Description of the Orifice Meter
13
This type of meter is particularly desirable in cases where a rapidly fluctuating flow is present, for the reason that because the records are separate they
cannot be confused, nor can they be obliterated by each other. Furthermore,
it is not necessary to use inks to distinguish each record, as different-colored
is the case with the combination meter. The second type, or com-
bination meter, is known
as Type C and is shown
in Fig. 1662. It has the static recorder movement mounted in the same case with the differential movement, so that both records
are made on the same chart. This meter is more
compact than the twoinstrument type and is consequently more easily
transported in the field.
It can be mounted di-
rectly on the line pipe by
use of a saddle and a short
length of 2' supporting
pipe. The advantage of having
89870 89863 both static and differential records on the same chart is obvious. Although a great many com-
panies prefer this method, just as many others prefer to have the records on separate charts of different sizes. Where both records are made on the same chart, inks of different colors are used to distinguish the records. In the measurement of gas by these meters the differential gauge charts are graduated in inches of water and the static pressure gauge charts in pounds per square inch or inches mercury vacuum. After careful consideration of all points involved in the problem of
gas measurement it was decided that only two differential ranges were necessary to cover all conditions of flow. Consequently the mercury float type differential recording gauge was developed in two ,
Gootit.
PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor