商品介紹

Open-Air Nephelometer (NGN-2a )

The Optec NGN-2a integrating nephelometer employs a unique open-air design that allows accurate measurement of the scattering coefficient (Bscat) of ambient air. With a direct, unobstructed path from the outside air to the optical measuring chamber, modification of the temperature, relative humidity, aerosols, and gases of the sampled ambient air are minimized. The NGN-2a features low power consumption, a rugged compact design, and easy installation and operation making it ideally suited for remote monitoring. The NGN-2a is an improved version of the NGN-2.

Features Include:

  • Continuous measurement of ambient Bscat using stable and long-life silicon photodiode light detector
  • Direct and unobstructed path from outside air to the measurement chamber minimizes the modification to the temperature, relative humidity, aerosols, and gases of the sampled ambient air
  • Modular design allows easy servicing and component replacement
  • Operates in ambient conditions so that an inexpensive climate-controlled sheltering is not required. The small size with minimal support requirements allow for easy installation on towers or existing shelter walls
  • 13.8 volts at 20 watts power requirement allows for remote solar power installation
  • Internal computer monitors and controls operation, allows for flexible data-logger interface and diagnostics. Control and data logging program for Windows PC is supplied with free updates.
  • Automatic clean air and span gas calibrations at user-selected intervals
  • Three wire RS-232 at 9600 baud and two analog outputs available for data logging
  • LED lamp for very long life of approximately 50,000 hours and reduced power consumption. Effective wavelength is at 530 nm with a 40 nm band width.; Other LEDs operating at different wavelengths (470, 505 and 626nm) are available.

 

 

PM2.5 Nephelometer (NGN-3a )

The Model NGN-3a is an advanced design integrating polar Nephelometer used for the purpose of accurately measuring the scattering coefficient of dry air. The instrument uses a spiral sampler inlet to separate out particles larger than 2.5 microns to satisfy the PM2.5 standard. In addition, a heated measuring chamber dries the air sample to a preset relative humidity value. A relative humidity sensor is mounted in the sample air chamber. By measuring the scattered light over a 170 degree angle, the scattering extinction coefficient, Bscat, is reduced to units of inverse mega meters. Bmass is computed by applying a conversion factor. Bscat and/or Bmass is made available for output to analog and digital data loggers, PC computers or can be read directly from the integrated LCD display. Time, date, barometric pressure, temperature both inside and outside, RH and other important instrument settings are made available on the serial output for data capture. A unique 4-button keypad allows complete control of the NGN-3a. The keypad allows the initiation of clean air and span calibrations to be made easily. Various conversion constants and operating conditions can also be programmed with the keypad. The NGN-3a is entirely self-contained and, except for an external span gas supply, only a low voltage power source is required for operation.

Features Include:
  • Continuous accurate measurement of dry PM2.5 aerosol scattering
  • Scattering measurement is used as a surrogate for PM2.5 mass. Scattering mass efficiency is user programmable.
  • Monitoring of ambient/chamber differential temperature or chamber relative humidity to ensure drying of aerosols
  • Sample flow controlled at 7.0 l/min
  • LCD interface displays current scattering and mass value
  • Control most aspects of the instrument with the external 4-button keypad including calibration checks and many operational variables
  • RS-232 at 9600 baud and two analog outputs for data collection via data logger or computer
  • PC windows based control and data logging program is included with free updates.
  • Operates off 13.8 VDC at 3 amps. Optional power supply is available.
  • Minimal on-site servicing required with only annual maintenance recommended.
  • LED lamp for very long life of approximately 50,000 hours and reduced power consumption. Effective wavelength is at 530 nm with a 40 nm band width. Other LEDs operating at different wavelengths (470, 505 and 626nm) are available.

Visibility Transmissometer (LPV-3)

The Model LPV-3 Long Path Visibility Transmissometer consists of a constant output light source transmitter and a computer controlled photometer receiver. The irradiance from the transmitter at a wavelength of 550nm can be measured to a high degree of accuracy both day and night, and over a path length of up to 20 km. Path length is chosen based on the expected extinction values to be measured. A long path of greater than 3 km is used to measure extinction near Rayleigh and a short path of less than 3 km can be used to measure very hazy or foggy conditions.

Both the receiver and transmitter operate from a 13.8-volt battery source and use 4 and 20 watts of power respectively. The output results can be read as a voltage proportional to extinction or visual range. In addition, a separate serial data interface outputs a string of data items in ASCII format that includes all the calculated extinction values, visual range, raw instrument values and time. The units can operate for long periods of time unattended in a continuous or timed cycle mode. The self-resetting and backup systems ensure continued operation even after power blackouts or computer lockup. Both units can be synchronized, programmed and calibrated at the home station and installed in the field ready for operation.