The Troemroid Scalometer
In [Figure 100] is shown the Troemroid Scalometer. This instrument is a special scale of extreme accuracy, fitted with agate bearings with screw adjustment for balancing. The beam is graduated from 0 to 2 ounces, divided into 100 parts, each division representing 1-50th of an ounce; and by using the pointer attached to the beam weight, the 1-100th part of an ounce can be weighed.
Fig. 100. The Troemroid Scalometer.
The percentage table No. II has a range from one half of 1 per cent to 30 per cent and is designed for use where extremely fine results are needed, or where a very small amount of moisture is present. Table No. III ranges from 30 per cent up to 90 per cent. These instruments are in three models as described below.
Model A. (One cylinder) ranges from 1⁄2 of 1 per cent to 30 per cent and is to be used for testing moisture contents in kiln-dried and air-dried lumber.
Model B. (Two cylinders) ranges from 1⁄2 of 1 per cent up to 90 per cent and is to be used for testing the moisture contents of kiln-dried, air-dried, and green lumber.
Model C. (One cylinder) ranges from 30 per cent to 90 per cent and is applicable to green lumber only.
Test Samples.—The green boards and all other boards intended for testing should be selected from boards of fair average quality. If air-dried, select one about half way up the height of the pile of lumber. If kiln-dried, two thirds the height of the kiln car. Do not remove the kiln car from the kiln until after the test. Three of four test pieces should be cut from near the middle of the cross-wise section of the board, and 1⁄8 to 3⁄16 inch thick. Remove the superfluous sawdust and splinters. When the test pieces are placed on the scale pan, be sure their weight is less than two ounces and more than 13⁄4 ounces. If necessary, use two or more broken pieces. It is better if the test pieces can be cut off on a fine band saw.
Weighing.—Set the base of the scale on a level surface and accurately balance the scale beam. Put the test pieces on the scale pan and note their weight on the lower edge of the beam. Set the indicator point on the horizontal bar at a number corresponding to this weight, which may be found on the cylinder at the top of the table.
Dry the test pieces on the Electric Heater ([Fig. 101]) 30 to 40 minutes, or on the engine cylinder two or three hours. Weigh them at once and note the weight. Then turn the cylinder up and at the left of it under the small pointer find the number corresponding to this weight. The percentage of moisture lost is found directly under pointer on the horizontal bar first mentioned. The lower portion on the cylinder Table No. II is an extension of the upper portion, and is manipulated in the same manner except that the bottom line of figures is used for the first weight, and the right side of cylinder for second weight. Turn the cylinder down instead of up when using it.
Examples (Test Pieces)
Model A. Table No. II, Kiln-dried or Air-dried Lumber:
If first weight is 901⁄2 and the second weight is 87, the cylinder table will show the board from which the test pieces were taken had a moisture content of 3.8 per cent.
Model B. Tables No. II and III, Air-dried (also Green and Kiln-dried) Lumber.
If the first weight on lower cylinder is 97 and the second weight is 76, the table will show 21.6 per cent of moisture.
Model C. Table III, Green Lumber:
If the first weight is 94 and the second weight is 51, the table shows 45.8 per cent of moisture.