CN2225025Y

CN2225025Y - Capacitance level meter

Info

Publication number: CN2225025Y
Application number: CN 95201496
Authority: CN
Inventors: 王枫; 赵文虎; 夏登海; 陈永泰
Original assignee: KELI TECHNOLOGY DEVELOPMENT Co WUHAN
Current assignee: KELI TECHNOLOGY DEVELOPMENT Co WUHAN
Priority date: 1995-02-27
Filing date: 1995-02-27
Publication date: 1996-04-17
Anticipated expiration: 2005-02-27

Abstract

The utility model relates to a capacitance level meter which is a device that uses the capacitance change of a capacitor in the medium to detect the height position of the medium in a storage bin. The electrode of the utility model is composed of a segmenting and folding metal pipe or a steel cable of which the outer part is wrapped with an insulating protective layer. The electrode is connected with a preamplifier by a leading wire. The inner walls of the upper part and the lower part of the storage bin are respectively provided with an upper and a lower level switches. The utility model can effectively eliminate the influence of the temperature and the humidity for the measuring accuracy, and thus, the measuring accuracy is improved. The utility model has the advantages of simple structure, convenient production, installation and debugging, and stable and reliable operation, which can be served as the detection device of sealed bins in the fields of the electric power, the metallurgy, the chemical industry, the building material, the food, etc.

Description

The condenser type level-sensing device

The condenser type level-sensing device relates to a kind of liquid or mobile solid-state material of using and is in that the changes in capacitance that causes capacitor in the electric field is measured or the instrument of indicating liquid liquid level or the residing height and position of solid-state material charge level.

The principle of condenser type level-sensing device and technical scheme thereof proposed as far back as the publication of U.S.'s publication in 1945, but owing to be subjected to multifactorial influences such as temperature in the feed bin, pressure, density, cause these technical schemes also to have many defectives, to await people perfect further.Recently, " level indicator " (application number: 88108312.7 that the applicant retrieved, publication number CN1042985A) and " level-sensing device " (application number: 91108963.2, publication number CN1059597A) all improves design at the existing shortcoming of its type product in early stage, learn from disclosed data, these all are the schemes that certain technical merit and using value are arranged, and they can carry out continuous coverage; Give meter and may overcome the influence that material fluctuation and change etc. causes in material temperature, humidity, variable density and the storehouse; And it is adjusted automatically; And be suitable for measurement to the viscous mass material level; Measuring accuracy is higher; Easy to use.But also there is following problem in the practice: the first, be difficult on complex structure, the technology realize.In order to bear corresponding gravity, the used cable of electrode with the wire rope be surrounded by three layers of sheath on skeleton, the wire rope, their periphery of two-layer screen layer disposes six roots of sensation heart yearn, every heart yearn is added with three layers of screen layer and four layers of sheath again.This shows the realization of kind electrode and with it section of being divided into, make multi-electrode, its difficulty is difficult to overcome.The second, the temperature coefficient of each covering is different, and expansion coefficient is differed, and cause interlayer to produce relative displacement and malformation, thereby influenced measuring accuracy, and to not working.The 3rd, the stuff level switch mis-arrange, last switch is positioned at the top in storehouse, following switch is positioned at the bottom in storehouse, has only when the material that injects rises to switch, and sensor just output signal represents that feed bin is fully loaded, and it is topped to descend switch always to be injected into material, therefore, is in normal phase duty.In fact the infusion in the feed bin, mostly operation in 1/4th to 3/4ths scope of feed bin height.So the last switch of such scheme and following switch are in respectively under normally closed and the normally open, therefore, this design is irrational.

The design the purpose of this utility model is to provide the electric capacity continous way level-sensing device that can check liquid in all kinds of gas-tight silos or flowing solid material height for industries such as electric power, metallurgy, chemical industry, light industry, food.It should be able to satisfy the requirement of enforcement reasonable in design, simple in structure, easy, stable and reliable operation.

