Kobold DW Series User manual

KOBOLD DW SERIES FLOWMETER
User Instructions
DW_manual_3-04
KOBOLD Instruments Inc.
1801 Parkway View Drive
Pittsburgh, PA 15205
412-788-2830 Fax [phone]
KOBOLD Instruments Canada Inc.
9A Aviation
Point Claire, QC H9R 4Z2
514-428-8090 Fax [phone]
www.koboldusa.com

Table of Contents
1.0 General .................................................................................................. 1
2.0 Specifications ........................................................................................ 2
3.0 Installation Instructions........................................................................... 6
4.0 Operation .............................................................................................. 7
4.1 Adjusting the Setpoint ............................................................... 7
5.0 Maintenance .......................................................................................... 8
6.0 Arrival of Damaged Equipment .............................................................. 8
7.0 Need Help With Your DW ........................................................................ 8
List of Diagrams
Diagram 1.5 Function Diagram ......................................................... 1
Diagram 2.3 Electrical Connections ................................................. 3
Diagram 2.5 Wiring Diagram & Specifications for DWU w/ 4-20mA 4
Diagram 2.6 Dimensions ................................................................... 5
List of Tables
Table 2.1 Technical Data ................................................................ 2
Table 2.2 Material Combination & Operating Limits ........................ 3
Table 2.4 Microswitch Data ............................................................. 4
Table 3.1 Flow Symbol Key ........................................................... 6

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KOBOLD DW SERIES FLOWMETER
User Instructions
CAUTION: For safety reasons, please read the cautionary information located at
the end of the manual, before attempting installation.
1.0 General
The KOBOLD DW flowmeters and switches are intended for use in monitoring and
measuring (DWU only) control applications involving high flow rates and/or dirty media.
The DWS and DWP versions monitor flow rate through a setpoint feature. At setpoint, an
internal microswitch is activated, allowing control of other equipment. The DWU has the
same setpoint triggering capability as well as a meter scale for displaying flow rate.
The devices operates as follows:
1. Flowing medium impacts upon a paddle attached to a lever which has its pivot
point in the instrument housing (see diagram 1.5). This causes the paddle and
lever arrangement to pivot about its hinge point.
2. The motion of the paddle is opposed by a spring whose strength determines
the range of the instrument. The motion of the paddle is coupled to an
indicator dial, in the DWU, calibrated for the flow rate of the device.
3. Positioned in the path of the paddle/lever is a microswitch contact. When the
lever pivots through a preset angle, the microswitch is activated.
Diagram 1.5; Function Diagram

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Operation:
a. Flowing medium exerts force on paddle (1).
b. Motion of paddle is opposed by spring (2).
c. Bellows (3) isolates the paddle from the rest of the system. It also opposes
paddle motion due to its own spring constant.
d. Motion of paddle operates pointer (4) which indicates flow on scale (5).
e. If the paddle pivots further than a preset angle, a microswitch (6) is activated.
This causes a lamp (7) to change state.
f. Screw (on face of DWS, or rear of DWU) is used to position the microswitch at
the desired setpoint. DWP versions have a factory preset switchpoint and are
not field adjustable.
The mechanical/electronic portion of the DW is isolated from the medium through use of
a bellows. Since the bellows is elastic, a pressure difference between atmosphere (one
surface of the bellows) and the medium (the other side), will result in a change of the
bellows' spring constant. It is important, therefore, that the DW series be used only at
their intended operating pressure if accurate flow readings are desired.
2.0 Specifications
Table 2.1; Technical Data
Operating Principle: Paddle/bellows arrangement
Dimensions: See Diagram 2.6
Range: 4:1 or 5:1 (depending on pipe size)

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Table 2.2; Material Combination & Operating Limits
Diagram 2.3; Electrical Connections
Component
Material Combination
0200 0300
T-Piece Brass 316-Ti SS
Paddle Brass 303 SS
Bellows 316-Ti SS 316-Ti SS
Housing: Measuring Section Matte Aluminum
Housing: Cover Clear Polycarbonate
Flanges (on Flanged Units) Galvanized Steel 316 SS
Maximum Operating Pressure 145 PSIG
Maximum Operating Temperature 210° F
Maximum Ambient Temperature 160° F

