Spirit level
The water level ( indicative scale or Maurer scale ) is a test device for horizontal or vertical orientation of an object and consists of a broader spirit level which is aligned with the measuring surfaces. Originally the term spirit level referred to a contained dragonfly, the setting of which is not significantly larger than this dragonfly and has a flat side. Because of the shortness of such a spirit level, you can only use it to check individual objects such as beams or stone blocks for horizontal position. In order to be able to check composite structures, such as a wall or paving , this spirit level was placed on a longer strip (mostly hardwood). The slope of a channel or a paving can be checked by measuring or by experience with the point where the dragonfly enters. A mark ( pars ) on the left and right of the dragonfly, which usually corresponds to a deviation of one degree, is common.
Indicative scale, also Maurer balance (as a tool of Mason ), refers to a test device having one or two vials (even more are possible), the length in a 30-200 cm profile from aluminum - construction profile , wasserunempfindlichem, stable hardwood , aluminum casting, plastic o. are embedded with one or two measuring surfaces. These measuring surfaces can be milled or coated. With two vials, these are installed perpendicular to each other in such a way that both the horizontal and the vertical can be checked. There are also spirit levels with three dragonflies; the third vial is then intended for checking the 2 ° inclination (slope of sewer pipes) or 45 ° inclination. There are also some rotatable vials that can be adjusted to certain values on a scale .
Spirit levels with a length of more than 200 cm are rare and are often incorrectly called straight lines . Spirit levels can also be used for the function of a straight line at the risk of soiling and wear, but they clearly differ from this object in the presence of dragonflies. The profile of real straight logs is typically around twice to three times as high as that of a spirit level.
Nowadays, masonry scales of various lengths are almost exclusively made with two dragonflies and these are generally referred to as spirit levels .
Special designs
While the spirit level is actually a tool that is only used to install individual components, for example stones, bricks , pipes , beams and not to measure structures over greater distances, there are other forms such as the cord spirit level, post spirit level or the laser spirit level.
The cord spirit level is a mounted dragonfly with two eyelets so that you can knot them in a cord , for example a batter board. Because of the sagging of a horizontal cord and the susceptibility to wind and vibrations, this can only serve as a rough guide. The line spirit level should hang as precisely as possible in the middle and the line should be kept very tight.
The spirit level in machine is a special form of the normal directional scales here since accuracies in the range up to 0.01 mm are required to 1 m length.
The laser level has a laser whose beam is offset in height by a few centimeters and shines parallel to the sole of the level. A laser unit consisting of a laser diode , control electronics and a lens for aligning and focusing the laser beam is built into the profile of a spirit level. The laser beam is then adjusted to the measuring surface of the spirit level. The accuracy of the laser level essentially depends on the individual accuracy and the interaction of the individual components of the level, level profile and laser unit. Cheap laser spirit levels from the discounter often have poorer accuracies (more than 1 mm / m) or do not even have an accuracy specification. In addition, there are poorly installed and insufficiently adjusted laser units or vials. For transferring a height, for example a meter mark , there are laser spirit levels with a leveling plate that can be set up on a tripod or other fixed position. While a normal hose level or a leveling device can only be used by two people, a worker can transfer a height with a laser level. The range of the laser beam depends heavily on the ambient brightness and the wavelength of the laser diode. Good laser spirit levels have a range of 30–40 m under normal construction site conditions. A leveling device or rotating laser should be used for greater ranges and accuracy .
Measurement accuracy
The measuring accuracy is usually indicated on the spirit level in mm / m, but also in degrees and can be confirmed by an official test office with a seal . It only describes the maximum measurement error for measuring over a distance with the length of the respective spirit level and not for checking two points with a distance of a few cm and also not for a measurement with intermediate points, for example at a distance of 1 m with a 40 cm long spirit level.
The measuring accuracy depends on the quality of the vial, the installation accuracy, the aluminum profile / wooden body and the accuracy of the setting edge. It can deteriorate through improper handling (shocks, loads, extreme temperatures and especially with wooden spirit levels through moisture or even wetness), incorrect storage, insufficient care or aging.
Usual measuring accuracies in normal position when new:
- 0.057 °, this corresponds to 1 mm / m
- 0.0285 °, this corresponds to 0.5 mm / m
With a simple scale printed on it, a tube level can also be used for direct measurement of slopes.
The correct function of a spirit level is checked by turning it 180 ° and placing it on the same surface. If the spirit level shows the same inclination in both measurements, the spirit level is accurate; if there is a deviation, its size shows the inaccuracy.
history
The ancient Egyptians already used the water to build the pyramid base plate by dug a rectangular trench around the planned construction site and filled it with water. Everything that was above the waterline between the canals has been removed. In this way, accuracies of 2 cm could be achieved.
In ancient times was as plumb level an isosceles triangle used in which a solder (sinker) was suspended. The plumb line points to the center of the base of the triangle when this is level.
In 1661 Melchisédech Thévenot developed the first usable spirit level with encapsulated liquid. This still had two banana-shaped capsules and was relatively complicated to use. Soon people started using alcohol instead of water to increase frost resistance. The current design with a single, only minimally curved capsule was created in the 1920s.
Other tools with a similar function
- The setting bubble corresponds to the spirit level, only it is 100 times more accurate
- The leveling scale (sewer scale) is a simple geodetic measuring instrument.
- With gradient diameters and inclinometers any angle can be measured from the horizontal.
- With the hose level , a certain height can be transferred horizontally without a line of sight.
- The circular level is used for rough alignment in two dimensions, e.g. B. in the construction of the tripod of optical devices, and consists of a glass vessel which is ground spherically round at the top and has one or two marking circles above it in the middle.
Web links
Individual evidence
- ↑ Wolfgang Nutsch and others: expertise for carpenters (12th edition), published by Europa-Lehrmittel, Wuppertal 1980, page 232, ISBN 3-8085-4011-7
- ↑ Heinz-Dieter Haustein: Universal history of measuring - To measure and number, money and weight , Directmedia Publishing , Berlin 2007, digital library , volume 164, ISBN 978-3-89853-564-9