The vial of a spirit level is made of glass; the inner wall of the vial features a curved surface with a specific radius of curvature. The vial is filled with a liquid; when the spirit level is tilted, the bubble inside the vial moves toward the higher end of the instrument, thereby indicating the position of the horizontal plane. The larger the radius of curvature of the vial's inner wall, the higher the resolution; conversely, the smaller the radius of curvature, the lower the resolution. Therefore, the radius of curvature of the vial determines the precision of the spirit level. Spirit levels are primarily used to inspect the flatness, straightness, and perpendicularity of various machine tools and workpieces, as well as to verify the horizontal alignment during equipment installation. This is particularly useful when measuring perpendicularity, as a magnetic spirit level can adhere directly to a vertical working surface without requiring manual support; this reduces physical exertion and eliminates measurement errors caused by body heat radiation affecting the instrument.
The spirit level features a right-angle structure with base and side lengths of 2000 mm. Its standard precision typically ranges from 0.02 to 0.025 mm/m; however, custom specifications can be provided upon request to meet specific user requirements. The spirit level's zero-adjustment mechanism possesses unique design features that offer distinct advantages over conventional structures: 1. Zeroing is easily accomplished. 2. Once adjusted, the zero position remains stable and is not prone to drifting. If the bubble shifts when the V-grooved base of the spirit level is rotated by 5 degrees around a central axis, the alignment can be corrected by adjusting screw. 3. This adjustment is typically calibrated at the factory and generally requires no further modification.
The structural design of a spirit level varies depending on its classification. A frame-type spirit level typically consists of the main body, a transverse vial, heat-insulating handles, a main vial, a cover plate, and a zero-adjustment mechanism. A ruler-type spirit level generally comprises the main body, a cover plate, a main vial, and a zero-adjustment mechanism.
A spirit level is a measuring instrument that utilizes a vial (or bubble tube) as its primary element for measurement and reading. The vial is a sealed glass tube wherein the longitudinal cross-section of the inner surface forms a curved arc with a specific radius of curvature. The glass tube is filled with a liquid characterized by a low viscosity coefficient-such as alcohol, ether, or a mixture thereof-while the unfilled portion of the tube is commonly referred to as the "spirit bubble." A specific relationship exists between the radius of curvature of the longitudinal cross-section of the inner surface of a glass tube and its graduation value; based on this relationship, the inclination of a measured plane can be determined.
