WO1999063305A2

WO1999063305A2 - Electronic spirit level for measurement of inclination

Info

Publication number: WO1999063305A2
Application number: PCT/SI1999/000013
Authority: WO
Inventors: Boris GERŠAK
Original assignee: Gersak Boris
Priority date: 1998-06-01
Filing date: 1999-05-18
Publication date: 1999-12-09
Also published as: SI9800162A; WO1999063305A3; AU3739499A

Abstract

Electronic spirit level for measurement of inclination from 0 to 360 degrees. In a circular tube being bent into a round ring and only partially filled with electrically conducting spirit along the entire perimeter there is placed a resistor in form of wire with equally varying sectional area. Therefore the resistance of the system depends upon the position of the air bubble. The resistance is measured and calculated into angular degrees and displayed upon the screen. By that the housing can be more or less filled with spirit. At the outer side can be tightly one beside the other placed coils, where each of coils is separately connected to the measuring instrument. When upon the wire in the inside the alternating electric voltage is connected, in all coils electric voltage shall be induced. There where the air bubble is placed also the induced voltage in the coils is different. By successive measurements in all coils it can be precisely ascertained where at the moment the air bubble is situated. The air bubble and the inner wire can be substituted by a small metallic ball.

Description

ELECTRONIC SPIRIT LEVEL FOR MEASUREMENT OF INCLINATION

The scope of the invention is an electronic spirit level for measurement of inclination from 0 to 360 degrees. It is purposed for general use in construction, engineering, households etc. and for special purposes, where high accuracy is required as in laboratories, military equipment etc.

This invention is solving three problems: Problem 1

The accuracy of measurement of inclination angle should depend upon visual ability of the particular user.

Problem 2

Measurement of all inclination angles from 0 to 360 degrees should be possible.

Problem 3

In certain domains of use very accurate measurement of inclination with regard to the direction of gravitation is required.

The hitherto known solutions for the listed problems.

Known are the following letters of patent dealing with similar problems and thus: US,A,1 826 731(CHATHAM), 13. 10. 1931. The housing has a form of transparent cylindrical vessel which is to its half filled with spirit and above it there is an air bubble. The scale for measurement of degrees is impressed upon the transparent vessel. The level of liquid upon the scale displays the inclination in degrees.

US, A, 2287 863 (BUCKLEY), 30. 6. 1942. The housing has a form of circular transparent pipe being bent in a round circle. It is filled with spirit, where upon the top is a little air bubble. The degree scale is impressed upon the housing. The air bubble upon the scale displays the inclination in degrees.

DE, C, 878 726 (KLEINHANS), 18. 9. 1952. The housing in form of a transparent pipe being bent in a round circle, to its half filled with spirit. The degree scale is impressed upon the housing. The level of liquid upon the scale displays the inclination in degrees.

Nevertheless no hitherto known design includes the solution for all the three problems stated above simultaneously. The accuracy of reading is depending of the users visual ability. High accuracy is not guaranteed.

Solving of the problems with this invention

Solving of the problems 1, 2 and 3:

The measurement of inclination angle is performed with aid of an electronic instrument. Very accurate value is displayed upon the screen in form of digits. The solution is possible in four manners. 1. 1 The housing formed as a circular tube curved in a circular ring is partially filled with electrically conducting spirit. Within the housing along the whole perimeter a resistance in form of wire is placed, evenly changing its sectional area. To the wire electric voltage is connected and with corresponding instrument the actual resistance of this system can be measured. Through one part of its path the current is flowing through the electrically conducting spirit, but where an air bubble is located only through the wire. Because the sectional area of the wire is changing along the length, the resistance of the part of wire being within the air bubble depends upon the place where the air bubble is situated. The resistance of the whole system is a sum of both resistances. The value of the entire system resistance can be accurately measured and displayed upon the screen. By that the housing in forni of a circular ring can be more or less filled with spirit, respectively the air bubble can be short including only some angular degrees or long to include 180 angular degrees. The housing can also be formed as a circular cylindrical vessel, being to its half filled with spirit.

1. 2 The housing formed in form of a circular tube, curved in a ring is partially filled with electrically conducting spirit. In the housing along the whole perimeter a resistance in forni of wire is placed, having along its whole length an equal sectional area.

At the outer side upon the housing the coils are placed. The whole ring is covered with coils being placed tightly one beside the other or being partially covering each other. Each coil is separately connected to the measuring instrument. When upon the wire in the inside the alternating electric voltage is connected, in all coils the alternating voltage shall be induced. Because the conditions in the part of the ring, where there is an air bubble are different as elsewhere, also the induced voltage in the coils of this area is different. By successive measurements in all coils, it can be precisely ascertained where at the moment the air bubble is situated. With it the electrical properties of all coils must be exactly known. Also in this case the air bubble can be either short or long and the hosing is formed as a ring or as cylindrical vessel being to its half filled with spirit.

