Kobold ZDM-XX08 Series, ZDM-XX02 Series, ZDM-XX09 Series, ZDM-XX10 Series, ZDM-XX20 Series User Instructions

ZDM Positive Displacement Flow Meter

User Instructions

USA

1801 Parkway View Drive
Pittsburgh, PA 15205
PH 412-788-2830

www.koboldusa.com

Canada

9A Aviation
Point Claire, QC H9R 4Z2
PH 514-428-8090

ZDM_manual_11-10

Table of Contents

Topic Page

1.0 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.0 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2.1 Principle of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2.2 Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2.2.1 Mechanical Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Filtration Requirements. . . . . . . . . . . . . . . . . . . . . . . . 3

Electrical Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.2.3 Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.2.2 Pressure Loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.0 Installation Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1 Mechanical Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1.1 Installing the Mounting Plate. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1.2 Attaching the Flow Sensor to the Mounting Plate. . . . . . . . . . . . 4

3.1.3 Bolt Torque Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1.4 Connecting Piping to the Sensor . . . . . . . . . . . . . . . . . . . . . . . . 5

3.2 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4.0 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.1 Turning the Unit On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.2 Flow Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4.3 Turning the Unit Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5.0 Arrival of Damaged Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6.0 Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7.0 Need Help with your ZDM Sensor? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Appendix A: Pressure Loss vs. Flow Rate at Various Viscosities . . . . . . . . . . . 9

List of Diagrams

Diagram 3.2.1 ZDM Wiring Schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Diagram 4.2.1 ZDM Frequency Output Waveform. . . . . . . . . . . . . . . . . . . . . . . 6

List of Tables

Table 1: ZDM Wetted Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Table 2: Volume per Pulse for Various ZDM Ranges. . . . . . . . . . . . . . . . 7

ZDM

KOBOLD ZDM POSITIVE DISPLACEMENT FLOWMETER

User Instructions

CAUTION: For safety reasons, please read the cautionary information located at

the end of this manual, before attempting installation.

1.0 General
Congratulations on your purchase of a Kobold ZDM Positive Displacement flowmeter.

The ZDM is one of the most precise and reliable low volume, liquid flow measuring
products available today.

The ZDM operates on the viscosity and density independent volumetric principle. Two
gears are brought into counter-rotation by the force of liquid moving past the gears along
the meter’s housing. Engagement of the gear teeth with the housing walls entraps a
defined volume in the cavity between the gear teeth. A detector counts the gear teeth as
the cavities empty into the exit port. The precision of the meter is defined by the gear
cavity volume. The ZDM can meter volumes as low as 0.02 CC (cubic centimeters.) This
ultra-high precision is coupled with bi-directional flow capability, viscosity compatibility to
100,000 cS t and a mechanical robustness ca pable of pressures to 6500 PSIG (450 BAR).

The ZDM is the ideal choice for difficult clean liquid applications involving media with
lubricating properties ranging from very slight, to extensive.

FM Rev. 11/10

ZDM 2

2.0 Description

2.1 Principle of Operation

The ZDM operates on the volumetric displacement principle. The meter moves pocket s of
liquid from the inlet port to the exit port in discrete segments of known volume. These
pockets are defined by the space between adjacent gear teeth and the internal housing
wall.

As liquid enters the meter, the inlet cavity fills. The liquid pressure forces the meter’s
gears to rotate from the gear mesh-point inwards. The ge ar teeth ca vities fill with liqu id in
the inlet side of the meter and remain filled as the teeth come into near-contact with the
meter’s interior walls. The gear teeth then drag the liquid to the exit cavity at the opposite
side of the meter. This process causes the exit cavity to fill since the liquid is squeezed
out of the spaces between the teeth at the gear mesh point. The liquid then flows out the
exit port of the meter.

A proximity sensor in the housing senses the passage of individual gear teeth. Since the
passage of a tooth signals the passage of its trailing space (filled with liquid), the system
as a whole signals with an electrical pulse every time a displaced amount is emptied into
the exit port. The resolution of the ZDM is, therefore, determined by the volume between
the gear teeth.

This entire procedure is completely independent of the properties of the liquid, making the
system applicable to a wide variety of media (even liquids with dynamically changing
characteristics.) The only limitations to the system are mechanical ones. Since metal to
metal contact is involved, the liquid must have some lubricating properties in order to
prevent excessive wear of the gear teeth. If the gear teeth wear down, liquid will leak p ast
them excessively. This excess leakage will degrade the meter’s accuracy. The required
amount of media lubricity is very slight. For example, leaded gasoline (such as jet fuel)
will work, while unleaded gasoline will not.

Another limitation is caused by the relatively high pressure loss inherent to positive
displacement technology. The pressure loss through the ZDM becomes unacceptable if
the media viscosity exceeds 100,000 cSt.

2.2

Specifications

2.2.1 Mechanical Data
Table 1: ZDM Wetted Parts

Nominal Construction Material

Wetted

Component

Housing Cast Iron 316 Ti SS (DIN 1.4571)

Cast Iron

(ZDM-X1XX)

316 Stainless Steel

(ZDM-X3XX)

FM Rev. 11/10

Gears SS* (DIN 1.4122) 316 Ti SS (DIN 1.4571)
Seals
Bearings Carbon Steel Tungsten Carbide
* Alloy content of DIN 1.4122 SS: X 35 Cr Mo 17. No direct AISI equivalent. Similar

to 400 series SS.

FKM (EPDM Optional) FKM (EPDM Optional)

3ZDM

Filtration Requirements

ZDM-XX02, -XX04, -XX07: 10 µM (1600 mesh)
ZDM-XX08, -XX09: 20 µM (750 mesh)
ZDM-XX10, -XX20, -XX40: 50 µM (250 mesh)

Maximum Pressure Rating: Cast Iron: 4500 PSIG

St. Steel: 6500 PSIG

Maximum Temperature Rating

Standard: -40 to 248°F

Accuracy: ±0.3% of reading with

viscosity >20 cSt.

Repeatability: ±0.05% of reading

Electrical Data

Sensor Type: Qty. 2 Push-Pull Outputs (Channels A & B)

A & B Signals are 90° out of phase.
Phase difference can be used to determine
flow direction using suitable receiving equipment.

Power Requirements

Voltage (V

): 10-28 VDC

cc

Current: 80 mA max. @ 24 VDC
Power: 1.92 W max. @ 24 VDC

Output Signal

Type: DC voltage pulse
Form: Square wave
Amplitude: Low = GND, High = V

- 1.0 VDC

cc

FM Rev. 11/10