Series 1221/1222/1223 Flex-Tube® U-Tube Manometer
Suitable for Pressures up to 100 psi, Better Precision
These inexpensive manometers measure positive, negative and differential pressures. Dwyer® Flex-Tube® U-Tube Manometers combine the inherent accuracy of the simple "U" Tube with the durability of tough, long-lasting plastic construction. Columns are of .375" O.D. flexible and shatter proof clear butyrate tubing. They are easily accessible for cleaning. Indicating tube is backed by white scale channel to provide maximum color contrast. Scales are extruded high impact polystyrene plastic, formed to hold columns in perfect alignment. Stark white scales have graduations and numbers silkscreen-printed in black for maximum legibility.
You can choose from numerous models and features including over-pressure safety traps, in full scale ranges from 8" to 36" of water or mercury. All are suitable for total pressures to 100 psi - for determining velocity and static pressures, leakage, fan and blower efficiency, filter resistance, and gas pressures. Ideal wherever a portable, direct reading manometer is needed. Standard ranges and markings as shown, or special ranges, colors, logos and brand names for OEM quantity orders are available.
- Duct static pressure
- Calibration labs
- Filter monitoring
Models & Ordering
- Minor Divisions of 1/10" water column (or 2mm water column on metric units) are silkscreened in jet black on stark white scale for positive definition. Easy to read, even at a distance, they are acrylic coated for permanence. All models are furnished with one 3/4 ounce bottle of fluorescein green color concentrate with special wetting agent for W/M models, or 3/4 ounce bottle of red gage fluid for "D" units.
- Series 1221 Manometer - Our simplest, lowest cost basic U-gage. A dependable U-tube manometer that withstands hard use and provides accurate, high visibility readings. For use with water, mercury or red gage fluid. For mercury filled manometers, a scale clamp bar, Dwyer® Part No. A-363 (available as an extra for Series 1221 - and standard on Series 1222) is recommended. One pair of carrying plugs and a pair of non-kink vinyl tube connectors are included with each manometer.
- Series 1222 Manometer - All the features of the 1221 plus magnetic clips for mounting to any vertical steel surface, and clamp bar to insure against U-tube slipping. (Especially recommended for manometers used with mercury.) Both magnets are easily removed and replaced at the user's convenience.
- Series 1223 Manometer - Our finest U-gage - for either portable or stationary use. Safety traps prevent loss of indicating fluid in case of accidental over-pressure. Tubing is permanently bonded to a molded, high impact acrylic plastic top that contains safety traps. Large magnetic clips and clamp bar are provided. Standard type "a" connections include two rapid shut-off type molded nylon tubing connections, two 3' lengths of flexible Tygon® plastic tubing, and two 1/8" pipe thread to tube adapters.
|Model Number||Description||Usually Ships*||Price||Order|
|A-101||1 oz dispenser bottle of red gage fluid, .826 sp. gr.||Next Day||$7.50||Order|
|A-102||4 oz bottle of red gage fluid, .826 sp. gr.||Next Day||$14.50||Order|
|A-103||1 pt bottle of red gage fluid, .826 sp. gr.||Next Day||$33.00||Order|
|A-104||1 qt bottle of red gage fluid, .826 sp. gr.||Next Day||$62.00||Order|
|A-126||1 oz dispenser bottle fluorescein green color concentrate.||Next Day||$11.00||Order|
|A-220||Clear flexible vinyl tubing is easily inspected, and is therefore best for test applications where a possibility of fluid entering the tubing exists. 3/16" ID x 5/16" OD, lengths to 500'; 45 psi maximum pressure @ 73°F.||Next Day||$0.25||Order|
|A-339||Adapter, brass, 1/8" NPT to 3/16" rubber and 1/8" ID plastic tubing.||Next Day||$4.00||Order|
|A-364||Magnet assembly for 1222 manometers, 2 required (3 required for 1222-36 and M-1000).||Next Day||$7.30||Order|
|A-319||Flexible red PVC connector, 3/16" ID rubber tubing to 1/4" ID plastic tube for 1221,1222 and 1227 manometers.||Next Day||$3.50||Order|
|A-363||Scale clamp bar for 1221 manometer.||1-2 Weeks||$5.20||Order|
|EXAMPLE||1221||8||W/M||AT||Series 1221-8-W/M-AT U-Tube Manometer, range 4-0-4" w.c. using water/mercury, with aluminum tag.|
100-0-100 mm w.c.
150-0-150 mm w.c.
200-0-200 mm w.c.
300-0-300 mm w.c.
500-0-500 mm w.c.
Inches of Water/Mercury
Inches of Water Using Red Gage Fluid
NIST Certificate of Calibration
Type B Connections (available with 1223 only)
Type C Connections (available with 1223 only)
Type D Connections (available with 1223 only)
Type E Connections (available with 1223 only)
- What are the principle advantages of red gage fluid over water for use in manometers?
- Red gage fluid is slow to evaporate, won't freeze, is more readable and produces slightly expanded scales for better reading resolution.
- Is routine maintenance required for a Dwyer red gage fluid type manometer?
- Yes. The zero point should be checked periodically as well as the fluid level. After a year of service, particularly with dirty air, the fluid should be replaced to assure that specific gravity changes are not affecting the accuracy of the reading.
- Will the water manometers freeze?
- Yes, if the temperature drops below 32 degrees Fahrenheit, the fluid in the manometer will freeze. The fluid used in "W/M" style manometers is water-based with a small amount of fluorescent green fluid to enhance the meniscus. The other gage fluids have a lower freezing point, however, it is recommended that the manometers be stored above 32 degrees Fahrenheit.
- Since water will not mix with oil, why can't a D-style manometer be used to measure water pressures?
- The weight of the water itself is also being measured which results in erroneous readings.
- Why doesn't 1 inch on the scale of a 1223-12-D manometer equal 1 inch on a ruler?
- The calibration scale on the manometer has been compensated for the specific gravity of red gage fluid which is less than water.
- Model 1212. How much fluid mixture is required? What is the best method to fill this unit?
- A 1 oz bottle of A-126 Fluorescein green color concentrate is added to a quart of distilled water. Remove a tubing connector from the manometer and pour the mixture in to mid-point level. Shake the manometer to remove air bubbles and slide the scale so the zero mark is in line with the meniscus of the two fluid columns.
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