Dumpy Level Surveying – Components, Procedure, Advantages

What is the meaning of Dumpy Level? A dumpy level is a common levelling tool for locating points in the same horizontal plane. It’s also known as a builder’s level or an automatic level. Dumpy level can determine the elevations of distinct points and the distance between points of the same elevation. Because the telescope is attached to its supports in a dumpy position, it cannot be rotated in the vertical axis. William Gravatt created it in 1832. Level Surveying is a clumsy process.Dumpy Level Components Dumpy level is made up of the following parts or components. Telescope Tubes with bubbles Compass Spindle that is vertical Screws for the tribrach Screws for the feet Tripod with levelling head.

Telescope

Telescopes are used to observe distant objects using the line of sight offered by their configuration. The telescope is generally attached to the vertical spindle of the dumpy level so that it can rotate with it.Telescope Parts at Dumpy Level The following are the main components of a telescope: Objective lens for eye piece eye glasses The observer’s eye uses an eye piece to examine a distant object. It has a magnifying lens that magnifies the observing image as well as diaphragm cross hairs. As a result, precise readings can be obtained. The typical picture is viewed through an erecting eyepiece, which is inverted by the objective lens.a lens that is objective The telescope’s objective lenses are located at the opposite end.

The telescope’s objective lenses are located at the opposite end. The objective lens is made up of two parts: a convex type lens on the front and a concave type lens on the back. As a result, the image produced by the objective lens is inverted at all times. Diaphragm In front of the eyepiece, there is a diaphragm. It has dark metal cross hairs that are set in exact perpendicular positions. The eye piece uses these cross hairs to bisect the objective through the objective lens. Diaphragm at Dumpy Level Diaphragm at Dumpy Level Diaphragm at Dump Screw for focusing The focus of cross hairs and visual clarity are adjusted using the focusing screw. This focusing screw controls the magnification of the eye piece. Rays of light Ray shade is used to keep the sun out of the room.

Tubes with bubbles

Bubble tubes are provided to check the instrument’s level. A dumpy level contains two bubble tubes that are positioned perpendicular to each other on the top of the telescope. The longitudinal bubble tube is one type of tube, while the cross bubble tube is another. When both of the tubes’ bubbles are in the centre or middle of the tube, the instrument is said to be in perfect position. Compass The magnetic bearing of a line is determined using a compass. A circular compass is located right beneath the telescope in case of a dumpy level. The compass has a pointer and readings are written on the inside. When the pointer is facing north, it is set to zero.

The vertical spindle is positioned in the instrument’s middle. With relation to the vertical spindle, the telescope can be rotated horizontally. The vertical spindle connects the instrument to the tripod platform. The levelling head or trivet is parallel to the Tribrach plate. It is attached to the trivet using levelling screws or foot screws that allow the tribrach plate to be adjusted. This tribrach plate can be adjusted to raise or lower the instrument’s horizontal level. Dumpy Level Tribrach Screws for the feet The instrument can be levelled by using the foot screws to regulate the tribrach position, which can be determined by looking at the bubble tube. Foot screws can be used to lower or raise the tribrach plates. The tribrach’s position is said to.

Procedure of Dumpy Level Surveying

Trivet is another name for a levelling head. It consists of two triangular-shaped plates that are parallel to one another. At the three corners of the plates, there are three groves in which foot screws can be supported. The top of the tripod is used to support the entire levelling device. It has three legs that can be adjusted to the desired position. Legs might be solid or hollow, and they are all the same height. At the bottom of each leg, steel shoes are given to keep the ground in place. Dumpy Level Tripod Dumpy Level Surveying Procedure The process of dumpy level surveying begins with a few interim changes, which include: Setup of the instrument Increasing your focus level Dumpy is being set up.

Clamp screws secure the instrument to the tripod stand. Position the device at a comfortable height by spreading the tripod legs. Fix the two legs in the ground at a spot, then adjust the third leg to centre the bubbles in the bubble tubes. Increasing your skill level Foot screws or levelling screws are used to adjust the level of an instrument. The telescope is aligned parallel to any two levelling screws in this example, and the bubble in the tube is centred by rotating both screws inwards or outwards. The telescope is then turned 90 degrees and the third screw is twisted until the bubble is centred. Rep the procedure until the tube’s bubble has dissipated.

Focusing

Adjusting the eye piece and focusing screw allows you to fine-tune your focus. The eyepiece is adjusted until the diaphragm cross hairs are plainly visible. A white paper is used to eliminate the parallax error and obtain sharp vision of cross hairs. To see a crisp image of the objective or staff, the focusing screw is adjusted. When the cross hairs bisect the objective or staff with clear vision, it is said to be focused. It’s now time to take levels of required positions or points after completing the above temporary changes. The telescope is turned so that it bisects the objective or staff line. The levels are recorded at several locations, with values determined by a known benchmark point in the area.

Dumpy Level Surveying’s Advantages The Dumpy level is simple to utilise. On any sort of ground, adjustments can be made to meet the needs. In the case of a dumpy level, level readings are extremely precise. For a dumpy level, the optical power is quite high.When compared to other instruments, the price of a dumpy level is low.Dumpy Level Surveying’s Draw backs It is only capable of measuring horizontal angles. Dumpy’s angles aren’t particularly precise. The dumpy level is an optical tool that is used for surveying and levelling. It is made up of a telescopic tube that is securely kept in place by two collars and adjustable screws. The vertical spindle controls the entire instrument. The telescope can be rotated in the horizontal plane when it is positioned on the dumpy level.

Principle of Dumpy Level Instrument:

Through an inbuilt telescope and a bubble level, the dumpy level works on the premise of establishing a visual relationship between two or more points. Steps can be taken to attain the desired level of precision. Surveyors levels, Builders levels, Dumpy levels, and even its prehistoric version “Y(Wye) Level” are some of the other names for it. Dumpy level accuracy vs. other levelling instruments: The accuracy of Dumpy level vs. other levelling instruments is the primary reason for its use. For most Tacheometric approaches, a dumpy level is recognised for having high accuracy values. A dumpy level’s accuracy can be as high as 1:4000 for every 100 metres. Use of a Dumpy level in Surveying: When surveying a construction site, the use of a Dumpy level is critical.

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