CONCRETE DAM INSTRUMENTS

1. IN-PLACE INCLAINO METER:

The In Place Inclinometer (IPI) is designed for near vertical borehole applications, the principal operation and data obtained are similar to the traversing type inclinometer systems such as the portable Digital Bluetooth Inclinometer systems. Typical applications of the IPI system include the monitoring of landslide areas, stability of natural slopes and Dams, railroads, highways, landslide areas and early warning of a pending slope failure, ground movements due to tunnel construction and excavation as well as monitoring deformations of embankments and retaining walls.

The system utilizes a fixed string of inclinometer probes separated by rigid gauge tubing, the main advantages include rapid automatic data logging and real-time monitoring. The IPI sensor incorporates a MEMS accelerometer making the instrument virtually shock proof, giving a high degree of repeatability and accuracy. The sensor incorporates an on-board microprocessor which performs an automatic temperature compensation of the tilt (g) data. The sensor is a very low power, low EMC device which conforms to the specifications laid down under EN50121 1-4, making it particularly suitable for work on or adjacent to railway lines and in tunnels

2. EXTENSOMETERS:

Specifically designed for the highly accurate measurement of strain and deflection, these instruments provide valuable testing information. Extensometers measure strain, which is calculated as the change in length of a specimen divided by the original length (gauge length) of the specimen. Products include extensometers for elongations up to 50% and gage lengths up to 2 inches, extensometers for high temperature or longer gage lengths, extensometers for high elongation, deflect meters and compress meters, bolt extensometers, strain gage extensometers, and video extensometers

An extensometer is a device that is used to measure changes in the length of an object. It is useful for stress-strain measurements and tensile tests. Its name comes from "extension-meter". It was invented by Dr. Charles Huston who described it in an article in the Journal of the Franklin Institute in 1879. Huston later gave the rights to Fairbanks & Ewing, a major manufacturer of testing machines and scales

3. PENDULUM:

A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released, the restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum and also on the amplitude of the oscillation. However, if the amplitude is small, the period is almost independent of the amplitude.

From its discovery in around 1602 by Galileo Galilei, the regular motion of pendulums was used for timekeeping, and was the world's most accurate timekeeping technology until the 1930s. Pendulums are used to regulate pendulum clocks, and are used in scientific instruments such as accelerometers and seismometers. Historically they were used as gravimeters to measure the acceleration of gravity in geophysical surveys, and even as a standard of length. The word 'pendulum' is new Latin, from the Latin pendulums, meaning 'hanging'.

The simple gravity pendulum is an idealized mathematical model of a pendulum. This is a weight (or bob) on the end of a massless cord suspended from a pivot, without friction. When given an initial push, it will swing back and forth at a constant amplitude. Real pendulums are subject to friction and air drag, so the amplitude of their swings declines.

4. MULTICHANAL DATA LOGER:

Technically speaking, a data logger is any device that can be used to store data. This includes many data acquisition devices such as plug-in boards or serial communication systems which use a computer as a real time data recording system. However, most instrument manufacturers consider a data logger a stand-alone device that can read various types of electrical signals and store the data in internal memory for later download to a computer.
The advantage of data loggers is that they can operate independently of a computer, unlike many other types of data acquisition devices. Data loggers are available in various shapes and sizes. The range includes simple economical single channel fixed function loggers to more powerful programmable devices capable of handling hundreds of inputs. 

5. PIZOMETER:

The Standard Piezometer is designed to measure fluid pressures such as ground water elevations and pore pressures when buried directly in embankments, fills, etc. Also for installation inside boreholes, observation wells and standard (>19 mm diameter) piezometer riser pipe. The Model 4500SH is designed with a heavy duty housing for pressures that exceed 3 MPa. The Model 4500AL is designed for low-pressure ranges. The vented version (ALV) provides automatic compensation for barometric pressure changes. Thermistors are included to measure temperatures.

6. LOAD CELL:

A load cell is a transducer that is used to convert a force into an electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge measures the deformation (strain) as an electrical signal, because the strain changes the effective electrical resistance of the wire. A load cell usually consists of four strain gauges in a Wheatstone bridge configuration. Load cells of one strain gauge (quarter bridge) or two strain gauges (half bridge) are also available. The electrical signal output is typically in the order of a few millivolts and requires amplification by an instrumentation amplifier before it can be used. The output of the transducer can be scaled to calculate the force applied to the transducer.

The various types of load cells that exist include Hydraulic load cells, Pneumatic load cells and Strain gauge load cells.

7. TILT METER:

APPLICATIONS:

The portable tiltmeter is used to monitor changes in the inclination of a structure. Tiltmeter data can provide an accurate history of movement of a structure and early warning of potential structural damage. Typical applications include:

·         Monitoring rotation caused by mining, tunneling, soil compaction, or excavation.

