CN107436166A - Transducer for ultrasonic flowmeter - Google Patents

Abstract

The invention discloses a transducer for an ultrasonic flowmeter, which comprises a casing provided with a mounting hole, an acoustic matching layer and a piezoelectric element sequentially installed in the mounting hole, and a transducer sealingly connected with the casing with one end pressed against the casing. On the base of the piezoelectric element, the piezoelectric element and the acoustic matching layer are sealed between the shell and the base; the base includes a cylinder and a square mounting plate integrally formed with the cylinder, and the mounting plate It is fixed to the ultrasonic flowmeter by screws. The base of the present invention includes a cylinder and a square mounting plate integrally formed with the cylinder. Through the base structure, the mounting plate is fixed to the ultrasonic flowmeter by screws. Compared with the existing base and ultrasonic flowmeter The direct thread connection reduces the length of the base, thereby reducing the occupied space of the transducer and facilitating installation. The double matching layer structure formed by the acoustic matching layer and the housing improves the conversion efficiency of the piezoelectric element and ensures a better sound wave transmission coefficient.

Description

Transducer for ultrasonic flowmeter

technical field

The invention relates to the technical field related to transducers, in particular to a transducer for an ultrasonic flowmeter.

Background technique

Ultrasonic flow meters are instruments that measure flow by detecting the effect of fluid flow on ultrasonic beams or ultrasonic pulses. The ultrasonic flowmeter is mainly composed of an ultrasonic transducer (or an ultrasonic flow sensor composed of a transducer and a measuring tube) installed on the measuring pipe and a converter.

The transducer is a device that converts electrical energy, mechanical energy or sound energy from one form of energy to another form of energy. Transducers are one of the important components of ultrasonic flowmeters. The existing transducers are large in size, so they take up a lot of space when installed, and the transducers that occupy a small space have low measurement accuracy and low conversion efficiency. Meet the actual use needs. Therefore, there is an urgent need for an ultrasonic transducer that occupies less space and has high conversion efficiency.

Contents of the invention

The object of the present invention is to provide an ultrasonic flow transducer to solve the problems of large occupied space and low conversion efficiency of existing transducers.

For reaching this purpose, the present invention adopts following technical scheme:

A transducer for an ultrasonic flowmeter, comprising a housing provided with a mounting hole, an acoustic matching layer and a piezoelectric element sequentially installed in the mounting hole, and a piezoelectric element sealedly connected with the housing and one end pressed against the piezoelectric element The base, the piezoelectric element and the acoustic matching layer are sealed between the shell and the base; the base includes a cylinder and a square mounting plate integrally formed with the cylinder, and the mounting plate is fixed on the Ultrasonic flow meter.

Further, the mounting plate is symmetrically provided with connecting holes, and the mounting plate is fixed to the ultrasonic flow meter through the connecting holes through screws.

Further, a sealing hole is formed through the base, and a sealant is provided at the end of the sealing hole close to the piezoelectric element.

Further, the sealing hole is a stepped hole, the diameter of one end of the stepped hole close to the housing is smaller than the diameter of the other end, and the sealant is provided at the small diameter section of the stepped hole close to the end of the housing.

Further, the cylinder is provided with external threads, and the mounting hole is provided with internal threads matching the external threads.

Further, a sealing groove is provided on the base, and a sealing ring is installed in the sealing groove.

Further, the sealing groove is arranged between the external thread on the cylinder and the piezoelectric element.

Further, the acoustic matching layer is made of glass, epoxy resin or ceramics, the acoustic impedance of the acoustic matching layer is 0.1-0.8 MRayl, and the acoustic impedance of the shell is 1-8 MRayl; the shell The body is made of metal.

Further, the end of the piezoelectric element close to the sealant is connected with a connection line, and the connection line is sealed with the sealant and extends out of the sealing hole.

Further, the thickness of the acoustic matching layer is 2-8mm; the outer diameter of the shell is 15-21mm.

Beneficial effects of the present invention: the base of the present invention includes a cylinder and a square mounting plate integrally formed with the cylinder. Through the above base structure, the mounting plate is fixed to the ultrasonic flowmeter by screws. Compared with the existing The base and the ultrasonic flowmeter are directly threaded, which reduces the length of the base, further reduces the occupied space of the transducer, and facilitates installation.

