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Ruian Shunfeng Navigation Instruments Co.,Ltd

Add: No.20, Heping Road, Jinhu Street, Ruian, Zhejiang, China
Con: april Zhang
Tel: +86-577-65520898
Fax: +86-577-65966926
Mob: +8618158321811

Seeking the introduction of the compassion?

Provide the direction of the instrument. The ship is used to determine the heading and the orientation of the object. Luo by the magnetic compass and gyrocompass by two, the general sea are equipped with magnetic compass and gyro compass. The former is simple and reliable, the latter is easy to use and accurate.

Magnetic compass made by the use of free support of the magnetic needle in the geomagnetic stability of the north of the characteristics of the compass. Magnetic Luo by China's Secretary South, compass gradually developed from.

Si Nan for the natural magnet made of spoon-like, cast on a smooth site, stop when the spoon handle guide. The site is surrounded by gossip and Heavenly Stems name, used to express the position. Known about the first note of the Secretary of the South in the third century BC, the end of the Warring States period, "Han Feizi degree." The beginning of the Song Dynasty appeared artificial magnetized compass, there are water floating, silk hanging, needle top and other methods, modern magnetic compass and geomagnetic measuring instruments still use these basic structure. The Northern Song Dynasty Shen Kuo in the "Mengxi Bi Tan" (1063 years) describes the use of magnet grinding needle compass method, and documented the existence of magnetic differences.

Compass is the primary stage of the magnetic compass, is one of the four ancient Chinese invention. During the Tang and Song dynasties, China's overseas trade was very well developed. Large merchant ships voyed to the Persian Gulf, the Red Sea and other places. Shipbuilding and navigation technology were at the forefront of the world. Compass used in the sailing of the earliest recorded in the Northern Song Dynasty Zhu Yu's "Pingzhou can talk" (1119), the book said: "boat teacher geography, the night is the concept of stars, day view of the day, Yin looked at the compass. The compass in the sailing is also called the compass. Ming Dynasty copper water compass with eight dry, twelve, four-dimensional hexagram name marked twenty-four positions. It is generally believed that the compass is passed from China to Arabia and then to Europe, but there is controversy.

According to legend, the beginning of the 14th century, the first Italian Amalfi F. Josia first paper Luo card (that is, the direction of dial) and magnetic needle connected together to turn. This is a leap in the development of magnetic compass. Since then the ship is no longer need to turn the compass by hand. 16th century the Italian Calder made a balanced ring, so that the magnetic Luo in the ship can also maintain the level of shaking. At the beginning of the twentieth century the British E. Harry made the first world and other magnetic difference curves.

Iron boat appeared, the magnetic compass produced self-difference. Prior to this, the description of the phenomenon of self-difference has been seen in the late Ming and early Qing Dynasty side of the wisdom of the "little physics", the book said the iron on the magnetic needle interference and the ship did not nail reasons: "marui, And the nonsense also. "The first half of the nineteenth century the British M. Flinders and GB Alley has proposed to eliminate the self-difference method, the French Poisson on the self-poor mathematical theory has contributed. In the 1870s, British physicist W. Thomson made the stability of the dry Luo installed in a similar modern self-messenger compass, was the British Navy as a standard equipment. At the beginning of the twentieth century, the performance was more stable, and the needle was less friction, made of liquid compass, which has now been used by most ships.

Structure: magnetic compass mainly by the compass and compass basin composed of two parts. A compass card with a magnetic needle is installed in the compass. Magnetic compass by structure can be divided into dry Luo and liquid compass by two; according to the use can be divided into standard compass, steering compass, emergency compass, boat with compass and so on. Modern ships and more in the top of the deck on the open deck can be installed on the compass card reading into the cab of the standard compass, can also serve as the steering compass. This kind of compass has two kinds of reflection and projection, and their basic structure is similar to ordinary compass, only a set of optical projection system.

Compass difference includes magnetic difference and self difference. Magnetic difference is due to the magnetic pole and the ground is inconsistent and exists in the magnetic north and north of the angle between, also known as magnetic declination. As the magnetic pole around the ground for a slow cycle of movement, so the magnetic differences in different places, there are changes every year. There is a magnetic anomaly on the surface of the earth, and the magnetic difference in this area is significantly different from that of the surrounding area. The brook on the chart is marked with a local magnetic difference and annual rate of change, the use of magnetic compass can be corrected to read. Since the difference is due to the iron and steel magnetism on the ship caused by the magnetic force on the magnetic compass, the magnetic needle from the magnetic north, the formation of the angle even up to several degrees. The ship has a difference from hard iron and soft iron. Hard iron such as carbon steel, cobalt steel is magnetized with permanent magnetic; soft iron such as wrought iron, silicon steel leaving the magnetic field after the magnetic induction soon disappeared. They are caused by the differences have their own changes in the law. Correction of self-difference is to produce the opposite force with the ship magnetism correction on the compass around, respectively, with the magnetic and soft iron to offset the permanent ship magnet and the magnetic induction of the magnetic needle. After the correction of the remaining self, the measured made from the difference table or self-difference curve, the absolute value should not be greater than 3 °. The main feature of the difference is that with the course of change, different routes to use the corresponding self-correction.

