Dwyer Instruments DS-300 Series Installation And Operating Instructions

Series DS-300 Flow Sensors are averaging pitot tubes
that provide accurate, convenient flow rate sensing. When
purchased with a Dwyer Capsuhelic
Magnehelic ® for air flow, differential pressure gage of
appropriate range, the result is a flow-indicating system
delivered off the shelf at an economical price. Series DS-300
Flow Sensors are designed to be inserted in the pipeline
through a compression fitting and are furnished with
instrument shut-off valves on both pressure connections.
Valves are fitted with 1/8˝ female NPT connections.
Accessories include adapters with 1/4˝ SAE 45° flared ends
compatible with hoses supplied with the Model A-471
Portable Capsuhelic ® kit. Standard valves are rated at 200°F
(93.3°C). Where valves are not required, they can be
omitted at reduced cost. Series DS-300 Flow Sensors are
available for pipe sizes from 1˝ to 10˝.

INSPECTION

Inspect sensor upon receipt of shipment to be certain it is
as ordered and not damaged. If damaged, contact carrier.

INSTALLATION

General - The sensing ports of the flow sensor must be
correctly positioned for measurement accuracy. The
Instrument Connections on the sensor indicate correct
Positioning. The side connection is for total or high pressure
and should be pointed upstream. The top connection is for
static or low pressure.
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A.
Series DS-300 Flow Sensors
Installation and Operating Instructions Flow Calculations
® for liquid flow or
QualityInstruments-Direct
1/4 MALE NPT
Location - The sensor should be installed in the flowing line
with as much straight run of pipe upstream as possible. A
rule of thumb is to allow 10 - 15 pipe diameters upstream
and 5 downstream. The table below lists recommended up
and down piping.

PRESSURE AND TEMPERATURE

Maximum: 200 psig (13.78 bar) at 200°F (93.3°C).
Upstream and Downstream Dimensions in
Terms of Internal Diameter of Pipe
Upstream Condition
In-Plane
One Elbow or Tee 7
Two 90° Bends in
8
Same Plane
Two 90° Bends in
18
Different Plane
Reducers or Expanders 8
All Valves**
24
* Values shown are recommended spacing, in terms of internal diameter for normal industrial
metering requirements. For laboratory or high accuracy work, add 25% to values.
** Includes gate, globe, plug and other throttling valves that are only partially opened. If valve is to
be fully open, use values for pipe size change. CONTROL VALVES SHOULD BE LOCATED
AFTER THE FLOW SENSOR.
Phone: 219/879-8000 www.dwyer-inst.com
Fax: 219/872-9057 e-mail: info@dwyer-inst.com
.ca
Bulletin F-50
1-15/16 (49.21)
1-5/8 (41.27) TYP
LP
1-3/4 (44.45)
HP
1-11/16 (42.86)
5/16 (7.94)
*
Minimum Diameter of Straight Pipe
Upstream
Downstream
Out of Plane
9 5
12 5
24 5
8 5
24 5
1.800.868.7495