SU1665327A1 - Metal locator - Google Patents

Abstract

The invention relates to instrumentation engineering and can be used to detect hidden metallic masses, pipelines, cables, and the like. electromagnetic methods. The purpose of the invention is to increase the capture bandwidth of the metal detector without reducing its noise immunity. The metal detector contains a generator, an excitation frame connected to it, two identical differential-connected receiving frames, a signal receiver connected to the receiver frames and a signal receiver, and a signaling node connected to the receiver. The metal detector is also provided with an additional pair of identical differentially included receiving frames. Both pairs of receiving frames are installed symmetrically with respect to the exciting frame. A second signal receiver is connected to the second pair of receiving frames and the generator, and the signaling node is connected to both receivers via the OR circuit. 2 Il.

Description

one

(21) 3705417/25 (22) 06.01.84 (46) 07.23.91. Bul №27

(71) Special design bureau Project neftegazspetsmontazh

(72) Yu.M.Mamontov, V.R.Andrianov, V.Yu. Danilov, I.G.Romanov and B.S. Chubarov

(53) 550.83 (088.8)

(56) 1. Bakhmutsky V.F., Zuenko G.I. Induction cable detectors. M .: Svyi, 1970, pp.75-78.

2. USSR author's certificate No. 1061089. cl. G 01 V3 / 11, 1982.

(54) METAL DETECTOR

(57) The invention relates to instrumentation engineering and can be used to detect hidden metallic masses, pipelines, cables, and the like. electromagnetic methods. The purpose of the invention is to increase the capture bandwidth of the metal detector without reducing its noise immunity. The metal detector contains a generator, a driving frame connected to it, two identical differential-connected receiving frames, a signal receiver connected to the receiving frames and a generator and a signaling receiver connected to the receiver. The metal detector is also provided with an additional pair of identical differentially included receiving frames. Both pairs of receiving frames are installed symmetrically with respect to the exciting frame. A second signal receiver is connected to the second pair of receiving frames and the generator, and the signaling node is connected to both receivers via the OR circuit. 2 Il.

The invention relates to a technique for detecting metallic objects, such as pipelines, cables.

Known metal detector containing two differential included receiving frame located on both sides of the exciting frame 1.

The disadvantage of this device is low noise immunity.

The closest in technical essence to the invention is a metal detector containing a signaling unit, a generator, the output of which is connected to the excitation frame, the first and second identical horizontal receiving frames arranged coaxially, connected differentially to the receiver input, while the receiver contains serially connected balancing unit, block

compensation, the reference input of which is connected to the output of the generator, a selective amplifier and a signal processing unit, the exciting frame located in a plane passing through the axis of the first and second receiving frames, symmetrically with respect to them 2J.

A disadvantage of the known device is the impossibility of increasing the capture bandwidth without reducing the noise immunity.

The purpose of the invention is to increase the capture bandwidth without compromising noise immunity.

This goal is achieved by the fact that a metal detector. containing a signaling unit, a generator, the output of which is connected to the excitation frame, the first and second identical horizontal receiving frames

ate with

hO x |

coaxially arranged ki, differentially connected to the input of the first receiver, the first receiver comprising a balancing unit connected in series, a compensation unit whose reference input is connected to the generator output, a selective amplifier and a signal processing unit, the exciting frame located in the plane passing through the axis of the first and second receiving frames, symmetrically with respect to them, also contains the third and fourth receiving frames, identical to the first and second receiving frames, located simme Initially, with respect to the axis I excite: a common frame, an OR circuit and a second receiver, identical to the first receiver, the signal differential inputs of which are connected to the third and fourth receiving frames, the reference input is connected to the output of the generator, and the output is connected to the second input the OR circuit, the first input of which is connected to the output of the first receiver, and the output to the input of the alarm unit.

Figure 1 shows the metal detector; Fig. 2 is a spatial scheme for the arrangement of the excitation and reception frames;

The device contains a generator 1, exciting frame 2, the first, second, third and fourth receiving frames 3-6, the first and second receivers 7 and 8, the circuit OR 9 and the block 10 alarm. The first receiver 7 comprises a balancing unit 11, a block

12 compensation selective amplifier

13 and block 14 signal processing. The second receiver 8 is similar to the first receiver 7

The first and second receiving frames 3 and 4 and the third and fourth frames 5 and 6 are located horizontally, pairwise coaxially and symmetrically with respect to the exciting frame 2 at a distance from it, connected in pairs with the exciting frame 2 using first and second rods 15 and 16 .

The metal detector works as follows.

The generator 1 creates in the exciting frame 2 a sinusoidal current of a given frequency, creating in the area under study a variable primary electromagnetic field (EMI), the first and second channels formed by the first and second receiving frames 3 and 4 and the first receiver 7, as well as the third and fourth receiving frames 5 and 6 and the second receiver 8, work the same. In the absence of a metal object, the output signal of the compensation blocks 12 is zero due to the geometric and electrical compensation of the signal. If there is a metal object in the detection area, the secondary EMF induces an emf in pairs of receiving frames: first and second 3 and 4, third and fourth 5 and 6, which depends on the distance to the metal object. The signals from the outputs of the compensation unit 12 through the selective amplifiers 13 and the signal processing units 14 are fed to the first and second inputs of the OR circuit 9, which sends a detection signal to the input of the signaling unit 10.

The invention makes it possible to increase the capture bandwidth without compromising noise immunity by using two symmetric detection channels, where the additional second detection channel is formed by two additional receiving frames, a second receiver, and also an OR circuit used to sum the signals of both channels.

Claims (1)

A metal detector comprising a signaling unit, a generator, the output of which is connected to the excitation frame, the first and second identical horizontal receiving frames arranged coaxially, connected differentially to the input of the first receiver, the first receiver containing a series-connected balancing unit, a compensation unit, a reference input which is connected to the output of the generator, a selective amplifier and a signal processing unit, the exciting frame being located in the plane passing through the axis of the first and second receiving frames is symmetrical with respect to them, characterized in that, in order to increase the capture bandwidth without reducing the noise immunity. The metal detector contains the third and fourth receiving frames, identical to the first and second receiving frames, located symmetrically with respect to the axis of the exciting frame, the OR circuit and the second receiver, identical to the first receiver, the signal differential inputs of which are connected to the third and fourth receiving frames, the reference input is connected with the output of the generator, and the output with the second input of the OR circuit, the first input of which is connected to the output of the first receiver, and the output to the input of the alarm unit. Editor O. Yurkovetskaya Tehred M. Morgental Order 2390 Circulation 342Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow. Zh-35, Raushska nab., 4/5 Production and publishing combine Patent, Uzhgorod, Gagarin str. 101 Ft g Proofreader M Kucher VA