• Monitoring rotation of concrete dams and retaining walls.

COMPONENTS:

The tiltmeter system includes a number of tilt plates, the portable tiltmeter, and a readout unit. Tilt plates are available in ceramic or bronze. Both are dimensionally stable and weather resistant. Protective covers are available for bronze tilt plates.

The portable tiltmeter uses a force-balanced servo-accelerometer to measure inclination. The accelerometer is housed in a rugged frame with machined surfaces that facilitate accurate positioning on the tilt plate. The bottom surface is used with horizontally-mounted tilt plates and the side surfaces are used with vertically-mounted tilt plates.

OPERATION;

Tilt plates are mounted on the structure in specified locations. They are typically bonded to the structure, but may also be screwed to the surface.

To obtain tilt readings, the operator connects the tiltmeter to the readout unit, positions the tiltmeter on the tilt plate, and notes the displayed reading. The operator then rotates the tiltmeter 180 degrees and obtains a second reading. Later, the two readings are averaged to cancel sensor offset. Changes in tilt are found by comparing the current reading to the initial reading.

8. CRACK METERS:

The Crack meter is intended to measure movement across surface cracks and joints. It is installed by grouting, bolting, or bonding two threaded anchors (with ball joints) on opposite sides of the crack and then attaching the ends of the gage to the anchors.

9. Embedment Joint meters:

The Model 4400 Embedment Joint meter is designed for use across construction joints, such as those between adjacent blocks in a concrete dam. It is normally embedded across the joint to monitor the expansion or contraction of the joint. The use of internal universal joints allows for a degree of shearing motion.

10. Embedment Strain Gauge:

The Vibrating Wire Embedment Strain Gauge is used for measuring strain in concrete structures and is suitable for direct burial. Also used in pile tests, load bearing concrete beams and columns, tunnel segments and concrete foundations.

The Vibrating Wire Embedment Strain Gauge is used for measuring strain in mass concrete.

The 150mm long gauge, which is made from stainless steel, may be pre-attached to rebar or by attachment to a 2, 3 or 4 directional rosette, thereby measuring strain in several directions.The gauge comprises a sealed tube containing a wire held in tension between two circular stainless steel pads, one at each end.Deformation to these pads alters the tension of the wire and the resulting readings are used to measure strain. The changes in strain are monitored by the coil assembly mounted on the gauge. The gauges can also read temperature if required.

11. Temperature Gauges:

With substantial industrial experience, we have emerged as a renowned manufacturer and exporter of temperature gauges. Our range includes bimetal temperature gauge, mercury gas filled temperature gauge capillary type and temperature recorder. Easy to mount on stem, panel and surface mercury gas filled temperature gauge capillary type is widely used for accurate measurement of temperature. Our temperature recorder has gained wide appreciation for its ability to efficiently function in complex temperature conditions.

TYPES OF TEMPRATURE GAGUES:

                        i.            BIMETAL TEMPRATURE GAUGE:

We are one of the reputed manufacturers and exporters of Bimetal Temperature Gauge that finds wide application in food and beverage industries. Highly reliable the rugged bimetal helix is properly heated and coated with viscous silicon to improve temperature transmission and minimize pointer oscillation. A popular temperature measuring instrument, it finds wide application in hot water boiler, power plant, domestic & industrial heating system and pharmaceutical industry

                        ii.            TEMPERATURE GAUGE STEM TYPE:

We are engaged in offering mercury gas filled Temperature Gauge Stem Type that has gained wide appreciation for accurate temperature measurement. This gauge is made using bulb, transmitting capillary and flat bourdon tube that are pressure filled with Mercury. This economical, rugged and reliable temperature measuring instruments is available in 80, 100, 150, 200, 250, 300 mm sizes.  These gauges can be easily mounted on stem, panel and surface.

                          iii.            TEMPRATURE GAUGE CAPILLARY TYPE:

Meeting the demands of several industries, we offer mercury gas filled Temperature Gauge Capillary Type. Fabricated using quality raw material, it is widely used for accurate measurement of temperature.  These gauges can be easily mounted on stem, panel and surface. Available in various sizes this capillary type gauge is widely appreciated for accuracy and durability.

12. EARTH PRESURE CELLS:

The Earth Pressure Cells are designed to measure total pressure in earth fills and embankments. All cells consist of two circular stainless steel plates welded together around their periphery and spaced apart by a narrow cavity filled with de-aired oil. Changing earth pressure squeezes the two plates together causing a corresponding increase of fluid pressure inside the cell. A vibrating wire pressure transducer converts this pressure into an electrical signal which is transmitted to the readout location.