Dwyer 1212 User Manual [en, es]

Slack Tube®Manometers

Instructions and Operation

Slack Tube®Manometer rolled up for easy handling
and storage.

®

Dwyer

Slack Tube®Manometers are as accurate

as the finest laboratory “U” gages - yet they are
made to roll up compactly for easy carrying and to
withstand rough usage.
Simply unroll the Dwyer® Slack Tube®Manometer
and set up to read static pressure, vacuum, or
differential pressure. Magnetic clips hold it firmly to
any steel surface or hang it on a nail. Turn
connectors one revolution to open. When the
pressure is imposed, add the number of inches one
column travels up to the number of inches the other
column travels down. When reading is completed
turn connectors to seal columns, roll up
manometer into compact coil and tuck it away in its
circular metal case or a tool box. No fluid lost. No
loose caps or inserts to lose.
Dwyer® Slack Tube®Manometers cover a wide
range of pressure readings from 4-0-4 inches up to
60-0-60 inches. Use them in determining velocity
and static pressures, for leakage, fan and blower
tests, calibrating control devices, checking gas
pressure and many other applications.

Bulletin D-20

All models have flexible vinyl-plastic columns
and flexible spring steel scale calibrated in
inches of water using water, and inches of
mercury using mercury. Scale is center­mounted between columns to eliminate parallax
error and has a full 2-inch sliding zero
adjustment.

All Dwyer® Slack Tube®Manometers feature
exclusive molded nylon tubing connector
assemblies with rapid shutoff design in an
unbreakable molded top (see picture, page 2).
One turn counter clockwise and the instrument
is ready for use. Another turn seals the tubes
completely. Molded all-nylon construction
makes this assembly corrosion-proof leakproof
and practically unbreakable. Tubing connectors
extend horizontally allowing 360° freedom.
Tubes will not bend or pinch off.

All models have over pressure safety traps in
the top of both columns to prevent loss of fluid
due to over range pressures or surges in
pressure.

Slack Tube®Manometers are suitable for total
pressures to 50 psi and vacuum not exceeding
20˝ Hg. (10˝ Hg absolute). Can not be used with

0.826 sp. gr. red gage fluid; use only water or
mercury.

STANDARD ACCESSORIES

Standard Accessories are metal carrying case,
magnetic mounting clips, two rapid shutoff type
molding nylon rubber tubing connectors and one
bottle of fluorescein green color concentrate
with wetting agent. Mercury is not included but
will be furnished at added cost when specified.

OPTIONAL ACCESSORIES

Optional Accessories are available in a wide
range and are in misc. section.

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com

FILLING

Using 1 quart distilled water, add 1 oz bottle of A­126 Fluorescein green color concentrate.
Remove a tubing connector from the manometer
and pour fluid in to mid-point level. Shake to
remove air bubbles and slide scale so zero mark
is in line with the meniscus of the two fluid
columns.
For readings in inches of mercury, fill with 13.6
sp. gr. triple distilled mercury. When used with
mercury, some discoloration of the vinyl tubing
will normally occur.

READING

Connect the manometer to the source of
pressure, vacuum or differential pressure. When
the pressure is imposed add the number of
inches one column travels up to the amount the
other column travels down to obtain the pressure
reading. If the reading is desired in other units
the conversion chart may be used.

Should one column travel further than the other
column, due to minor variations in the tube I.D. or
to pressure imposed, the accuracy of the
pressure reading thus obtained is not impaired.
The U-tube manometer is a primary measuring
device indicating pressure by the difference in
the height of two columns of fluid. The fact that
one column travels further than the other does
not affect the accuracy of the reading.

CLEANING

Cleaning can best be accomplished with a little
pure soap and water. Avoid liquid soaps and
solvents. Flush thoroughly with clear water to
remove all soap. Dry completely before refilling
with mercury.

Slack Tube®Manometer extended
with cross-sectional view of molded
unbreakable Acrylic plastic top,
connectors and over pressure traps.

OPERATING RANGES

Model
1211-8
1211-12
1211-16
1211-24
1211-30
1211-36
1211-48
1211-60
1211-72
1211-120
Metric
1211-50
1211-100
1211-200

Range, In.

4-0-4
6-0-6
8-0-8
12-0-12
15-0-15
18-0-18
24-0-24
30-0-30
36-0-36
60-0-60

Range,CM

25-0-25
50-0-50
100-0-100

Hg Req’d (oz.)

6
7
9
12-1/2
15
17-1/2
22-1/2
27
32
57

Hg Req'd (oz.)

11
18-1⁄2
35