Dwyer Instruments SSM Series, SSB Series Installation And Operating Instructions Manual

Bulletin F-41-B

10.780
[273]

2.810
[71.4]

2.680
[68]

4.026
[102]

3/4" NPT

Ø 1.350 [34.3]

Ø 2.754

[70]

MODEL SSM110,111,112

MODEL SSM113,115

15.640
[397]

4.503
[114]

3.710
[94]

5.695
[145]

Ø 2.480

[63]

Ø 4.010

[101.8]

1-1/2" NPT

124072

Series SSM & SSB All Metal Flowmeters

Specifications - Installation and Operating Instructions

Series SSM 316 & SSB All Metal Flowmeters are ideal for dirty or

opaque fluids, high temperature and high pressure service and harsh
environments. The direct reading scale provides ±2% accuracy.
Flowmeters can quickly be disassembled without removing the body from
the pipeline for easy cleaning.

SPECIFICATIONS
Service: Compatible liquids.
Wetted Material: T316 SS, Alnico magnet, FKM O-ring.
Temperature Limits: 300ºF (149ºC), temperatures from 300˚F to 600°F

(149˚C to 316°C) require “hot top” sold separately.

Pressure Limits: 3/4” models: 1000 psig (68.9 bar) @ 250ºF (121ºC),

SAFETY PRECAUTIONS

Personnel safety should be considered before pressurizing and operating
the system. There are numerous possibilities for error in system operation
and maintenance as well as component installation. Because human eyes
must necessarily come into close proximity with the flowmeter to read it,
Dwyer Instruments, Inc. recommends that safety shielding such as a sheet
of transparent, high impact material be used in front of the meter. If

1-1/2”models: 800 psig (55 bar) @250ºF (121ºC).
(See the chart on pg. 6 for temperature vs.. pressure ratings.)

Accuracy: ±2% full scale.
Repeatability: ±0.5% of indicated flow rate.
Process Connections: 3/4” or 1-1/2” female NPT.
Scale Length: 3/4” models: 3.2” (8 cm); 1-1/2” models: 5.2” (13 cm).
Weight: 3/4” models: 5 lb (2.3 kg); 1-1/2” models: 13 lb (5.9 kg).

hazardous, toxic, or flammable fluids are being metered, recommended
safeguard should include methods to protect personnel from splash or
rebound. A method of quick, safe removal of dangerous fluids should also
be included.

INSTALLATION

PREPARATION: Series SSM & SSB All Metal Flowmeters are ready to
install as-is, although the sight tube may need repositioning so the scale is
visible after installation. First, remove the protective caps from the
connection ports. ALSO, REMOVE THE PLASTIC TUBING ABOVE THE
INLET CAP IN THE METER CORE TUBE! This tubing blocks the float
assembly in place during shipment. Check that the float moves freely within
the core tube, and that no packing materials are in the meter.

RECOMMENDED PIPING

Series SSM & SSB All Metal Flowmeters generally have no special straight
run or other piping requirements. Inlet piping should be the same size as
the meter connection. Some effect on meter accuracy may occur at high
flow velocities if inlet piping guidelines are violated. Please refer to the table
on the next page. When installing on different size pipe, use standard pipe
adapters and come into the meter inlet with a nipple 8 diameters long of
the same size for greatest accuracy. Control valves should be mounted on
the outlet side of the meter. The use of a three valve manifold around the
meter is suggested, as it allows uninterrupted process flow while the meter
is being cleaned.

PLUMBING-IN

While the flowmeters should be vertical, exact plumbness is not necessary .
A general rule is that if the meter appears plumb, it is close enough (even
if off by 10º, the predictable reading error is usually less than 1%). Pipe
should be cut to proper lengths to avoid stress on the meter. Avoid over­tightening, and do no use wrenches on the body or sight tube. If using

DWYER INSTRUMENTS, INC.

solvents in the vicinity of polysulfone sight tubes, the tube should be
removed until fumes clear.

SURGE & WATER HAMMER PREVENTION

Operating Limits are for non-shock conditions only. Flowmeters are more
accurate and less likely to be damaged when the fluid flow is smooth.
Water hammer is a hazardous phenomenon and should be eliminated from
any fluid system. Water hammer is a series of pressure shocks create by a
sudden change in the flow velocity of liquid in a pipe. This sudden change,
often caused by a fast acting valve or starting, stopping, or change in
speed of a pump, generates an immediate rise in pressure that sometimes
makes a noise similar to striking the pipe with a hammer. The pressure
wave is transmitted from the source throughout the system, subjecting
every component to the sudden shock. Pressure returns to normal only
when a larger vessel or pipe section is reached, the energy dissipated thru
friction and pipe expansion, or some component ruptures. Rupture of
piping, valves, flowmeters, or other components have obvious safety
ramifications that must be addressed.

