RU2338157C1 - Magnet compass - Google Patents

Abstract

FIELD: physics, measurement.

SUBSTANCE: invention concerns navigation instrument industry and can be applied in visual and remote magnet compasses for vessels. Object of invention is compass including sensitive magnet element, binnacle and quarter deviation compensator in the form of flat soft magnetic steel plate. Plate sets are fixed on binnacle at the planes parallel to binnacle base, symmetric to lengthwise symmetry plane of binnacle. Plate sets are cross-shaped and include rectangle parts radial and tangential to binnacle. Symmetry axes of radial and tangential set parts are perpendicular. Symmetry axis of radial part is perpendicular to lengthwise symmetry plane of binnacle and passes through vertical symmetry axis of binnacle. Length to width ratios of radial and tangential set parts are equal. Radial and tangential part length ratios defined by inequation R²(R²+l²)^3/2≤(R²+2l₁ ²)(R²+l₁ ²)^3/2, where R is distance between vertical symmetry axis of binnacle and vertical symmetry axis of plate set, l is a half of radial part length in a plate set; l₁ is a half of tangential part length in a plate set.

EFFECT: reduced heading indication error.

5 dwg

Description

The present invention relates to the field of navigation instrumentation and can be used in visual and remote magnetic compasses for ships and ships having a magnetic sensor system in the form of a system of arrows or a monolithic ring magnet, and contains a non-induction quarter-deviation compensator that increases the coefficient λ characterizing magnetic conditions compass work on a ship.

The known magnetic compass described in the book “Deviation of the magnetic compass” (V.P. Kozhukhov, V.V. Voronov, V.V. Grigoriev, L .: Sea transport, 1960, pp. 198-199, Fig. 69 pg. 207-209).

The compass contains a magnetic sensing element, a binnacle case. In the upper part of the compass binnacle, to the right and left of its longitudinal plane of OX symmetry along the tangent to the binnacle are longitudinal bars of soft (magnetically soft) iron forming a quarter deviation compensator. The bars are installed parallel to the longitudinal plane OX (Fig. 69).

The main disadvantages of the compass are

1. Longitudinal bars of soft iron (see pages 207-209) reduce the total coefficient λ, which characterizes the magnetic conditions at the location of the compass

due to the combined influence of ship's soft iron - coefficient λ ₀ and bars of the compensator of the quarter deviation - coefficient λ ₁ , with λ <λ ₀ , since λ ₁ <1.

2. The bars of the compensator of the quarter deviation located on the binnacle of the compass near its magnetic sensitive element, in addition to magnetization due to the magnetic field of the Earth, are additionally magnetized by the magnetic field of the magnetic sensitive element of the compass and, in turn, act on the magnetic sensitive element, causing a course error - deviation from induction (see p. 210-215, Fig. 76).

Magnetic compasses are known containing a magnetic sensitive element — a card (placed in a standard compass pot), binnacle, a quarter deviation compensator in the form of a set of longitudinal bars of soft magnetic iron and transversely mounted induction plates made of soft iron and placed inside the binnacle under the compass kettle. Induction plates provide the destruction of deviation from induction. Compasses are discussed in the book “Deviation of a Magnetic Compass,” pp. 215-221.

The disadvantages of such compasses are

1. A decrease in the coefficient λ due to the use of a quarter-deviation compensator in the form of sets of longitudinal bars located parallel to the longitudinal axis of symmetry of the compass.

2. The complexity of the work to destroy the deviation from induction using induction plates, the implementation of which requires a lot of skill. The works include the following:

- dismantling the compass (or its upper part) from its regular position on the ship (ship) and placing it on a special turning base on the shore;

- sequential (phased) performance of special work and calculations for the selection of bars of the compensator of the quarter deviation of appropriate sizes and their installation on the compass along with induction plates;

- moving the compass (or its upper part), with the bars and induction plates fixed, onto the ship (ship) and installing it in a regular place (see pages 217-221).

Known magnetic compasses equipped with non-induction compensators of the quarter deviation, considered in the book "Deviation of the magnetic compass", pp. 212-225. Such a compass contains a magnetic sensing element, binnacle, a non-inductive compensator for quarter deviation in the form of soft magnetic bars, which are installed in brackets on the sides of the neck of the binnacle (see page 224).

The inductionlessness of the compensator is ensured by the ratio of the dimensions of the bar and is determined by its relative length

where l is the length of the bar;

d is the diameter of the bar.

The value of Λ, at which the bar becomes non-induction, depends on the volume of the bar, its distance from the center of symmetry of the magnetic sensitive element and the magnetic susceptibility of the material. The exact value of Λ for any volume of the bar is found experimentally.

The elimination of the quarter deviation using non-induction bars is greatly simplified, since all work can be performed on the ship (ship) and there is no need to take the compass ashore to select induction plates.

