Microprocessor Based Turbidity Meter Model ANALITE 160

   The ANALITE 160 turbidity meter is the latest of our range of turbidity measurement instruments. It is designed to operate with either an ANALITE retro-scatter (180°) probe or an ANALITE 90° probe - to be specified at time of order. The ANALITE 160 turbidity meter allows the user to set up measurement parameters through a user friendly menu system displayed on the in-built 2 line alphanumeric display. Measurements can be read directly from the display at any time or downloaded to a computer/printer through the optional RS232 output at user selectable periodic intervals. The NEP160 will power up automatically to its last settings whenever external power is applied making it ideal for logging applications when using the analogue output or optional RS232 port.

Turbidity Meter (WQ770)

   The Global Turbidity Sensor is a highly accurate submersible instrument for in-situ environmental or process monitoring.  Applications include; water quality testing and management, river monitoring, stream measurement, reservoir water quality testing, groundwater measuring, water and wastewater treatment, effluent, and industrial control.

Method:

   In accordance with USEPA Method 180.1 for turbidity measurement the sensor is a 90 degree scatter nephelometer where a focused beam is directed into the monitored water.  The light beam reflects off particles in the water, and the resultant light intensity is measured by a photodetector positioned at 90 degrees to the light beam.  The detected light intensity is directly proportional to the turbidity of the water.  The turbidity sensor utilizes a second light detector to correct for light intensity variations, color changes, and minor lens fouling.

Turbidity Meter:

   The Global Water Turbidity Meter combines the turbidity sensor with a handheld meter that has a six digit LED screen, 4-button control panel, and an internal 9V battery.  The handheld portable water meter can be used for enivronmental or process sites that do not require permanent monitoring.  The meter will display readings directly in either nephelometric turbidity units (NTU) or parts per million (PPM). It also includes an automatic shutoff feature to conserve battery power.

Range: Sensor=0-50 NTU and 0-1000 NTU; Meter=0-50 NTU or 0-1000 NTU

Accuracy: + 5% of full scale

Meter Resolution: 12 bit

Method: Nephelometer with correction

Operating Voltage: 10-36 VDC @ 40 MS (Sensor); Internal 9VDC battery (Meter)

Current Draw: 31 mA plus sensor output (WQ710)

Warm-up Time: 10 seconds minimum (Sensor)

Operating Temperature: -40° to +50°C

Materials: Black anodized aluminum, stainless steel, delrin, Sapphire optical windows, Polyurethane jacketed cable.

Pressure: 0-50 psi

Light Source: pulsed LED

Cable Length: Sensor=25' standard (optional to 500'); Meter=10' standard (optional to 100')

Size: Body= 1 1/2"D x 8.5"L  Sensor Shield= 1 1/2" x 2" Overall Length: 9"

Weight: 2 lbs.

Series A15/76 Turbidity Monitor

  Turbidity is a general indicator of the optical clarity of water and is defined as the amount of light scattered from particles in solution. In practice, a light beam is directed into a water sample and a photo detector measures the light scattered at 90° to the incident light beam. While other scatter angles are possible, the 90° measurement angle has become the standard for turbidity measurement in most water systems. It is used as a relative indicator of the amount of suspended solids in solution and is measured in virtually all drinking water systems. It is also used in industrial water treatment systems as an indicator of product water quality.

   Model A15/79 Turbidity Monitor is designed to meet the needs of both municipal drinking water systems and industrial water treatment for reliable, low range turbidity measurement. Using an infrared light source and a 90° scatter measurement, the system provides high sensitivity measurement with unmatched zero stability. Turbidity measurements down to 0.001 NTU or as high as 4000 NTU can be measured with the same monitor, eliminating the need for separate high and low range instruments.

   The turbidity sensor used in the A15/76 is a planer sensor with the light source and photo detector mounted on a flat face. Lenses in front of the light source direct the beam of light at a 45° angle into the sample. Another lens in front of the photodetector collects the 90° scattered light and directs it to the detector. The signal generated by the detector is amplified inside the sensor for transmission to the display unit. Periodic pulsing of the light source allows the sensor zero to be adjusted automatically for improved stability in low range applications.

  Turbidity sensors are available for measurement in a pressurized flowcell or for direct submersion in open tanks. The flowcell is required for very low measurements (0-4 NTU), while the submersion unit may be used for higher turbidity applications such as wastewater effluent or raw water.

   Air bubbles are a common problem in many turbidity systems. ATI's turbidity sensor is designed to operate under pressure to eliminate the sample degassing that often causes air bubble errors. Sample pressure in not dropped until the sample exits the measuring chamber, resulting in more reliable measurements. The turbidity electronics unit is a compact panel mount instrument providing an LCD display of turbidity value, as well as indication of alarm status and instrument diagnostics. For stand alone applications, a NEMA 4X wall mount enclosure is available.

   The monitor provides display of turbidity over a variety of operating ranges. The minimum display range of 0-4 NTU provides resolution down to 0.001 NTU and is suitable for almost any final filter monitoring application. Range of 0-40 or 0-400 NTU are available for raw water or clarifier effluent monitoring. A0-4000 NTU range may be used for very high turbidity applications such as river water monitoring. In addition, the monitor may be calibrated fur suspended solids measurements, with range from 0-10 mg/l up to 0-10,000 ml/l.

   Standard turbidity systems provide a variety of outputs. Two programmable alarms with SPDT alarm relays are included, as well as an isolated 4-20 mA output. The analog output may be programmed for full scale outputs as low as 0-0.2 NTU and can inverted if desired. Alarm and output information can be displayed on the LCD at the push of a button and the alarm relays can be activated manually for test purposes when needed.

   A15/76 monitors also provide sensor diagnostic functions to warn of conditions that cause inaccurate or invalid readings. The sensor is continuously monitored for optical fouling and will display an alarm message when the sensor requires cleaning. In addition, the sensor will detect the lack of water in the flowcell and provide a "dry cell" when an air interface is detected. These alarm conditions will cause a third alarm relay to activate, which can be used to indicate these conditions remotely.

   Because turbidity measurement is often required in wastewater effluents and other applications where sensor fouling can be a major problem, ATI offers a special turbidity unit, the B15/76 system, that uses an "air blast" sensor cleaning system that automatically cleans the sensor as often as necessary to maintain reliable measurements. This system is used only for submersion applications only, and all air supply components required for the cleaning process are supplied in the NEMA 4X monitor package.