Surge Chambers & Accumulators: Flowmeters are more accurate and less
likely to be damaged when the fluid flow is smooth. If the meter must be
installed on a line where reciprocating pumps causing pulsation are used,
surge chambers, accumulators, or desurgers are strongly suggested to
dampen the shock wave. This is a good, general practice for all
flowmeters.

SIGHT TUBE ROTATION: Series SSM & SSB All Metal Flowmeters use
magnetically-linked ball indicators and the scale usually may be positioned
over approximately a 300˚ range. However, the magnet position must also
be changed accordingly, requiring removal of the sight tube (see
“Disassembly”). On standard SSM & SSB All Metal Flowmeters as

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

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: [phone] e-mail: [e-mail]

depicted in Figure 1, the magnet slides out of the carrier at the top of the
float assembly. The screw holding the carrier to the float may be loosened
to allow rotation of the carrier toward the desired scale location. Re-tighten
the screw (thread sealant is recommended), replace magnet, and
reassemble the meter (see “Assembly”). Verify that the ball indicator has
been “captured” by the magnet. If not, rotate the sight tube (DO NOT twist
on the edges of the plastic raceway assembly) until the ball is “grabbed” by
the float magnet.

A

MAGNET

STARTUP: System flow should be started with the bypass valve open and
meter inlet and outlet valves closed. After the system is operating, open the
meter inlet valve gradually to equalize internal pressure. Then slowly crack
meter outlet valve and wait for float to stabilize. Finally, slowly open the
meter outlet and/or flow regulating valve all the way and close the system
by-pass valve. AVOID SUDDEN SURGES THAT CAUSE THE METER
FLOAT TO SLAM INTO THE TOP OF THE SIGHT TUBE! Although not
essential, the meter sight tube should be filled to a level above the float on
liquid systems. The snorkel tube (present in most standard models) allows
escape of entrapped gases except for a small pocket in the upper end
which helps cushion hydraulic shock. To assure proper filling and to flush
any foreign particles from the meter, operate the system at full flow briefly
at startup.

READING FLOW

Read flow directly from the scale as the number nearest to the center of
the ball indicator.

COMPENSATING FOR SYSTEM CHANGES

To find the correct flow reading for a system whose fluid conditions vary
from those for which the meter is scaled, use the conversion equations
provided. The most practical method of applying the formulae is to
calculate a conversion factor for the new system condition and multiplying
the scale reading by that factor . In the pr oblems to the right, “Q’s” has been
assigned a value of “1” to determine the conversion factor. (Dwyer
Instruments, Inc. can provide special scales at additional cost for other
fluids and/or units.)

A

BALL
INDICATOR

SNORKEL­GUIDE

FIGURE 1

METAL
PRESSURE
TUBE

POLYCARBONATE
COVER

SEC A-A, TOP VIEW

PHENOLIC
RACEWAY

CAUTION: DO NOT OPERATE THE FLOWMETER ON A SYSTEM

EXCEEDING THE OPERATING LIMITS OF THE UNIT. WHEN

CHANGING OPERATING CONDITIONS, MAKE SURE THAT THE

NEW SYSTEM CONDITIONS ARE WITHIN THE FLOWMETER

OPERATING LIMITS, AND ALL WETTED MATERIALS ARE

CORRECTING READINGS FOR NEW LIQUID CONDITIONS

Qa= Q

s

Where:
Qa=Actual flow, GPM (or same units as scale)
Qs=Meter reading from scale, (scale units)
ps=Specific gravity of calibration liquid related to water in std.
atmosphere at 70˚F being 1.00
pa=Specific gravity of metered liquid, same base
ds=Density of calibration liquid, lbs/ft3
da=Density of metered liquid, lbs/ft3
pf=Specific gravity of meter float
df=Density of the meter float as per Table below

Material

Stainless Steel
Brass

EXAMPLE: Using a standard brass meter scaled for water (ps = 1.00),
what is the conversion factor for an oil with a specific gravity of 0.85?

Thus, actual flow of the oil would be the observed scale reading times

1.096.

COMPATIBLE WITH THE FLUID.