However, significant disadvantages of the considered compass are:

1. The need to manufacture and equip the compass with a set of bars (from 5-6 pairs) of various volumes, having different sizes (see page 223).

2. The use of longitudinal bars of the compensator of the quarter deviation, which reduces the coefficient λ, since λ ₁ <1.

At present, in the domestic and foreign magnetic compasses, non-induction quarter-deviation compensators are used in the form of a set of thin rectangular plates having a relative length

where l is the length of the plate;

b is the width of the plate,

see the book Voronov V.V., Grigoriev V.V., Yalovenko A.V. “Magnetic compasses. Theory, construction and deviation works. Textbook ", St. Petersburg: Elmore, 2004, pp. 85-87, Fig. 43, 44 and 45.

Closest to the proposed invention in technical essence is a magnetic compass, discussed in the book "Magnetic compasses", p. 87, Fig. 45. - domestic magnetic compass KM 145-prototype.

The compass is also described in detail in Compass KM 145 Technical Description and Operating Instructions KB0.115.071 TO, p. 19, 20, 23, Fig. 1, position 4.

The compass contains a magnetic sensing element, a binnacle case, a non-induction quarter-deviation compensator in the form of a set of 16 plates that are installed in two cases, 8 plates on each side of the binnacle, tangential to the binnacle (see the book “Magnetic compasses”, page 87, Fig. 45), while the longitudinal axis of symmetry of the plates is parallel to the longitudinal axis of symmetry of the compass - its binnacle, that is, the sets of plates are longitudinal.

The main disadvantage of the prototype compass is the use of longitudinal deviation of magnetically soft plates in the non-inductive compensator of the quarter deviation, which leads to a decrease in the total coefficient λ, that is, it reduces the horizontal component of the Earth’s magnetic field at the compass location, creating prerequisites for increasing the error of its direction indication.

The main task to which the invention is directed is to increase the value of the total coefficient λ characterizing the magnetic conditions at the location of the magnetic compass, and, accordingly, reduce the compass heading error while maintaining non-inductance and compensate for the quarter deviation of the compass.

To solve this problem, in a magnetic compass containing a magnetic sensitive element, binnacle and a quarter deviation compensator in the form of sets of flat magnetically soft steel plates mounted on the binnacle and placed in planes parallel to the base of the binnacle, symmetrically with respect to the longitudinal plane of symmetry of the binnacle, the plate sets are cross-shaped and contain the rectangular parts radial and tangent to the binnacle, while the axis of symmetry of the radial and tangent parts of the plate sets are not mutually are perpendicular, the symmetry axis is perpendicular to the radial part of the longitudinal plane of symmetry of the binnacle and passes through its vertical axis of symmetry; the ratio of the length to the width of the radial and tangent parts of the plate sets is equal, and the ratio of the lengths of the radial and tangent parts is determined by the inequality

R ² (R ² + l ² ) ^3/2 ≤ (R ² + 2l ₁ ² ) (R ² + l ₁ ² ) ^3/2 ,

where R is the distance between the vertical axis of symmetry of the binnacle passing through the center of symmetry of the sensing element of the compass and the vertical axis of symmetry of the set of plates passing through the center of symmetry of the radial and tangent parts of the set of plates;

l is half the length of the radial part of the set of plates;

l ₁ - half the length of the tangent part of the set of plates.

The proposed compass is presented in figure 1, 2, 3, 4, 5, 6.

Figure 1 shows a General view of a magnetic compass with a non-induction compensator of a quarter deviation in a section.

Figure 2 presents a magnetic compass with a non-induction compensator quarter deviation top view.

Figure 3 presents a set of flat steel soft magnetic plates of a non-induction compensator of a quarter deviation top view.

Figure 4 presents the projection of the magnetic field created by the magnetization of the radial part of the cross-shaped plate by the field of the magnetic sensor on the axis perpendicular to the magnetic meridian in the center of the magnetic sensor.

Figure 5 presents the projection of the magnetic field created by the magnetization of the tangent of the cross-shaped plate by the field of the magnetic sensor on the axis perpendicular to the magnetic meridian in the center of the magnetic sensor.

Figure 6 presents the projection of the magnetic field generated by the magnetization of the radial and tangent parts of the cross-shaped plate by the field of the magnetic sensor on the axis perpendicular to the magnetic meridian, in the center of the magnetic sensor, which are compensated.

The proposed magnetic compass contains (see Fig. 1) a magnetic sensing element 1 located on a support device inside a housing 2 filled with damping fluid, a binnacle (housing) 3 with a cap 4 on the brackets 5, sets of flat soft magnetic steel are fixed in the upper part of the binnacle 3 plates 6 non-induction compensator quarter deviation. The sets of plates are placed in planes parallel to the base 7 of the binnacle 3, symmetrically with respect to the longitudinal plane of symmetry of the binnacle ХОХ.

