Switches Indicators & Gauges

Hydrostatic Pressure

Hydrostatic pressure is the pressure at any given point in a static fluid. Pressure in open conditions (e.g. the ocean, the atmosphere, a pond) can be approximated as the pressure in static conditions, since the motion of currents or waves create only negligible changes in pressure. It is the same at any given point because otherwise the fluid would move in the direction of the resulting force.

According to the principles of equilibrium, the pressure of a liquid at rest is isotropic, meaning it acts with equal magnitude in all directions. If a point in the fluid is thought of as an infinitesimally small cube, the pressure of every side of this unit of fluid must be equal. This characteristic allows fluid to transmit force through the length of pipes (a closed condition).

Hydrostatic pressure is useful for determining the levels of liquid in a tank, among other things, using devices such as a hydrostatic tank gauge.

Hydrostatic Bubbler

Semrad Pty Ltd offers a range of industrial level gauges, sensors, switches and transmitters. Their WaterLOG® H-3531 FlashLite™ is a NIST traceable pressure sensor. It combines low cost with high accuracy, as it can directly measure dry gas with accuracy better than 0.02% FSO. It comes with built-in temperature compensation, with an operating range between -40° and +60°C.

This non-submersible pressure sensor has an easy to use Simple RS-232 Menu Interface, and a non-conductive and corrosion proof enclosure. Its SDI-12 output provides measurement data in engineering units (e.g. feet or meters), it is easy to use with the H-355 Gas Purge System and is compatible with the RS-232 Data Logger. It also features extended SDI-12 command for setting the stage to the correct water elevation or pressure. It operates on low currents and deviates less than 0.02% from a staight line referenced to end points.

Data Loggers

Data loggers are devices that record the measurements of sensors, whether they are internal (as in combination loggers and sensors) or external. They can be designed for general purpose applications then programmed to specific parameters, or be very specific devices designed for only one application with no changeable parameters. Electronic data loggers replaced chart recorders, and have the benefit of being able to automatically detect data 24 hours a day. This means that during the period specified to be monitored, a comprehensive and accurate record of the conditions being recorded is available.

Data loggers can interface with a remote computer that has software to analyse the data, or can be self-contained with a local interface with keypad and screen. They are designed to be extremely durable and reliable, as the loggers are often left in harsh and remote conditions for long periods of time. Any failure to record data could potentially compromise the record. Data loggers can be used in a whole range of applications from environmental conditions, weather station recording, road traffic counting, process monitoring and tank levels.

WATERLOG® H-350-XL and H-350

The Model H-350-XL is a microprocessor controlled pressure sensor and data logger designed for remote operation, while the Model H-350 is designed for use in the laboratory. They can be interfaced with data loggers, chart recorders, GOES transmitters, remote displays and telemetry systems.

The combined loggers and sensors replace mercury manometers, are compatible with SDI-12 and RS-232 data loggers, are seared in a corrosion-resistant nonconductive enclosure, and operate in temperatures between -40° and 60° C. They also come with built-in temperature compensation and auto-zero functions, and data logging capability using a non volatile internal storage.

These WATERLOG® combined loggers and sensors are available from Semrad’s environmental water products division, as well as data collection platforms, sensors, gas bubbler systems, communication products and rain gauges.