Solar-powered thermometer replaces mercury-in-glass models

Solar-powered thermometer replaces mercury-in-glass models
Solar-powered digital thermometer from Palmer Instruments

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Solar-powered digital thermometers from Palmer Instruments are a direct replacement for industrial mercury-in-glass (MIG) and bimetal thermometers.

“It doesn’t require any batteries. It doesn’t require any line power,” says Tadd Ayers, product engineer for Palmer Wahl Instruments. “You just have to have 10 lumens of light and the unit will come to life and function.”

Completely mercury free, the environmentally friendly thermometer with high-impact ABS case is available in a base model (PST500) or with 4-20 mA transmitter capability (PST550) for connection to a remotely installed controller or recorder. The transmitter has a temperature range of -58 to 302 degrees F and ambient operating temperature of -15 to 185 degrees F. Maximum load resistance is 775 watts with a 24-volt DC supply.

The thermometer features an easy-to-read 1/2-inch LCD screen that can be set for C (Celsius) or F (Fahrenheit) readings. An adjustable angle fitting enables the casing to rotate 180 degrees for optimal viewing and the stem to be positioned in 10-degree increments.

“They were really designed for the HVAC market, but they have application potential anywhere there’s mercury-in-glass,” Ayers says.

Suitable for indoor and outdoor use, including 100 percent humidity, rain covers are available for full-time outdoor installation.

“Another thing that makes these unique is you can get one unit that will take you from -50 degrees F all the way up to 300 degrees F,” Ayers says. “Previously you had to have multiple thermometers for that range.” The thermometers, which update every 10 seconds, have an ambient temperature range of -30 to 140 degrees F with 0 temperature error. They require no maintenance or cost to operate.

“It’s easy to install,” Ayers says. “It basically takes care of itself. There’s no power you have to run to it and no batteries you have to change. It also has full conformance with federal specification GG-T-321D.”

Temperature-sensing cast aluminum stem options include industrial, bimetallic and air duct. 800/421-2853;


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