The sets of plates 6 (see figure 2) are cross-shaped and contain a radial 8 and a tangent 9 to the binnacle 3 rectangular parts. The axis of symmetry of the radial n ₁ n ₁ (or n ₂ n ₂ ) and tangent m ₁ m ₁ (or m ₂ m ₂ ) parts of the plate sets are mutually perpendicular. The axis of symmetry n ₁ n ₁ (or n ₂ n ₂ ) of the radial part of the set is perpendicular to the longitudinal plane of symmetry of the XX binnacle and passes through its vertical axis of symmetry passing through the center of symmetry 0 of the magnetic sensor 1.

The ratio of the length (see Fig. 3) of the radial part 8 of the set 2l to its width 2d and the length of the tangent part 9 of the set 2l ₁ to its width 2d ₁ is determined by the dependence

where l is half the length of the radial part of the set of plates;

d is half the width of the radial part of the set of plates;

l ₁ - half the length of the tangent part of the set of plates;

d ₁ - half the width of the tangent part of the set of plates.

The ratio of the radial and tangent lengths of the set of plates is determined by the inequality

where R is the distance between the vertical axis of symmetry XX of the binnacle 3 (see Fig. 1) passing through the center of symmetry 0 of the compass sensing element 1 and the vertical axis of symmetry of the set of plates A ₁ A ₁ (or A ₂ A ₂ ) passing through the aligned the center of symmetry P ₁ (or P ₂ ) of the radial and tangent parts of the set of plates 6.

The proposed device operates as follows.

It is known that on any modern ship (ship), the hull and superstructures of which are made of steel, there is a weakening of the Earth’s magnetic field due to the shielding effect of the steel elements of the ship’s (ship) structures, see the book “Magnetic Compass Deviation”, p. 207 -209.

The attenuation of the Earth’s magnetic field, including its horizontal component H ₃ , is characterized by a coefficient λ ₀ (p. 208), the value of which can reach values up to 0.8 - on the roofs of wheelhouses in the places where the main compasses are installed; up to 0.6 - inside the wheelhouse in places where track compasses are installed.

In some cases, in practice, the value of λ ₀ can reach even lower values: 0.4-0.6 (p. 209). Thus, the horizontal component of the induction (intensity) of the ship (ship) magnetic field can be

that is, the induction of the Earth’s magnetic field at the compass’s location on the vessel (ship), bringing its sensitive element to the plane of the magnetic meridian, can decrease, respectively, by (60 ÷ 20)%, which leads to an increase in the compass heading error.

At the same time, nowadays widely used in the composition of visual and remote magnetic compasses of both domestic and foreign non-induction compensators of quarter deviation in the form of a set of longitudinal rectangular steel magnetically soft plates (see the book “Magnetic compasses”, p. 86), in turn, additionally reduce the Earth's magnetic field in the region of the magnetic sensing element of the compass by (10-15)%. Their coefficient is λ ₁ <1.0.

In the process of complete circulation of the vessel, that is, a change in its course of 360 °, the steel structures of the vessel are magnetized by the influence of the horizontal component of the Earth’s magnetic field. As a result of this, the deviation — the deviation of the magnetic axis of the compass sensing element from the plane of the magnetic meridian — changes, and the deviation amplitudes are the same, the number of deviations is four, and the directions of deviations alternate. These deviations - the quarter deviation - are compensated after installing on the brackets 5 in the upper part of the binnacle 3 sets of flat steel soft magnetic plates forming sets 6 of a cross-shaped shape (see figure 1). Kits 6 create, when exposed to the horizontal component of the Earth's magnetic field, weakened by shielding by ship structures, also a quarter deviation with the same amplitudes, but with opposite signs, thereby destroying the quarter deviation caused by magnetization reversal of the steel structures of the vessel. The cross-shaped shape of the compensator plate sets provides increased exposure to the Earth’s magnetic field due to the presence of radial parts of the plates directed to the magnetic sensor of the compass. The amplification is due to the predominance of the effect on the sensitive element of the compass of the field of radial parts over the field of tangent parts during magnetization of the horizontal component of the Earth’s magnetic field.

At the same time, the effect of the magnetic field generated by the sensing element on the radial and tangent parts of the compensator plates does not cause a constant quarter deviation - the deviation from the induction, which reduces the accuracy of the compass when swimming with changes in latitude. The constant quarter deviation from the induction is compensated by the same ratios of the length to the width of the radial and tangent parts of the plates and a certain ratio of their lengths.

Kits 6 may consist of solid cross-shaped plates or may be composed of alternating rectangular plates with a combination of their centers of symmetry.

