Air-flow transducers Measure air flow and velocity elec tronically with 20 selectable ranges from 0-12 000 ft/min and ± 2 % fullscale accuracy. The transducers are compatible with computers, data loggers, and air monitoring systems. Sierra Instruments 113
TOX Plus TRIHALOMETHANES
Emission monitor
Instrument uses glass fiber optic cables around the outside of smokestacks to measure opacity. It has a set-point alarm, a 1 -6 min integrator, automatic exit correction, and an air-operated lens cleaning unit. The opacity output is displayed on a strip chart recorder or data logger. Datatest 114 Radiometer
Designed for use in salt gradient solar ponds, this radiometer measures the energy interchange between the vari ous thermal gradient levels. The re motely switchable modes of operation enable the instrument to measure ra diant energy in the upward or down ward directions, or the net balance. The unit has a flat spectral response from 0.3-2.8 μιτι and is linear from 0-100 °C. Hollis Geosystems 115
The New Model 610 — a screening machine. The New Model 610 TOX Analyzer is a rapidfire screening analyzer for organic halogens — plus, it can be equipped to perform the EPA's specified procedure for analysis of trihalomethanes. 1 The screening approach can save the cost (hundreds of dollars) of detailed specific ana lyses on every single sample. Surrogate tests. Purgeable Organic Halogen (POX) tests may be regarded as a surro gate for certain highly specific measurements, including those for trihalo methanes. Non-purgeable Organic Halogens (NPOX) can be used as a surrogate test for pesticides, PCBs, and certain other pollutants in water. Both POX and NPOX comprise TOX, and are separately measured by the Model 610. A surrogate test can be used to determine whether more specific testing is warranted. In ruling out those samples where contami nants of interest are clearly not present, the Model 610 can save a tremen dous amount of money. And where trihalomethanes are not ruled out — the 610 has the capability for this key specific analysis. The combination, T O X plus trihalomethanes, makes excellent sense. Those " O t h e r " Contaminants. Chlorine may react with natural organic compounds present in wafer to form chlorinated humics of unknown structure. These com pounds can be detected as a group by the Model 610. This feature is especially useful in making before-and-after evaluations of filtration and other purification techniques. Buy one. There's nothing like it for speed. Sample goes in, result comes out. Period.-Write for a detailed brochure, or call (713) 693-1711. '"The analysis of trihalomethanes in finished water by the purge trap methods," U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory,Cincinnati,Ohio. September9,1977.
Power supply Device delivers a dc voltage to a ther mal conductivity detector or a gas density balance. Two models are available: the 40-200 hot-wire supply and the 40-400 thermistor supply. The 40-200 uses thumbwheel switches to set current and makes use of a bar readout. The 40-400 uses current control and meter readout. Both models have solid-state components. G O W - M A C Instrument 116 Thermometer calibration cells
Fixed-point cells use the thermometric freezing points of high-purity metals (99.999%) for precise meteorological calibration of thermometers. The metal is contained in a graphite cru cible that is enclosed in a quartz en velope filled with inert gas at a pres sure of 1 standard atm at the freezing temperature. Freezing-point cells for the following metals are available: in dium, tin, lead, zinc, aluminum, and silver. Yellow Springs Instrument 117
The Model 610. For TOX, POX, NPOX and, as an accessory capability, Trihalomethanes. An unbeatable combination.
O . I . CORPORATION P.O. Box 2980
College Station, Texas 77840
(713)693-1711
CIRCLE 7 ON READER SERVICE CARD Environ. Sci. Technol., Vol. 16, No. 11, 1982
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