Air-Purging System

TM 5-6640-213-14

(e) and (f) for the alarm set

(g)

Repeat

steps

(d),

point.

The air-purging system is located

(5) Air-Purging System.

It consists of a grill and exhaust

in a cabinet opposite the sink.

through wall mounted louver assembly and out of the laboratory at the

rate of 600 cubic feet per minute (cfm).

NOTE

The

air-purging system is also activated

when

the main power switch is turned on

and

it can be operated manually by the

fan

switch beneath the light switch.

Test

Equipment.

(1)

Double

Beam

Balance.

The double beam balance (NSN 6670-00-

(a) Description.

436-9857) is supplied for weighing chemicals that are to be used in

various testing procedures.

The upper beam is graduated from O to 10

The lower beam is graduated from O to

grams in O.1-gram divisions.

Two removable, 6-inch (15.2 cm) dia-

200 grams in 10-gram divisions.

The capa-

meter, stainless steel pans are supplied with the balance.

city of the balance without the use of loose weights is 210 grams.

Since the capacity of the balance exceeds the beam capacity, the use

of additional loose weights is necessary to take advantage of the

A set of 12 brass, tall-form, loose weights (NSN 6670-

full capacity.

00-803-9680) is included with the laboratory equipment for use with

The weights are positioned in a vinyl plastic block and

the balance.

they range in size from 1 to 1,000 grams.

(b)

Operating

Procedures.

Set each poise at the zero mark.

Always check balance zero before each use. If

the instrument does not balance at exactly zero, make the necessary

corrections with the two knurled nuts on the front of the beam.

When the balance" has been restored, lock the nuts against each other.

Place the specimen to be weighed on the left

platform

the

balance.

Move the lower poise to the right until the

Move

first notch is reached; this causes the right platform to drop.

the poise back one notch; this should cause the right platform to rise

again.

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