The proposed device in comparison with the prototype provides improved operational characteristics of the magnetic compass due to:

1) amplification by the radial part of the set of compensator plates of the quarter deviation of the horizontal component of the Earth’s magnetic field in the area of the magnetic sensitive element of the compass, weakened by its screening by ship structures and the tangent part of the set of plates of the compensator;

2) strengthening the horizontal component of the Earth’s magnetic field reduces the compass heading error;

3) the strengthening of the horizontal component of the magnetic field will allow the compass to be placed in enclosed spaces of ships limited by steel decks and bulkheads, where compasses with existing quarter deviation compensators have large errors or lose their operability.

Theoretical supplement to the invention “Magnetic compass”.

To meet the requirement _of non-inductance at the same time and to obtain the coefficient λ _{1 of the} compensator λ ₁ ≥1.0, transverse, radially directed, are added to the longitudinal rectangular plates tangent to the binnacle.

Let us compose an expression for the projections of the magnetic field created by the magnetization of the radial part 8 of the cross-shaped plate by the field of the magnetic sensor 1 on the axis perpendicular to the magnetic meridian N _M , in the center 0 of the magnetic sensor 1 (Fig. 4).

where H ^p _1n , H ^p _2n - projection of the tension caused by the transverse and longitudinal non-magnetizations of the radial part of the plate;

æ ^p ₁ , æ ^p ₂ - magnetic susceptibility of the radial part of the plate along the longitudinal and transverse axes, respectively;

V _p is the volume of the radial part of the plate;

θ is the angle between the longitudinal axis of the plate and the perpendicular to the magnetic meridian;

M is the magnetic moment of the sensing element of the compass;

φ is the angle between the field strength vector H of the sensing element in the center of the plate and the longitudinal axis of the radial part of the plate;

R is the distance between the centers of symmetry of the sensing element and the radial part of the plate;

l is half the length of the radial part of the plate.

We compose a similar expression for the tangent part of the plate 9 (figure 5):

и

проекции напряженности, вызванной продольной и поперечной намагниченностями касательной части пластины;Where

and

projection of tension caused by the longitudinal and transverse magnetizations of the tangent part of the plate;

V _k is the volume of the tangent part of the plate.

For non-inductance, the equation must be satisfied (Fig.6)

Given that both parts of the plate have the same thickness, θ = 45 °, æ ^p ₂ << æ ^p ₁ , æ ^k ₂ << æ ^k ₁ , for æ ^p ₁ = æ ^k ₁ we obtain by introducing (7) and (8 ) at 9):

where d and d ₁ are half the width of the radial and tangent parts of the plate.

In addition to the requirement _of non-inductance, there is a requirement λ ₁ ≥1.0, which can be expressed by the inequality:

After reduction (æ ^p ₁ = æ ^k ₁ ) we obtain

For the simultaneous fulfillment of conditions (10) and (12), we can obtain the value l ₁ d ₁ from (10) and substitute it in (12). After the transformations, we obtain the inequality

Inequality (13) is given in the claims of the application for the invention.

Literature

1. Kozhukhov V.P., Voronov V.V., Grigoriev V.V. Deviation of a magnetic compass. L .: Maritime transport, 1960, p .98, 199, 207-221, 223, 224.

2. Voronov VV, Grigoryev VV, Yalovenko A.V. Magnetic compasses. Theory, construction and deviation works. Tutorial. St. Petersburg: Elmore, 2004, p. 85, 86, 87.

3. Compass KM 145. Technical description and operating instructions for KB0.115.071 TO, p. 19, 20, 23.

Claims (1)

A magnetic compass containing a magnetic sensing element, binnacle and a quarter deviation compensator in the form of sets of flat steel soft magnetic plates mounted on the binnacle and placed in planes parallel to the base of the binnacle, symmetrically with respect to the longitudinal plane of symmetry of the binnacle, characterized in that the plate sets are cross-shaped and contain the rectangular parts radial and tangent to the binnacle, while the axis of symmetry of the radial and tangent parts of the plate sets are mutually perpendicular are equal, the axis of symmetry of the radial part is perpendicular to the longitudinal plane of symmetry of the binnacle and passes through its vertical axis of symmetry; the ratio of the length to the width of the radial and tangent parts of the plate sets is equal, and the ratio of the lengths of the radial and tangent parts is determined by the inequality R ² (R ² + l ² ) ^3/2 ≤ (R ² + 2l ₁ ² ) (R ² + l ₁ ² ) ^3/2 , where R is the distance between the vertical axis of symmetry of the binnacle passing through the center of symmetry of the sensing element of the compass and the vertical axis of symmetry of the set of plates passing through the center of symmetry of the radial and tangent parts of the set of plates; l is half the length of the radial part of the set of plates; l ₁ - half the length of the tangent part of the set of plates.

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