Month: October 2020

Level gauges are meters used to determine the level of a liquid in a fixed storage or process tank. The gauge is composed of several parts including head, float, measuring tape, bottom anchored bracket, guide wires, elbows, anchors, coupling, pipe support brackets, and pipework. Liquid level gauge calibration is used to ensure proper readings are obtained when using level gauges.

Level gauges have several advantages including durability for harsh environments, including the ability to withstand high pressure, temperature, and vibrations. They are easy to read from a distance and can be used in addition to a switch or alarm in a system. There is little maintenance required and all repairs can be done without disturbing the system. They can also be customized for extreme applications.

There are several basic types of level gauges. Examples include:

Tank level gauges – A tank level gauge is used in tank volume monitoring.

Fuel level gauges – A fuel level gauge provides a direct fuel level reading for vehicles and equipment. The two main parts of a fuel gauge are the sender and the gauge. The sender measures the fuel level in the tank and the gauge displays the level to the user. The sending unit measures the fuel once the float has dropped below a certain level. When the tank is full, the float is near the top and the wiper rests close to the grounded side. This means that the resistance is small and a relatively large amount of current passes through the sending unit back to the fuel gauge. As the gas level drops, the float also begins to sink and the wiper moves to increase the resistance and cause the amount of current sent back to the gauge to decrease. To watch an animation of this level system, click the image below.

Water level gauges – A water level gauge is used for measuring the rise and fall of water levels.

Mechanical level gauges – A mechanical level gauge monitors levels of underground storage tanks.

This article comes from globalspec edit released

Working Principle

Apart from glass tube level gauges, transparent level gauges are always fitted with two plate transparent glasses between which the fluid is contained. The fluid level is indicated as the result of the different transparency of the two media and in some cases (for water steam), by conveying upwards on to the surface of separation (between liquid and gaseous substances) a source of light located at the back of the gauge, the rays of which are totally reflected down to the observer.

Applications

Transparent level gauges are suitable for almost all installations.

In fact they permit:

• the use of mica shields or Polytrifluorochloroethylene shields to protect the glass from the corrosive action of the process fluid
• the observation of interface
• the observation of the liquid colour

This instrument consists of a metal body, machined to have an internal chamber and one or more front windows (on each side of the gauge). On each window a special high resistance plate transparent glass is applied with sealing joint and metal cover plate hold by bolts and nuts.

The chamber is connected to vessel with cross fittings and flanged, threaded or welded ends. Usually, between the instrument and its connecting ends, valves are fitted to consent shut-off piping and to disassemble the level gauge without to empty the vessel. Drain valves can also be fitted to cross fittings device.

To avoid leakage in case of glass breakage, safety ball-check device can be provided in cross-fittings or shut-off valves. This kind of indicator is suitable for water/steam. To protect glass surfaces from corrosive action of the process fluid, Transparent Level Gauges can be fitted with Mica shields or Polytrifluorochloroethilene shields. This kind of indicator is suitable for liquids colorless and very fluid.

In some case (i.e. for water / steam) the best reading is obtained by conveying upwards on the surface of separation (liquid/steam or vapor interface), a source of light, located on the back of the gauge, the rays of which are totally reflected down to the observer.

This article comes from wermac edit released