1. 3 The housing in form of circular tube, curved in a round ring is partially filled with electrically conducting spirit. In the housing along the whole perimeter a resistance in form of wire is placed, where the section area is evenly changing. From the outer side upon the housing the coils are placed. By this the induced voltage in the outer coils is changing simultaneously also along the length of the bubble. At one part of the bubble the induced voltage is higher in order to than be evenly diminished along the whole length of the bubble towards the other part. With both kinds of data the beginning and the end of the bubble can be determined more easily as only from one kind of data. Thus the measurement is more accurate.

1. 4 In the housing, formed by a circular tube curved in a round ring a small metallic ferrite ball is placed. The diameter of the ball is slightly smaller as the diameter of the tube, thus the ball can freely roll hither and thither. Upon the outer part of the housing the coils are placed. When through every coil high-frequency electric current is passed, with successive measurements in the coils it can be exactly determined where at the moment the ball is situated. With it the electric properties of all coils must be exactly known. The housing can also be filled with spirit.

The housing formed as a round tube, curved in a round ring, containing a small metallic ball is filled with electrically conducting spirit. When alternating electric voltage is connected to the spirit in all coils, voltage is induced. Because the conditions at the part of the ring where is the metallic ball differ from those elsewhere, also the induced voltage in the coils of this area will differ. By measurement of induced voltage in this area, the vertical middle axle of the ball can be determined and with it the angle of inclination.

To the housing formed of the circular tube, curved in a circular ring, where there is a metallic ball, is of metal or other electrically conducting material. The inside of the housing is without spirit. When alternating electric voltage is connected to the housing in all coils electric voltage shall be induced . Because the conditions in the part of the circular ring, where is the small metallic ball differ from the conditions elsewhere, also the induced voltage in the coils in this area will differ.

An advantage of all cited solutions is, besides of the accurate measurement and reading, not depending on the visual ability of the user in this that they enable the measurements of inclination from 0 to 360 degrees,.

The accuracy of the measurement itself can be very high. It depends of the quality for manufacturing of the resistance wire, the housing and of the small ball and the number of coils and of accuracy for calibration of the coils. A disadvantage, before of all, is that the induced voltage in each coil must be measured separately. It means that so many switchings are required as there is the number of coils. But the measurement is more accurate if there are more coils and the more they are overlapping each other.

Designing solutions

The designing solutions are shown upon seven cases of execution.

The execution case No. 1 is shown upon the Figure 1

In the outer housing (101) being upon the plain (104) of which the inclination must be measured, there is a built-in housing (1) in form of a round tube bent in round circle. The housing (1) is partially filled with electrically conducting spirit (2). In the housing along the whole perimeter resistance in form of wire (4) is placed, where evenly the sectional area changes. When to the wire electric voltage is applied, the resistance of this system at this moment can be measured. A part of its path the current passes through electrically conducting spirit, and where there is an air bubble (3) only through the wire. Because of the sectional area of the wire changes with length, the resistance of that part of wire being "dry" in the air bubble depends upon the place of the air-bubble. The value of the resistance can be exactly measured with an instrument (103) in order to be calculated in angular degrees and in form of digits shown upon the screen (102).

The execution case No. 2 is shown upon the Figure 2

In the housing (7) there is an air bubble (3) so large that it fills the whole sectional area of the tube and in the length of the circumference may be up to 180 angular degrees. The wire is marked by (4), the filling spirit with (2), the voltage terminals with (5,6).

The execution case No. 3 is shown upon the Figure 3

The housing (8) is formed as cylindrical vessel being to its half filled with spirit (2), where over it there is an air bubble (3). The wire is marked with (4), voltage terminals with (5,6).

The execution case No. 4 is shown upon the Figures 4, 8 and 10

Figure 4 displays the housing (1) formed as a round tube, bent in a round circle, is partially filled with electrically conducting spirit (2). In the housing along the whole perimeter a resistance is placed in form of wire (4), having along its whole length equal or variable sectional area and voltage terminals (5,6) at the ends. On the outer side upon the housing the coils (9) are placed. Where the coils may be wound up around the housing or the coils can be placed besides the housing. The whole circle is covered with coils, being placed close one to the other or even partially covering each other. Every coil is separately connected to the measuring instrument. When alternating electric voltage is connected to the inside wire in all outer coils alternating electric voltage is induced. Because of the conditions on that part of the ring where is an air bubble are different as elsewhere, also the induced voltage in the coils within this area is different. By successive measurements in all coils it can be precisely ascertained where at the moment the air bubble is placed. With it the electric properties for all coils must be exactly known.

When the sectional area of the wire changes evenly, the induced alternating voltage in the outer coils will evenly change simultaneously along the air bubble length. At one part of the air bubble, the induced voltage is higher in order to be uniformly decreased to the other end. Of two kinds of data the beginning an the end of the air bubble can be more easily determined as only with one kind of data. The measurement is more accurate.

Figure 8 displays the results(16) of measurements of induced voltage in each particular coil along the perimeter of the tube are shown. The voltage is marked with (U), with (n) the successive number of coil. With (3) is marked the air bubble in the housing, with (4) the wire and with (L) the length of the bubble.