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Table 2.4; Microswitch Data
Quantity: 1 or 2 SPDT
Switch Hysteresis: +/- 10%
Maximum Load: 10 A/250 V, 2500 VA maximum
Status Lamp Power Supply: 220 VAC, or 110 VAC, or 24 VDC
Diagram 2.5 Wiring Diagram for DWU Series with 4-Wire 4-20 mA Transmitter/
LCD Display
KL1
KL2
+ 24 VDC
- GND
+ 4-20 mA
- GND
SPDT Relays (optional) are connected at KL1
Power and Analog output are connected at KL2
Power: Connected at +24 VDC and GND
Output: 4-20 mA active, connected at
+ 4-20 mA and GND.
Specifications for DWU with LCD and Analog Output
Output: 4 - 20mA, 4-wire
Load: 0-500 Ohms
Power Requirement: 24 VDC +/- 10%
Display: 8- Digit LCD with option AN1
Adjustments: Zero: +/- 4%
Span:+/-10%
Optional Relays: 0, 1 or 2 SPDT
Maximum Load: 1A @ 230 VAC
Protection: NEMA 4

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Diagram 2.6; Dimensions

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3.0 Installation Instructions
CAUTION: For safety reasons, please read the cautionary information located at
the end of the manual, before attempting installation.
The KOBOLD DW series meters and switches are to be installed in the orientation
described by the symbol on the identification tag. (See Symbol Key, Diagram 3.1). In
general, the DW series may be installed in any desired position. The user, however,
must specify the installation orientation so that the flow scale is calibrated for this position
DURING MANUFACTURE. Installation in other positions will lead to inaccurate flow rate
indication.
Table 3.1; Flow Symbol Key
= To the left of line
= To the right of line
= Horizontal flow, left to right
= Horizontal flow, right to left
= Vertical flow, down
= Vertical flow, up
The DW is connected to your system in one of three fashions:
1. Pipe Fittings: Connect in direction indicated using appropriate tools.
2. Flange Connection: Connect in direction indicated using the flanges and the
gasket provided.
3. Weld Connection: The weld-on DW’s come with two flanges; one is
connected to the DW and the other to the joint to be welded to your pipe. Cut
a hole in the pipe into which the flange pipe will fit cleanly. This will guarantee
that travel of the paddle will not be hindered.
In welding the flange pipe to your system, it is important to keep the distance
between flange face and top of your system pipe at 50mm (See Diagram 2.6,
Dimensions). If this distance is not observed, flow rate measurement errors
will occur.
Observe also that when the flowmeter is re-installed on the flange, it
positioned so that the flow direction in the pipe and that indicated on the
instrument, match after installation.

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After welding, make sure that the interior of the weld joint is clean and no metal
protrudes. This will ensure that the paddle can move freely after mounting. A
tight flange to flange seal is obtained through the use of the supplied rubber
gasket.
To obtain accurate flow readings, it is necessary to establish reproducible flow
conditions in front of and behind the DW installation point. To do this, straight
lengths of pipe are needed on either side of the flow switch. The needed
lengths are:
Upstream: 10 x d
Downstream: 5 x d
(d = Inner Pipe Diameter)
4. If you wish to use the setpoint switch, then connect as follows: Remove the
plastic housing cover by first removing the two hold down nuts on the bottom
of the housing and then lifting the housing off the electrical assembly. Feed
your wiring through the watertight strain relief fixture at the bottom of the
electrical housing. Connect your wiring according to Diagram 2.3. Tighten the
strain relief nut around your cabling to insure a watertight seal. Replace the
plastic housing cover and refasten using the hold down nuts.
4.0 Operation
The DWU version indicates flow rate on its large circular scale through use of a pointer
indicator. The DWS has no indication, only an adjustable switchpoint.
Both devices have a single set point that is user adjustable within the range of the
instrument.
DWP versions have a factory preset switchpoint that is not field adjustable.
4.1 - Adjusting the Setpoint
Proceed as follows:
1. Remove the clear plastic cover from the instrument.
2. On the face of the DWS body (or the rear for DWU) is a screw with a pointer
and dial face graduated to the instrument's flow rate. Adjust this screw so that
the pointer indicates the flow amount desired for setpoint.
3. Replace the plastic cover.

