but the pressure sensor is required to be placed in the shell where the conversion circuit is located in the assembly process, so that the diameter of the shell of the liquid level transmitter is overlarge, the process cost of assembly and the like is increased, and the sealing effect of the cable sealing ring of part of the liquid level transmitter is poor, so that a larger error exists in the detection result of the liquid level transmitter. Disclosure of Invention The invention aims to provide a liquid level transmitter and a manufacturing method thereof, which are used for solving the problems in the prior art; in order to achieve the above purpose, the present invention adopts the following technical scheme: A liquid level transmitter, includes helmet, pressure sensor, transform circuit and cable encapsulation unit, wherein: the protective cap is of a cylindrical structure, is arranged on one side of the liquid level transmitter and is connected with the pressure sensor; the pressure sensor is arranged between the protective cap and the conversion circuit, one end of the pressure sensor is in threaded connection with the protective cap, and the other end of the pressure sensor is connected with the conversion circuit; the outer side of the transformation circuit is provided with a round metal shell, and the transformation circuit is connected with a cable in the cable packaging unit through a wire in the round metal shell; the cable packaging unit is arranged on the other side of the transmitter and fixedly connected with the metal shell. Further, the protective cap comprises a protective cap body, a filter screen, a retainer ring and an O-shaped rubber ring, wherein, The protective cap body is of a hollow cavity structure, the retainer ring is arranged in the cavity, one end of the protective cap body is a closed end, the other end of the protective cap body is an open end, external threads are arranged on the outer circular surface of the open end, and a penetrating liquid inlet is formed in the protective cap body between the open end and the closed end; The filter screen is arranged in the cavity and is positioned at one side of the check ring; the O-shaped rubber ring is sleeved at the bottom of the external thread. Further, the number of the liquid inlet holes is four, the four liquid inlet holes are uniformly distributed on the protective cap body, and the four liquid inlet holes are positioned between the filter screen and the closed end of the protective cap. Further, the pressure sensor comprises a base, an isolation bellows diaphragm, a conductive medium, a tube holder, a pressure chip and a compensation plate, wherein, One end of the base is a closed end, the other end of the base is an open end, a first through hole penetrating through is formed in the centers of the open end and the closed end, a hollow boss is arranged in the open end, and a diaphragm connecting piece with an annular structure is welded on the end face of the closed end; the conductive medium is arranged in the first through hole; the isolation corrugated membrane is fixedly arranged in the annular area of the membrane connecting piece with the annular structure and is fixedly connected with the end face of the closed end of the base; The tube seat is fixedly arranged on the hollow boss table surface, a ceramic seat is arranged in the hollow boss of the base, and one end face of the tube seat is contacted with the ceramic seat; the pressure chip is fixedly arranged in the hollow boss; the compensation plate is arranged at a port of the open end and is fixedly connected with the base through a pin. Further, the conductive medium is silicone oil. Further, a through second through hole