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

DW
FM Rev 03/04
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

DW 2
FM Rev 03/04
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)

3DW
FM Rev 03/04
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

DW 4
FM Rev 03/04
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

5DW
FM Rev 03/04
Diagram 2.6; Dimensions

DW 6
FM Rev 03/04
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.