Bulletin F-43
DWYER INSTRUMENTS, INC.
Phone: 219/879-8000
www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, IN 46361, U.S.A.
Fax: 219/872-9057
e-mail: [email protected]
Specifications - Installation and Operating Instructions
Series RM Rate-Master
®
Flowmeters
F
A
B
C
J
BACK WIDTH
K
D
E
G
H
I
FULL OPEN
L
The Series RM Rate-Master
®
Flowmeters
are furnished in three mod-
els (see Fig. 2), each available in a broad array of flow ranges with direct
reading scales for air, gas or water. Installation, operation and mainte-
nance are very simple. Only a few common-sense precautions must be
observed to assure long, trouble-free service.
CAUTION:
Rate-Master
®
Flowmeters are designed to provide satisfacto-
ry long-term service when used with air, water or other compatible media.
Refer to factory for information on questionable gases or liquids. Avoid
solutions of acids, bases or salts having a pH below 5.0 or above 8.5.
Caustic solutions, antifreeze (ethylene glycol) and aromatic solvents should
definitely not be used.
Calibration
Each Rate-Master
®
Flowmeter is calibrated at the factory. If at any time
during the meter’s life, you wish to re-check its calibration, do so only with
devices of certified accuracy. DO NOT attempt to check a Rate-Master
®
Flowmeter with a similar flowmeter, as seemingly unimportant variations in
piping and back pressure may cause noticeable differences in the indicat-
ed reading. If in doubt, return your Rate-Master
®
Flowmeter to the facto-
ry. Its calibration will be checked for you at no charge. Before proceed-
ing with installation, check to be sure you have the Rate-Master
®
flowme-
ter model and flow range you require.
LOCATION: Temperature, Pressure, Atmosphere and Vibration:
Rate-Master
®
Flowmeters are exceptionally tough and strong. They are
designed for use at pressures up to 100 psi (6.89 bar) and temperatures
up to 130°F (54°C).
DO NOT EXCEED THESE LIMITS! The installation should not be exposed
to strong chlorine atmospheres or solvents such as benzene, acetone,
carbon tetrachloride, etc. The mounting panel should be free of excessive
vibration, as it may prevent the unit from operating properly.
A
B
C
D
E
F
G
H
I
(OPEN)
J
K
L
4 -9/16 (11.59)
3 (7.62)
1/8 NPT CONN.
1-5/8 (3.17)
10 - 32 Thds.
3/8 (.95)
1-1/16 (2.60)
1-3/16 (2.73)
3/4 (1.91)
1 (2.54)
1-3/8 (3.49)
3/4 (1.91)
4-13/16 (12.22)
1 (2.54)
8-1/2 (21.59)
6-7/16 (16.35)
1/4 NPT CONN.
3-15/16 (8.56)
1/4 - 20 Thds.
5/8 (1.59)
1-7/8 (3.42)
1-3/4 (3.29)
1 (2.54)
1-7/16 (2.98)
1-13/16 (4.60)
1-1/4 (3.18)
8-3/4 (22.23)
1-1/2 (3.81)
Dimensions in Inches
(Centimeters)
15 -1/8 (38.42)
12 -1/4 (31.12)
1/2 NPT CONN.
8-3/4 (10.72)
10 - 32 Thds.
1 (2.54)
2-3/4 (5.83)
2-1/4 (5.33)
1-7/16 (2.98)
1-31/32 (3.51)
2-1/2 (6.35)
2 (5.08)
15-3/8 (39.05)
2-1/4 (5.72)
Inlet Piping Run:
It is good practice to approach the flowmeter inlet with
as few elbows and restrictions as possible. In every case, the inlet piping
should be at least as large as the connection to the flowmeter; i.e.,1/8
″
Iron Pipe Size for RMA models 1/4
″
IPS for RMB models,1/2
″
IPS for RMC
models. Length of inlet piping makes little difference for normal pressure-
fed flowmeters.
For flowmeters on vacuum air service, the inlet piping should be as short
and open as possible. This will allow operation near atmospheric pressure
and thereby insure the accuracy of the device. (
Note:
for vacuum air ser-
vice, the flow control valve, if any, should be on the discharge side of the
flowmeter. Either the TMV unit or a separate in-line valve may be applied.).
Discharge Piping:
As on the inlet, discharge piping should be at least as
large as the flowmeter connection. Also, for pressure-fed flowmeters on
air or gas service, the discharge piping should be as short and open as
possible. This will allow operation of the flow tube at near atmospheric
pressure and insure the accuracy of the device. This is of less importance
on water or liquid flowmeters, as the flowing medium is generally incom-
pressible and moderate back pressure will not affect the accuracy of the
instrument as calibrated.
POSITIONING AND MOUNTING
All Rate-Master
®
Flowmeters must be mounted in a vertical position with
inlet connection at the bottom rear and outlet at the top rear.
Bezel or Through-Panel Mounting:
Make panel cutout using appropri-
ate dimensions from Fig. 2. Flowmeter must fit into panel freely without
forcing or squeezing. Insert the flowmeter from the front of the panel and
install the mounting clamps from the rear. Insert and tighten the clamp
bolts in the locations shown in Fig. 3. Do not exceed 5 in./lbs. Make con-
nections to inlet and outlet ports using pipe thread sealant tape to avoid
leakage. Avoid excess torque, which may damage the flowmeter body.
PANEL CUTOUT FOR FLUSH MOUNTING
4-5/8 (11.75)
7/8 (2.22)
7/16 (1.11)
1/4 (0.64)
8-9/16 (21.75)
1-5/16 (3.33)
5/8 (1.59)
9/32 (0.71)
15 -3/16 (38.58)
2-1/16 (5.24)
15/16 (2.38)
13/32 (1.03)
HIGH
WIDE
PIPE
BOLT
Model RMA Model RMB Model RMC
Fig. 1
Fig. 2
PANEL HOLE SIZES FOR SURFACE MOUNTING
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