Claimed technical scheme is as follows:

The condenser type level-sensing device by feed bin, electrode, prime amplifier, go up stuff level switch, parts such as stuff level switch and single-chip microcomputer etc. are formed down.Main design concept is such: electrode adopts the collapsible metal tube of segmentation or a wire rope that is wrapped with one deck insulating protective layer to constitute, and segmentation metal tube electrode or wire rope electrode are connected with a prime amplifier by lead-in wire.Stuff level switch and following stuff level switch are being housed respectively on the inwall of the above and below of feed bin.Collapsible segmentation metal tube is an one by universal structure, and the sagging naturally extension line of going up stuff level switch and following stuff level switch is connected with prime amplifier respectively by bin wall.When adding certain material, constituted two utmost points between electrode and the feed bin, formed electric field between them when electrifying electrodes and in feed bin.If the distance of the useful area of two electrode slices and two pole pieces one regularly, then electric capacity C depends on the specific inductive capacity and the injection rate IR thereof of institute's injected material, if can the factors such as temperature, humidity, density and pressure of the infusion that influences electric capacity be compensated or eliminate, then electric capacity is only relevant with the height of infusion, i.e. the variation of electric capacity has reflected the variation of infusion height.Therefore, by electrode measured electric capacity signal is transported to single-chip microcomputer after the prime amplifier computing and handle, thereby draw the height and position of institute's infusion in the feed bin.

Below by embodiment, the technical scheme of condenser type level-sensing device is further described.

Fig. 1 is a condenser type level-sensing device structure block diagram, wherein: 1---feed bin, can make by metal or concrete; 2---electrode, can constitute by segmentation folding metal tube or a wire rope, optional 2～6 joints, every joint is that the wire rope that 0.5～1.5 meter 1/4th to one and 1/2nd inches weldless steel tube or overall diameter are 6～16 millimeters constitutes, as work under the normal temperature, can select tygon, polypropylene insulating protective layer for use as wire rope; As be operated in when being higher than 100 ℃, then can select for use teflon as insulating protective layer; 3---ring flange is used for fixing electrode; 4---prime amplifier, can select DC for use---06 prime amplifier, the master oscillator frequenc of this amplifier is 32KHz, has adopted the non-inductance electric heating utmost point, and is provided with temperature-compensation circuit; 5---on line; 6,7---upper and lower stuff level switch electrode, constitute by DC-06 moulding mixture bit switch, they are installed in respectively on the inwall of the feed bin at 1/4th and 3/4ths places, feed bin bottom, are used for material level calibration and corrective action; 8,9---ring flange; 10,11---prime amplifier, still select the DC-06 prime amplifier for use; 12---single-chip microcomputer; 13,14---cable.

Fig. 2 is the collapsible metal tube electrode structure of a condenser type level-sensing device segmentation synoptic diagram, wherein: 1---and the metal tube electrode; 2---Hook's coupling spare; 3---electrode contact; 4---the preceding amplifier of wanting.

Fig. 3 is a condenser type level-sensing device steel wire rope type electrode structure synoptic diagram, wherein: 1---and wire rope; 2---anchor clamps; 3---ring flange; 4---weight its role is to prevent that material influences electrode and the perpendicular state of level in the feed bin; 5---prime amplifier.

Fig. 2 and Fig. 3 have described two kinds of embodiment that electrode constitutes in the utility model respectively

The utility model is compared with background technology has following beneficial effect:

(1) simple in structure, be convenient to produce, install and debugging.

(2) adopted metal tube or the wire rope of one deck insulating protective layer is only arranged, and upper and lower stuff level switch positioning of electrode is accurate, makes temperature, humidity less, improved precision and the reliability thereof measured the influence of measuring.

Claims

1, a kind of condenser type level-sensing device is made up of feed bin, electrode, stuff level switch and prime amplifier etc., it is characterized in that:

A, electrode are made of folding metal tube of segmentation or the wire rope that is wrapped with one deck insulating protective layer,

B, metal tube or wire rope are connected with prime amplifier,

C, on the inwall of the upper and lower of feed bin, stuff level switch and following stuff level switch are housed respectively.

2,, it is characterized in that folding each section metal tube of segmentation is 1/4th to one and 1/2nd inches weldless steel tube and is one by universal knot connecting piece structure according to the described condenser type level-sensing device of claim 1.

3, according to the described condenser type level-sensing device of claim 1, the overall diameter that it is characterized in that wire rope is 6～16 millimeters, and it is wrapped with the insulating protective layer of tygon, polypropylene or teflon, and the upper and lower end of wire rope links to each other with ring flange, weight respectively.

4,, it is characterized in that the extension line of stuff level switch and following stuff level switch is connected with prime amplifier respectively through bin wall according to the described condenser type level-sensing device of claim 1.

5, according to claim 1 or 4 described condenser type level-sensing devices, it is characterized in that prime amplifier is made of the DC-06 prime amplifier.

6, according to the described condenser type level-sensing device of claim 1, the resistance value at the head and the tail two ends of its feature segmentation folded metal pipe or wire rope electrode is less than 1 ohm.