Gyrocompass, also known as the Gyrocompass, is the use of gyroscope two basic characteristics of the fixed axis and forward, combined with the Earth's rotation vector and gravity vector, with the control equipment and damping equipment made of a true North reference Point to the instrument. Gyrocompass is made according to the French scholar L. Fu Ke in 1852 proposed the use of gyroscope as the principle of pointing to the instrument and manufacturing. German Anshu in 1908, the American EA Seperry In 1911, the British SG in 1916 were made in 1916 to their names named after the three different gyro compass, the Bronro later developed into Ama - Bronro. Now these three kinds of compass are each form a product line.

Gyrocompass is usually composed of the main compass and ancillary equipment. The ancillary equipment includes power converters, control boxes or control boxes and sub-compasses, etc., is necessary to ensure that the main work of the main equipment. In order to reduce the number of parts of the gyrocompass, the power converter can be assembled with the control box, can also be assembled with the main compass. The main compass can usually take 8 to 20 sub-compass, to show the main compass of the course. Modern gyrocompass toward the small size, light weight, long life, easy maintenance, easy operation and can be applied to large, medium and small ship trends. Such as replacing the inverter with an inverter, replacing the tube with a solid-state element, replacing the contact transmitter with a contactless transmitter. The sensitive parts of the new gyrocompass are generally made of sealed balls and are specially supported by liquid to improve their accuracy and reliability.

Type: Gyrocompass according to the role of the gyroscope on the way the moment can be divided into mechanical tilting and electromagnetic control of two categories.

① mechanical pendulum gyro compass: according to the way to produce the pendulum moment can be divided into two kinds. One is the elastic support of the single rotor on the heavy iron plate, or liquid communication device type, such as the Perry type gyro compass; the other is the gyroscope center of gravity placed under the support center, called the next Heavy compass, such as the Anchutz type with liquid floating bearing double rotor under the heavy compass.

These two ways produce the opposite of the direction of the moment, and their momentum moments are in the opposite direction. Liquid Faucet Brochure Momentum Moment Vector Guide, the weight of the lower compass vector vector north. Under the action of the pendulum moment, the north end of the mandrel of the mechanical pendulum will swing around the meridian surface, and its trajectory is an ellipse on a sphere. The mechanical pendulum of the dampers is fitted with the dorsal wobble in the north end of the spindle and stabilized with respect to the meridian surface in order to provide a true north reference.

The flexible part of the liquid connector type compass consists of gyro motors and brackets, which are suspended by wire and use the negative effect of the mercury generator to produce the control torque. The sensitive part of the heavy-duty compass is a sealed gyro ball with two gyro motors, light-shaped brackets and dampers with the same parameters (Figure 8). The two gyro motors are supported vertically on the lamp holder and are connected to each other by a crank link and spring and are at an angle of 45 ° to the north and south of the gyro ball spindle. With this device, the two gyro motors can only rotate in the opposite direction about their vertical axis, with the same angle of rotation, but the angle is very small. Therefore, they synthesize the momentum moment vector is always consistent with the north and south of the gyro ball spindle, similar to the role of single rotor, with two gyro motor can effectively reduce the swing error.

② Electromagnetic control type gyro compass: In the structure of the two-degree-of-freedom balance gyroscope, a set of electromagnetic control device composed of electromagnetic pendulum and torque device is arranged. The gyro compass (Fig. 9) Controlled compass. Because the electric signal is easy to control, it can change the size of the control torque as needed to achieve fast and stable compass. The Ama-Brown-type compass is a typical electromagnetic controlled compass. Made in China CLP-1 type compass is the electromagnetic control type gyro compass used in civil ships (see color chart).

The most common gyro devices in mechanical pendulum compass and electric control loops are ball gyroscopes and liquid floating gyroscopes. After the emergence of liquid floating gyroscope, but also the development of flexible gyro. Its support system does not use conventional gyro frame bearings and flexible joints. Flexible gyroscope has a simple structure, small size, light weight, long life, high reliability, has been applied in the ship. The flexible gyro compass is still an electrically controlled compass for its principles.

Error: Gyrocompass has latitude error, velocity error, impact error, swing error and baseline error. The use of vertical axis damping method of the gyrocompass have latitude error, which is a principle error. The velocity error is independent of the meridian structure parameters and is related to the speed, heading and latitude of the ship. Latitude error and speed error are regular, available look-up table method, mobile baseline or dial method, torque compensation method to be amended. The impact error caused by the influence of inertial force on the gyrocompass by navigating the ship can be eliminated by cutting the damper and making the equatorial swing period equal to 84.4 minutes or cutting off the electromagnetic pendulum. Gyrocompass has the ability to reduce the swing caused by the ship swing caused by the device, so this error is generally not considered. The baseline error due to poor installation of the main compass or sub-compass is a fixed error that can be corrected by rotating the main compass or dividing the base so that the baseline is parallel to the bow tail. In the calm sea, the ship constant speed constant navigation, the modified gyro compass error should not be greater than 1 °.

Ruian shunfeng navigation instruments co.,ltd


Con:april Zhang