1. Definition of Level Meter

A level is a common measuring tool for measuring small angles. In the machinery industry and instrument manufacturing, it is used to measure the inclination angle relative to the horizontal position, the flatness and straightness of the guide rail of machine tool equipment, the horizontal position and vertical position of equipment installation, etc. The spirit level is mainly used to test the straightness of guide rails of various machine tools and other types of equipment and the horizontal and vertical positions of equipment installation. It can also be applied to the measurement of small angles and working surfaces with V-shaped grooves, and can also measure the installation parallelism of cylindrical workpieces, as well as the horizontal and vertical positions of the installation. The spirit level is an indispensable precision measuring tool for mechanical equipment installation and measurement of levelness and verticality.

2. Level classification

2.1. According to the shape of the level, it can be divided into: universal level, cylindrical level, integrated level, mini level, camera level, frame level, ruler level.

2.2. According to the fixing method of the level, it can be divided into: adjustable level and non-adjustable level.

2.3. Classified according to the material: the level can be divided into plastic level, glass level, plastic level has low precision, and glass level has relatively high precision.

3. Calibration method

3.1. Calibrate the parallelism of the horizontal bubble axis

The method of calibration is to first rotate the foot screw to move the circular level bubble to the middle, and then use the calibration needle to move the screw under the circular level to center the bubble, and then repeat this operation until the bubble is no longer offset.

3.2. Calibration of cross wire and horizontal wire

The correction method is to loosen the three fixing screws of the cross ring. Gently rotate the crosshair ring in the opposite direction of the crosshair tilt so that the crosshairs are level. Repeat the two-step check and calibration until the horizontal thread is level. Finally, tighten the screws.

3.3. Calibration of level tube axis

Select two points about 80m apart on flat ground and mark them. Place the level at the midpoint C between point A and point B, and measure the height difference between point A and point B by changing the height of the instrument or using the double-sided ruler method.

Then move the instrument near point A (or point B). Generally, the distance between the eyepiece of the spirit level and the scale surface is about 2cm, and then read the reading of the small circle on the scale surface from the objective lens. Read the altitude difference between point A and point B again. If the height difference between the two measurements is greater than 5mm, it needs to be corrected. Turning the slight tilt screw corrects the scale reading for points away from the instrument on the rack so that the difference in height between the two measurements is equal. At this point, the reading near the ruler surface is accurate by default. At this point, the collimation axis is already horizontal.

3.4. The principle of level tube axis calibration.

If the axis of the vial is parallel to the collimation axis, then both are horizontal, and no matter where the instrument is placed at points A and B, you will get the same height difference, and non-parallel will form an I angle. Obviously, when the instrument stand is at the midpoint of AB, the influence of I angle can be eliminated.

So the height difference at this time is also accurate. When we measure directly near A (or B), all reading errors fall on B (or A). At this point, adjust the slight tilt screw to make the height difference between the two measurements equal, thus ensuring that the collimation axis is level.