Instrument for measuring relative height: description, purpose, classification of devices

This article is devoted to devices that measure the parameter such as height. However, before proceeding with the description of the instrument itself, let's look at what this indicator represents.

The notion of height

The parameter is a relative value, that is, this value is always determined with respect to something. Most often it is measured relative to sea level, which means that the sea surface line is taken as the reference point. Such a system resembles the definition of the degree of water in Celsius, when the reference point is the temperature of the transition of water from the liquid state to the solid state, and vice versa. Similarly, with a measurement of altitude, a positive value is considered above sea level, and a negative value is lower. In special cases, any other surface can be chosen as a reference point. For example, no one will measure the height of the house with respect to sea level, here the reference point is the surface of the earth on which the building is built. The same principle is used to measure all the particular cases: the height of the tree, the structure, etc. But the height of the mountain or any point on the earth's surface, as well as the object flying in the atmosphere (aircraft, helicopter, etc.) is measured relative to sea level. The reader may ask the question: "And what is the common practice of using the device to measure the relative height?" You will find the answer to this question if you read the article to the end.

Instrument for measuring relative height: history of development and main types

Since ancient times, people used to build and define the relief such a tool as the level. This device became the basis for a modern measuring mechanism. An old tube was attached to the ancient level, and it turned out the most elementary device for measuring relative height, which was called the level, which means "leveling". Elementary level is a horizontal rack and a vertical bar to which a plumb line is attached. However, with the development of science, tools are being perfected. The altimeter was no exception. Thus, modern levels can be divided into three main groups. The first - the most common, it includes devices based on high-quality optics. The second group is laser devices. These devices are characterized by high-precision measurements. And the third - the most "young" - is the digital levels.

Optical measuring instruments

Such a device is a cylindrical level (or compensator) and an optical system that is placed in a metal casing (tube). The level is required to set the sighting axis to the horizontal position. For the measurement, the level is set on a tripod with a support pad. The cylindrical level is an ampoule with a liquid (ether, alcohol). Part of the space filled with alcohol pairs is called a level bubble. On the upper surface of the ampoule, a scale is plotted with a step of two millimeters, its middle point being called the zero line.

Laser Level

In these devices, in addition to optical systems, laser light-emitting diodes have come, but, in fact, the named device differs little from the optical one. Its main feature is a very thin, perfectly smooth beam projected onto the measured surface. This greatly simplifies the process of determining the height.

Digital instrument for measuring relative height

This tool is very different from its predecessors. He not only changed his appearance and internal structure, but also significantly expanded his capabilities. The digital level is a measuring device that is able not only to measure, but also to project rays, planes onto any surface. This tool is simply indispensable for construction and repair work. This device is characterized by high measurement accuracy and ease of use, even novice can use this tool.

Principle of operation of the digital level

The basis of the device under consideration is the electromagnetic system of pendulums and an LED (laser) optical system, which is designed to project laser beams in the form of dots or lines. One such device can project several planes at once, which is very convenient for construction. To ensure the accuracy of measurements in the digital level, a metal pendulum is used, which aligns the entire electronic and optical part of the device with respect to the ground level. Even if the device is inaccurate or moved during operation, the pendulum will put the circuit parallel to the ground, and the projected surface will remain accurate. Consider how this happens. There are several electric or natural magnets under the pendulum. Thanks to the created magnetic field, the swing of the pendulum is prevented when the position of the level is changed. When you install the device, this element swings freely. However, when passing through a magnetic field in a material (metal), an electric field is induced, transformed into thermal energy, which also hinders the entire system.

The optical system of the device is built on LEDs that create horizontal, vertical and diagonal rays. Passing through the system of lenses, they are converted into lines, which are projected on the measured surfaces.

Advantages and disadvantages of digital levels

The main advantage of this device is its simplicity and visibility, as well as the ability to work with the reference plane at several points simultaneously. We should also mention the possibility of constructing horizontal and vertical planes, and immediately in different directions.

The disadvantage of the device in question is its high cost. Of all of them, only devices of the third class are commensurable at a price with optical levels. They can be used only when performing repair work indoors, where high accuracy does not play a big role. For example, for marking floors, walls, ceilings. And for conducting geodetic measurements and for marking grandiose objects under construction, instruments of the first or second accuracy class are required . However, the range of such instruments is still limited to 600 meters. If it is necessary to carry out measurements over long distances, optical levels should be used.

Classification of digital levels

1. Point device for measuring height. It resembles a laser pointer, that is, projects one or more points onto the measured surface.

2. Static, or position digital level. This device has two sources projecting laser beams onto perpendicularly placed prisms, which convert them into two visible planes. As a result, two crossed planes are obtained. In the case of using complex optical systems containing more than three semiconductor diodes, it becomes possible to project a large number of planes, which is very useful when working with multidimensional objects. In addition, the more planes, the more masters can engage in repair or construction work. The positioning levels are also equipped with a "laser plummet" function. These are additional diodes, due to which it is possible to direct the beam simultaneously to the floor and to the ceiling.

3. Rotational digital level. In such a device, the laser is attached to the shaft of the electric motor, that is, it can rotate 360 degrees. In addition, in such devices (instead of a prism) a focusing lens is used. As a result, instead of a plane, a person sees a small point, but when switched on, a continuous line is projected across the entire working area or area of the room.