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* Photos, Plots, and Descriptions Relating to *
* Betatronics Sensors using Dallas 1-Wire® Components. *
" We manufacture and assemble useful sensors with 1-Wire® devices. "

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* Heating System Measurements *


These measurements are from a gas fired forced air heating system using Betatronics packaged sensors. Input rating is 125,000 BTU/HR. Bonnet capacity 100,000. The sensors are used for monitoring only, no control function.

There is an outside temperature sensor, a flame sensor, a plenum sensor, a sensor in front of a basement ceiling register in the main duct about 42 feet from the furnace, and a sensor adjacent to the living room thermostat. Duct lengths to the living room are more in the 15 to 25 foot range. The thermostat is on a side interior wall of the living room. This location does not have a very thermally conductive path to an outside wall.

One data plot has a whole house electric power measurement. This power measurement has a resolution of 1 second. The middle of the night was selected because there is the least random electrical activity. The goal was to find a time period where the furnace motor on and off points could be seen clearly in the whole house power measurement. The power measurement was from a non-1-wire system, but the two separate time clocks were synchronized. Time resolution for the 1-Wire sensors was 2 seconds.

This is a small sampling of data to illustrate some measurements that can be made with the Betatronics sensors.

The first flame measurements we made were made with the Dallas chip simply soldered to the end of the cable and totally exposed. In the position used and after about a year the vinyl cable was quite cooked. Really it was too close to the flame. The same information can be obtained by being a little further away. Then we made a suitable mount for a BTW1-22 and this has the chip at a lower temperature point. The curves from the two sensors are quite similiar. A comparison is shown below.

Betatronics can be classified as both a manufacturer and vendor of assemblies using Dallas 1-Wire devices. A major application area is in industrial manufacturing plants, bearing, motor, room temperature at different elevations, ground temperature, fluid temperature from the outside of pipes, and other monitoring functions.

P1 --- Plot 110423-0326-0338-Flame-Plenum-640.

Displayed are data plots of the heating portion of the cycle. Initially the flame sensor has a very rapid temperature rate of rise. Then temperature drops some because the cast iron burner and heat exchanger are cold. A minimum is reached, and as the burner and other surrounding metal heats the temperature starts to rise again. This continues until the flame is turned off.

Flame on-off timing is controlled by the living room thermostat. About 14 inches above the flame is a local thermostat sensing the bonnet air temperature and this controls the fan motor. Time from flame on to blower on in this plot is 1.848 minutes (110 seconds).

The plenum temperature sensor is about 52 inches above the flame. You see only a small rise in the plenum temperature until the blower turns on. Then a rapid rise in temperature.

Plenum peak temperature is slightly later than flame off because of stored thermal energy in the burner and heat exchanger.

P2 --- Plot 110423-0350-0400-Flame-Plenum-640.

These plots are the same as P1, except the time range was increased to 1/2 hour to display two heat cycles. The first cycle here is the same as in P1.

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P3 ---

More later.


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