Ps(Pf-Pa)

√

Pa(Pf-Ps)

FLOAT SPECIFIC GRAVITIES/DENSITIES

or Qa= Q

s

√

ds(df-da)
da(df-ds)

pf

8.05

8.30

Qa= 1.00 x

1.00 (8.30-0.85)

√

0.85 (8.30-1.00)

=1.096

df

501.1

516.6

FOR UNDERSIZED PIPES CONNECTED DIRECTLY TO FLOWMETER INLETS

PIPE

NPS

1/4
3/8
1/2
3/4

1
1-1/4
1-1/2

2
2-1/2

3

Data per

*
†

Cameron Hydraulic Data.

meter connections.
SCFM=0.445 x (psig + 14.7) x (ID)2. Based on 20 FPS max. air velocity having no effect on flowmeters accuracy if the inlet pipe is smaller than the
meter connections.

DATA

(ID)

0.132

0.243

0.387

0.679

1.100

1.904

2.592

4.272

6.096

9.413

MAXIMUM FLOWS (WITHOUT EFFECTING ACCURACY)

2

Based on 5 FPS max. liquid velocity having no effect on flowmeters accuracy if the inlet pipe is smaller than the

MAX. *

GPM LIQ.

1.72

2.98

4.74

8.31

13.47

23.32

31.74

52.29

74.56

115.2

ATMOS.

0.864

1.59

2.53

4.44

7.20

12.5

17.0

28.0

39.9

61.6

MAX. SCFM AIR @ †

50 PSIG

3.80

7.00

11.1

19.5

31.7

58.8

74.6
123
176
271

100 PSIG

6.74

12.4

19.8

34.7

56.1

97.2
132
218
311
480

200 PSIG

12.6

23.2

37.2

64.9
105
182
248
408
582
804

CORRECTING READINGS FOR NEW GAS CONDITIONS

s

√

Pg x Tsx P
Psx Tgx P

s
g

Qg= Q

Where:
Qg=SCFM, corrected to new conditions

Qs=SCFM read on meter scale
Pg=Operating pressure, psia (psig + 14.7)
Qs=Pressure stated on scale, psia (psig + 14.7)
Tg=Operating temperature, absolute (˚F +460)
Ts=Temperature stated on scale, absolute (˚F + 460)
Pg=Specific gravity of metered gas
Ps=Specific gravity stated on scale

EXAMPLE: If using a standard meter scaled for SCFM Dry Air @ 100 psig,
70˚F on argon (SP. GR.=1.378) at 50 psig, 100˚., what would the
conversion factor be?

MAINTENANCE
Upon final installation of the Series SSM & SSB All Metal Flowmeters, no
routine maintenance is required. A periodic check of the system calibration
is recommended. The Series SSM & SSB All Metal Flowmeters are not field
serviceable and should be returned if repair is needed (field repair should
not be attempted and may void warranty). Be sure to include a brief
description of the problem plus any relevant application notes. Contact
customer service to receive a return goods authorization number before
shipping.

Qa= 1.00

Thus, actual flow of the argon would be the observed scale reading times

0.622.

Series SSM & SSB gas flowmeters may be used for vapors such as steam.
The conversion factor may be determined with the following formula:

Where:
Mfh=Actual flow, lbs/hr.

Qm=Meter scale reading, Std. (SCFM Dry Air @ 100 psig, 70˚F)
Sv=Specific volume of media (from steam table)

EXAMPLE: When using a standard gas meter scaled from SCFM Dry Air @
100 psig, 70˚F, what is the conversion factor for lbs/hr. steam at 50 psig,
300˚F?

Thus, actual flow of steam in lbs/hr. would be the observed scale reading
times 2.267.

VISCOSITY CONSIDERATIONS

Each liquid flowmeter has so-called “Viscosity Immunity Ceiling” (V.I.C.).
Usually, if the viscosity of the metered liquid is less than the V.I.C., the
meter will be influenced significantly, and must be calibrated for that
viscosity. Effects of viscosity on a given flowmeter are not always
predictable. Two apparently similar liquids with comparable densities and
viscosities may impact meter calibrations quite differently. The table below
provides general guidelines for the typical maximum viscosity for meter
models without affecting accuracy.

64.7 x1.00 x530

√

114.7 x1.378 x560

STEAM

M

= Qm _______

fh

5.879

Mfh=

√6.727

5.879
√S

= 0.622

v

AVERAGE V.I.C., CENTISTOKES, FOR STANDARD

100% GPM,

3/4” METERS

0.54-0.80

1.20-2.60

3.80-7.00

10.0-23.0

“THRU VIEW” FLOWMETERS

CTS

0.54-0.80

1.20-2.60

3.80-7.00

10.0-23.0

100% GPM,

1-1/2” METERS

0.54-0.80

1.20-2.60

3.80-7.00

10.0-23.0

CTS

0.54-0.80

1.20-2.60

3.80-7.00

10.0-23.0