The induced voltage (U) is outside the air bubble (3) area equal in all coils. At the beginning of the air bubble it is changed and gradually increasing to its highest value. In the area of the air bubble the voltage in all coils is equal again and at the end of the bubble it is diminished to the value in the outside of the air bubble. With an interpolation of values of induced voltage calculation can be performed exactly, where there is the middle of the air bubble and with it the angle of inclination. The shown results are like this, when the wire (4) has equal sectional area along its whole length.

Figure 9 demonstrated is the lay out of the coils (9) placed tightly one beside the other, placed upon the housing (1). The air bubble is (3) and (4) is the wire in the inside of the housing.

Figure 10 displays the arrangement of the coils (9) partly covering each other upon the housing (1).

The air bubble is (3) and (4) is the wire in the inside of the housing.

The execution case No.5 is shown upon the Figure 5

In the housing (7) there is the spirit (2) and an air bubble (3) which can include an angle of 180 angular degrees. The wire (4) is in the housing and the coils (9) are placed on the outer side or upon the housing or they are besides the housing. The voltage terminals in of the wire are (5,6).

The execution case No. 6 is shown upon the Figure 6

In cylindrical housing (4) there is the spirit (2) and the air bubble (3) which may be extended to an angle of 180 angular degrees. The wire (4) has two terminals (5,6). The outer coils are (9). The coil are placed so that the axle of a coil is perpendicular to the tangent of the wire (4).

The execution case No. 7 is shown upon the Figure 7

In the housing (1), formed as a circular tube, bent in a round circle there a small metallic-ferrite ball (15) is placed. The rest of the inside of housing may be empty or filled with spirit (2). The diameter of the small ball can be slightly smaller as the inner diameter of the tube, so that the ball can freely roll hither and thither. At the outer side upon the housing the coils (9) are placed. When through each coil high-frequency electric current is passed, with the successive measurement in all coils, the position of the ball at this moment can be determined. With it the electric properties of all coils must be exactly known.

The housing (1), formed by the circular tube, curved in a circular ring, where a small metallic ball (15) is placed, is filled with electrically conducting spirit (2) having electric voltage terminals (5,6). When the alternating electric voltage is connected to the spirit, in the coils voltage shall be induced. Because the conditions at the part of the ring where there is the metallic ball differ from these elsewhere, also the induced voltage in this area is different.

The housing (1), formed by a circular tube, curved in a ring, where a small metallic ball (15) is placed, has terminals for electric voltage (5,6) and is made of a metal or another electrically conducting material. There is no spirit in the inside of the housing. When electric voltage is connected to the housing in all coils voltage shall be induced. Because the conditions at that part of the ring where is the small metallic ball are different as elsewhere, also the induced voltage in the coils in this area will be different.

Claims

Patent claims

1. Electronic spirit level for measurement of inclination from 0 to 360 degrees, having the form of circular ring bent round tube, only partially filled with spirit (2), characterized with it, that in the spirit (2) by which the housing(1) is partially filled is electrically conducting and in the housing (1) placed along its whole circumference there along the whole perimeter is placed a wire of which the cross section uniformously changes along its whole length and so a part of the wire (4) is not wetted with spirit (2) but it is conveyed through an air bubble (3) and the wire (4) has terminals (5,6) whereto the supply of electric current is connected and also a measuring instrument (103) and a screen (102) for monitoring of the angle in digital form.

2. Electronic spirit level, according to claim 1 , characterized with it, that the housing (7) is only filled to its half with the electrically conducting spirit (2).

3. Electronic spirit level, according to claim 1 , characterized with it, that the housing (8) in form of cylindrical vessel is only partially or to its half filled with electrically conducting spirit (2).

4. Electronic spirit level, according to claim 1 , characterized with it that the housing (1) is made of a tube with so small section area that the air bubble (3) completely fills the section area of the tube.

5. Electronic spirit level, according to claim 1 , characterized with it that along the outer perimeter of the housing (1) there are tightly one beside the other placed mutually electrically separated coils (9), where in each of the coils the induced voltage (16) must be separately measured.

6. Electronic spirit level, according to claim 5, characterized with it that the wire (4) has an uniform sectional area.

7. Electronic spirit level, according to claim 5, characterized with it that in the inside of the housing there is only a small metallic ball (15).

8. Electronic spirit level, according to claim 7, characterized with it that in the inside of the housing (1) there also is the spirit (2).

9. Electronic spirit level, according to claim 5, characterized with it that the coils (9) are slightly overlapping each other.

10. Electronic spirit level, according to claim 4, characterized with it that in the air bubble (3) there is the air with increased pressure.

11. Electronic spirit level, according to claim 8, characterized with it that the spirit (2) is electrically conducting, and having terminals for electric voltage (5,6).

12. Electronic spirit level, according to claim 7, characterized with it, that the housing (1) is made of metal or another electrically conducting material and having the voltage terminals (5,6).

13. Electronic spirit level, according to claim 1 , characterized with it, that he coils (9) are placed so that the axle of the coil is perpendicular to the tangent of the wire (4).