DSM liquid is a mix of 50% glycerin and 50% water. This mix have a freezing temperature of about -23°C.

DSM liquid is de-aired at factory and it is supplied sealed in special tank. However in the DSM reference gauge there is a high sensitive sensor which is able to monitor the weight of the liquid within the reservoir. In the case of the air bubbles come over decreasing the level of the liquid in the reservoir the sensor measures this change. Thus air bubbles are not usually a problem.

The arms of the spider only keep the magnet in place while grouting, but the grout couples the magnet to the surroundig soil. Grout mix shall be controlled (ratio water/cement) during grouting operation according to the soil application.

The DSM pressure gauges are vented to atmosphere by special electric vented cable. Therefore the DSM system is not affected by changes in atmospheric pressure.

The DSM settlement system consists of four main components: a string of DSM pressure gauges, a liquid filled tubes, electric cables and a DSM reference gauge with reservoir of liquid. The DSM pressure gauges are embedded in the soil and by tubing connected to the DSM reference gauge which shall be located at higher elevation on a stable ground, away from the construction activities. The DSM pressure gauges measure the pressure created by the liquid column in the tubing. The height of the liquid column is equal to the difference in elevation between the DSM pressure gauges and the DSM reference gauge. Electric cables provide connection to ADK-10 data acquisition unit for automatic monitoring.

The main factors which influence the anchor measurements are: - axial misalignment of the jack, - difference in diameter between the jack and the load cell. These factors cause bending of the bearing plate between the load cell and the jack and affects the response of the cell. To minimise this effect use the genuine distribution plate which loads properly the sensitive upper ring of the load cell.

Yes, each vibrating wire piezometer is equipped with a built-in NTC thermistor YSI 44005 type (3000 Ohm at 25°C). Thermistor is not a option for vibrating wire instruments and therefore there is not additional cost for it.

Yes, we sell a kit which includes instructions, probe, weights, rexin, and any other parts.

A plasma surge arrestor is wired in parallel with the coil (which is used to pluck the wire). The nominal impulse discharge current 8-20 microsec interval is 10 KA. Impulse spark-over voltage at 1Kv/ microsec: 700 V.

HAE filters are normally used to monitor pore pressure in the clay core dams and saturated low permeability soils. "High air entry" means high-resistance to air entry when the filter is saturated. The surface tension of the water in the very fine pores of the filter prevents entry of air. The HAE filters must be saturated before installation by means of the saturation device.

The measurement of total pressure in geomechanics, even if is one of the most interesting parameters for the designer, is generally considered not reliable. Case histories report more nonsuccessful examples than for all the other types of measurements. Theoretical studies made by many researches have highlighted the critical parameters in the design and manufacturing of pressure cells. If the instruments are accurately designed and manufactured and the choice of the model has been done properly, the problem becomes how to use the cell. In the paper presented by Mr. D. Bruzzi and Mr. A. Zattoni (SISGEO) and Mr. G. Pezzetti (ISMES) at 5TH International Simposium FMGM/99 in Singapore, the authors discuss the main issues related both to laboratory calibration and field installation problems, and a practical approach is presented in order to improve the quality of the results. The conclusion is that pressure cells provide relative measures that can become absolute by using simple and practical rules deriving from a good knowledge of the basic problems related to design, manufacturing and installation of total pressure cells. For a complete view of this paper, click here to download the .pdf file.

Yes it is. The pump is filled at factory under vacuum with de-aired oil. For normal use within concrete the oil inside the pump is enough to repressurize 50 pcs. of NATM pressure cells. The oil we use is Edwards Ultra-grade 19 type for vacuum-pump use .

NATM pressure cells are normally used to measure tangential and radial stresses in concrete tunnel lining. They are embedded in concrete and after curing the cell shall be repressurized to mantain the intimate contact between the pessure pad and the surrounding material.

Borehole should be drilled as close to the vertical as possible, however 2/3 degrees from vertical are normally accepted in specifications.

A good practice for the inclinometer users is to follow these simple recommendations: - when you connect the inclinometer operating cable to the probe, avoid overtightening the nut, since this will flatten the O-ring and reduce its effectiveness; - use a pulley assembly. It protects the inclinometer operating cable and provides a good reference index; - when very high precision is expected, it may be useful to periodically record the date and the precise length of your inclinometer operating cable; - perform regular maintenance.