Description of drawings

Fig. 1 is the sectional view of transducer described in the present invention;

Fig. 2 is a sectional view of the casing of the present invention;

Fig. 3 is a schematic structural view of the base of the present invention.

In the picture:

1. Shell; 11. Mounting hole; 2. Acoustic matching layer; 3. Piezoelectric element; 4. Base; 41. Cylinder; 411. Sealing groove; 42. Mounting plate; 421. Connection hole; 43. Sealing hole ; 5, sealant; 6, sealing ring.

detailed description

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods.

As shown in Figures 1 to 3, this embodiment provides a transducer for an ultrasonic flowmeter, which includes a housing 1 provided with a mounting hole 11, an acoustic matching layer 2 and a pressure sensor installed in the mounting hole 11 in sequence. The electric element 3, and the base 4 which is sealedly connected with the housing 1 and one end is pressed against the piezoelectric element 3, the piezoelectric element 3 and the acoustic matching layer 2 are sealed between the housing 1 and the base 4; the base 4 includes a cylinder 41 and a square mounting plate 42 integrally formed with the cylinder 41, and the mounting plate 42 is fixed to the ultrasonic flowmeter by screws. In this embodiment, through the above-mentioned base structure, the mounting plate is fixed to the ultrasonic flowmeter by screws. Compared with the existing screw connection between the base and the ultrasonic flowmeter, the length of the base is reduced, and the size of the transducer is further reduced. Occupies space and is easy to install.

Specifically, in this embodiment, the mounting plate 42 is symmetrically provided with connecting holes 421 , and the transducer described in this embodiment is installed on the casing of the ultrasonic flowmeter through the connecting holes 421 and screws.

The material of the acoustic matching layer 2 described in this embodiment is glass, epoxy resin or ceramics, the piezoelectric element 3 has the bidirectionality of transmitting and receiving, and in actual use, two relatively distributed transducers are arranged on the ultrasonic flowmeter. In actual operation, the generating end of one of the transducers transmits the characteristic signal into the fluid through the double matching layer structure formed by the acoustic matching layer 2 and the housing 1 until it is received by the receiving end of the other transducer. The characteristic signal will reach the piezoelectric element 3 from the housing 1 and the acoustic matching layer 2 in sequence. The acoustic impedance rate of the acoustic matching layer 2 described in this embodiment is between 0.1-0.8 MRayl, and the acoustic impedance rate of the housing 1 is between 1-8 MRayl, and the acoustic impedance rate can be measured through the above-mentioned acoustic matching layer 2 and the housing 1 Fluids below 1MRayl. Determine the thickness of the acoustic matching layer 2 according to the required acoustic impedance of the acoustic matching layer 2, the thickness of the acoustic matching layer 2 in this embodiment is 2-8mm; the outer diameter of the housing 1 is also according to the needs The acoustic impedance rate is determined, and the outer diameter of the housing 1 in this embodiment is 15-21mm.

Acoustic impedance matching of a single matching layer is cumbersome and needs to be designed with composite materials. Only the characteristic acoustic impedance value can be used to send and receive characteristic signals. In addition, composite material designs that meet the above conditions are not easy to obtain. The double matching layer structure formed by the acoustic matching layer 2 and the casing 1 described in this embodiment improves the conversion efficiency of the piezoelectric element 4 and ensures a better sound wave transmission coefficient.

As shown in FIG. 3 , in this embodiment, a sealing hole 43 is formed through the base 4 , and a sealant 5 is provided at an end of the sealing hole 43 close to the piezoelectric element 3 . A sealed connection between the sealing hole 43 and the contact point between the piezoelectric element 3 is ensured by the sealant 5 .

The sealing hole 43 is a stepped hole, the diameter of one end of the stepped hole close to the housing 1 is smaller than the diameter of the other end, and the sealant 5 is provided on the small diameter section of the stepped hole close to the end of the housing 1 .

The cylinder 41 is provided with an external thread, and the mounting hole 11 is provided with an internal thread matching the external thread 41 . The base 4 and the housing 1 are connected through the matching connection between the external thread on the cylinder 41 and the internal thread in the mounting hole 11 . Wherein, both the internal thread and the external thread are fine-pitch threads, which can effectively prevent thread loosening after long-term use. In order to ensure the sealing effect between the base 4 and the housing 1 , the wall surface of the installation hole 11 has a relatively high surface finish, specifically reaching 3.2 μm or higher. The surface roughness of the wall surface of the installation hole 11 in this embodiment is 3.2 μm.

