The Kowa Nitrate Process Photometer.

The Problem:

Nitrate in drinking water.

The pollution of our drinking water reserves with nitrate, which is mainly due to excessive use of fertiliser, is becoming an ever increasing challenge to all water supply companies. The public, meanwhile, is well aware that their health could be put in danger because of the nitrate in our most important foodstuff - drinking water. While the quality of the available water is decreasing there is a steadily increasing demand for higher standards. The maximum permissible level of 50 mg nitrate per litre of drinking water is a sign of this awareness.

The Answer:

The Kowa Nitrate Process Photometer.

The new nitrate process photometer from Kowa is designed to meet the requirements of the water industry. The equipment features high reliability, minimal operating costs and extreme ease of use. Its intelligent microprocessor controlled system can be adjusted to optimise it to the operating conditions. The use of this technical innovation in waterworks, purification plants etc leads to the reliable solution of a difficult measurement problem.

Operating Reliability and Costs.

The Kowa Nitrate Process Photometer measures the UV absorption of the nitrate in drinking water using a special optical technique involving a UV flash-tube and the most up-to-date opto-electronics. The interval between measurements can be programmed to be anywhere between 30 seconds and one hour. In contrast to other measuring systems which use a deuterium lamp and continuous illumination, the UV flash-tube in the Kowa instrument has a virtually unlimited life! This is a decisive advantage in terms of reliability, maintenance and consequential costs when running 24 hours a day.

User Friendly System:

• Fully automatic operation with unbelievably low maintenance.
• Calibration of the instrument using the front panel keys.
• Simple measurement of individual samples.
• Automatic zero-adjustment after each self-cleaning cycle.
• Built-in automatic cleaning system. The cleaning interval can be selected to suit the conditions at the particular site.
• The instrument has fully automatic self-monitoring for:
  • the microprocessor system.
  • component drift compensation.
  • measurement chamber becoming obscured.
  • detection of measurement errors.
  • warning and interrupt alarms in critical operating conditions. 
• Fully automatic start-up of the instrument after a power failure, in the order: initialisation, self cleaning, zero adjustment and measurement.

A Challenge for Measurement and Regulation Technology.

Water supply organisations are, more than ever, required to meet steadily increasing quality standards. In order to be able to control the nitrate levels in water, the value must be continually checked, when it is sourced, when it is treated, and when it is distributed. This requires a Nitrate Measurement System, which meets the highest specifications and which delivers precise readings with the lowest operating costs.

Intelligent Technology.

A powerful microprocessor with custom software allows menu-driven evaluation of the signals measured. Optimal adjustment of the operating conditions is facilitated by a comprehensive range of variable parameters:

• Limit warning in mg NO³ / litre.
• Linearisation of the measurement characteristics.
• Number of flashes in a measurement sequence to determine an average.
• Minimum signal level to produce a warning.
• Minimum signal level to produce an interrupt.
• Checking of the signal levels for exceptional values.
• Duration of a measurement sequence.
• Freely selectable cleaning and measurement cycles.

An integrated RS232 interface allows the instrument to be connected to another computer or evaluation system.

The Kowa Nitrate Process Photometer is therefore also suited for use as an intelligent sensory component within a control loop, automatically controlling the nitrate concentration in drinking water.

Options:

• In its standard format the instrument is not fitted with a chart recorder. Single or dual channel chart recorders are available. 
• The supply voltage (110 or 240 Volts) must be specified when ordering. It is not switchable. 
• Where the analogue output has to drive very long cables, a module can be fitted which has a 1200 Ohm drive capability.