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5.0 Maintenance
Due to its construction, a paddle type flowmeter, such as the DW series, is nearly
maintenance-free. There are only two areas that could (potentially) be a source of
concern if the medium contains minerals which could precipitate out onto the instrument.
1. If enough material deposits on the paddle, its area may be enlarged. This will
lead to high flow rate readings.
2. In extremely severe cases, it may be possible that sufficient materials will
deposit inside the bellows to alter the bellows' spring constant. This will lead
to low flow rate reading (stiffening of the bellows).
If you find it necessary to clean your instrument, do not use any sharp metal instruments
to scrape away deposits. Use only solvents not aggressive to the instrument to remove
deposits.
6.0 Arrival of Damaged Equipment
Your instrument was inspected prior to shipment and found to be defect-free. If damage
is visible on the unit, we advise that you carefully inspect the packing in which it was
delivered. If damage is visible, notify your local carrier at once, since the carrier is liable
for a replacement under these circumstances. If your claim is refused, please contact
KOBOLD Instruments for further advisement.
7.0 Need help with your DW Series?
Call one of our friendly engineers at 412-788-2830.

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Caution
PLEASE READ THE FOLLOWING GENERAL FLOW METER/ MONITOR
WARNINGS BEFORE ATTEMPTING INSTALLATION OF YOUR NEW
DEVICE. FAILURE TO HEED THE INFORMATION HEREIN MAY
RESULT IN EQUIPMENT FAILURE AND POSSIBLE SUBSEQUENT
PERSONAL INJURY.

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• Inspect instrument for damage upon arrival. Cracked, fractured, bent or otherwise
damaged instruments must not be put into use, since the device is weakened to an
unknown extent. (The operations and installation guide will explain how to make a
claim on damaged instruments.)
• Under NO circumstances must the maximum tolerances (temperature and pressure)
be exceeded.
• Diagrams 2.3, 2.5 and Table 2.4 provide the voltage and current limitations and the
wiring for the various sensor types. The sensor electrical ratings should never be
exceeded. Electrical wiring of the sensor should be performed in accordance with all
applicable national, state and local codes
• The maximum tolerances of the device have been determined using water, air and/or
oil. If using other media, especially corrosive ones, it is critically important that the
user determine chemical compatibility with our instruments. A list, detailing material
composition of our instruments, is available from KOBOLD Instruments Inc. upon
request. KOBOLD Instruments Inc. cannot accept responsibility for failure and
consequences resulting from use of media other than water, mineral oil, air, and
nitrogen.
• Install the device in a fully supported position within your flow system. This avoids
excessive stresses which may damage the instrument. In particular:
a. Ensure that the plumbing leading to and from the instrument is fully supported
and that the instrument does not perform the physical function of a joint.
b. When calculating stress on the device caused by plumbing, the weight of the
medium in the pipes must be considered as well.
c. Misaligned runs of rigid piping can cause large stresses when connected to
the instrument. Do not connect in such a fashion.
• During installation, avoid stresses on the instrument by following guidelines given
below:
a. When connecting fittings, hold the instrument fittings rigid with a correctly
sized wrench. Do not install by twisting the instrument into the pipe fittings.
b. Do NOT install by holding the device housing to provide counter-torque to the
pipe fitting.
c. Use an appropriate amount of teflon tape on male threads of fitting. This
reduces the twisting stresses produced by tightening the fittings into each
other.
d. Do not use pliers or wrenches on the housing, as this may damage it.
e. Do not overtighten, as this may fracture the fittings.

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• During operation, there are a number of situations to avoid:
a. The sudden cessation of fluid flow causes what is typically referred to as
"water hammer". Most people are familiar with this phenomenon from their
home experience - it is the cause behind the loud clank of water pipes which
occurs when faucets are turned off too suddenly. The cause behind this
"water hammer" is quite easy to visualize. Water is fairly massive. The
amount of water in long runs of pipe is quite substantial. When the faucets
are turned off suddenly, especially from a full on condition, the water has
considerable momentum and does not want to stop flowing. The situation is
similar to stopping a car by running into a wall, rather than by applying brakes.
Both are sudden rather than gradual. The damage to the wall can be
substantial (not to mention the car).
The "water hammer" causes surges in fluid pressure which could cause the
measurement instrument's pressure limit to be exceeded, resulting in failure
and possible personal injury.
b. Fluid surges, as well as the water hammer, can be particularly damaging to
empty flowmeters since there is no back pressure in the device. The damage
is caused, once again, by momentary excess pressure. To avoid these surges,
fluid lines should remain full (if possible) and water flow should be introduced
to the device slowly.
c. If the instrument is isolated with inlet and outlet valves, the flowmeter must be
completely drained when said valves are both closed. Failure to do so could
result in damage to the device caused by thermal expansion of fluid.
d. Freezing of water in the instrument must be avoided since the resultant
expansion will damage the flowmeter and make it unsafe for use.