In order to meet the needs of actual use, the housing 1 described in this embodiment is required to be a metal shell, and the wall thickness of the housing 1 and the internal thread on the mounting hole 11 can meet the requirements under the environment below 10MPa and -40°C to +120°C use.

As shown in Figures 2 and 3, the base 4 is provided with a sealing groove 411, the sealing groove 411 is arranged between the external thread on the cylinder 41 and the piezoelectric element 3, and the sealing ring 6 is installed in the sealing groove 411 , a sealed connection between the casing 1 and the base 4 is realized. The acoustic matching layer 2 and the piezoelectric element 3 are sealed between the base 4 and the housing 1 through the sealing ring 6 and the sealant 5 . The sealing ring 6 in this embodiment is an O-ring.

In this embodiment, one end of the piezoelectric element 3 close to the sealant 5 is connected with a connection wire 7 , and the other end of the connection wire 7 passes through the sealant 5 and extends out of the sealing hole 43 . The piezoelectric element 3 is connected to the ultrasonic flowmeter through a connection line 7 to realize signal transmission between the two.

When making the transducer described in this embodiment, first put the acoustic matching layer 2 and the piezoelectric element 3 into the installation hole 11 of the housing 1 in sequence, then install the sealing ring 6 in the sealing groove 411, and then place the The base 4 with the sealing ring 6 installed is installed on the housing 1 through the cooperation of internal and external threads, and then the base 4 is filled with glue, and the sealant 5 is filled into the sealing hole 43 to form a glue seal area, which is completed Fabrication of transducers. The finished transducer is fixed on the shell of the ultrasonic flowmeter through the connecting hole 421 through the screw.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. a kind of ultrasonic flowmeter transducer, it is characterised in that including the housing (1) provided with mounting hole (11), install successively Supported in acoustic matching layer (2) and piezoelectric element (3) in the mounting hole (11), and with housing (1) sealed connection and one end The base (4) of piezoelectric element (3) is pressed on, the piezoelectric element (3) and acoustic matching layer (2) sealing are located at housing (1) and base (4) between；The base (4) include cylinder (41) and with the integrally formed square installing plate (42) of the cylinder (41), institute State installing plate (42) and ultrasonic flowmeter is fixed on by screw.

2. ultrasonic flowmeter transducer according to claim 1, it is characterised in that symmetrically set on the installing plate (42) There is connecting hole (421), the installing plate (42) is fixed on ultrasonic flowmeter by screw through connecting hole.

3. ultrasonic flowmeter transducer according to claim 2, it is characterised in that run through on the base (4) and be provided with Sealing hole (43), the sealing hole (43) are provided with fluid sealant (5) close to one end of piezoelectric element (3).

4. ultrasonic flowmeter transducer according to claim 3, it is characterised in that the sealing hole (43) is ladder Hole, diameter of the shoulder hole close to housing (1) one end are less than the diameter of the other end, and the fluid sealant (5) is located at the ladder The path section in hole is close to one end of housing (1).

5. ultrasonic flowmeter transducer according to claim 4, it is characterised in that the cylinder (41) is provided with outer spiral shell Line, the mounting hole (11) is interior to be provided with the internal thread being adapted with external screw thread.

6. ultrasonic flowmeter transducer according to claim 5, it is characterised in that the base (4) is provided with sealing Groove (411), the seal groove (411) is interior to be provided with sealing ring (6).

7. ultrasonic flowmeter transducer according to claim 6, it is characterised in that the seal groove (411) is located at post Between external screw thread and piezoelectric element (3) on body (41).

8. ultrasonic flowmeter transducer according to claim 7, it is characterised in that the acoustic matching layer (2) is by glass Glass, epoxy resin or ceramics are made, and the specific acoustic impedance of the acoustic matching layer (2) is 0.1-0.8MRayl, the housing (1) Specific acoustic impedance is 1-8MRayl, and the housing (1) is made of metal.

9. ultrasonic flowmeter transducer according to claim 8, it is characterised in that the piezoelectric element (3) is close to close One end of sealing (5) is connected with connecting line (7), and the connecting line (7) is through fluid sealant (5) and stretches out sealing hole (43).

10. ultrasonic flowmeter transducer according to claim 9, it is characterised in that the thickness of the acoustic matching layer (2) Spend for 2-8mm, the external diameter of the housing (1) is 15-21mm.