24 
BULLETIN 1375, U. S. DEPARTMENT OF AGRICULTURE 
Table 2. — Variation in the gas pressure in the supply line on a moisture tester 
when a varying number of gas burners are in operation 
Number of burners In operation 
Gas 
pressure 
on 
supply- 
line— 
inches 
head of 
water 
Number of burners in operation 
Gas 
pressure 
on 
supply 
line — 
inches 
head of 
water 
-. . 
4.6 
4.0 
3.7 
3.2 
2.6 
7 
2 3 
1 
9_ 
2.0 
2 
10 
1.8 
4 
12 
1.2 
6 _. . 
Table 2 gives the results of tests of the gas pressures on the supply 
line of a 12-compartment moisture tester with varying numbers of 
burners in operation. 
Other things being equal, a low gas pressure will result in a longer 
heating time and in a loAver moisture test, and a high gas pressure 
will result in a shorter heating time and in a higher moisture test. 
From tests made, data for which are given in Table 3 and illustrated 
5 Minutes 
_.-. _____,,„- ___«„ 10.57, Moisture 
GAS PRESSURE. ERROR , __ * 
3.6 INCHES 
Correct Heating rime 
and 
Correct Moisture Test 
3.2 INCHES 
2.2 INCHES 
1.2 INCHES 
STANDARD 
METHOD j " ^^^^^^^^^^^^g 
with gas I correct ■■■HIIEPmiSfll^^H^^HH— 
REGULATOR L TEST _ .^■■^■■■(■(■■■■■■^■^^^^^■■H 
P;*;;^ Heating Time Q| Moisture 
Fig. 19. — Effect of gas pressure on the heating time and the moisture test result 
in Figure 19, it was found that when the burners of the compart- 
ments were set to give the correct heating time at the minimum gas 
pressure on the supply line, which in this case was 1.2 inches, the 
heating time was reduced and the moisture test result was increased 
very appreciably when the gas pressure was increased. It will be 
noted that the moisture test result increased in direct proportion to 
the increase in the gas pressure. 
