Kobold Kal-K Specifications

Thermal Flow Switch

for Water-Based Liquids

measuring

•

monitoring

•

analyzing

KAL-K

• Flow Velocities from 0.04...2 m/s

• T

: 250 °F, P

max

: 1450 PSIG

max

• NPT and 3-A Compliant Sanitary Fittings

• No Moving Parts

• Intelligent Temperature Compensation

• Extremely Low Pressure Loss

• Easy to Operate

• Insensitive to Dirt

KOBOLD companies worldwide:

ARGENTINA, AUSTRALIA, AUSTRIA, BELGIUM, BULGARIA, CANADA, CHILE, CHINA, COLOMBIA,
CZECH REPUBLIC, EGYPT, FRANCE, GERMANY, HUNGARY, INDIA, INDONESIA, ITALY, MALAYSIA,
MEXICO, NETHERLANDS, PERU, POLAND, REPUBLIC OF KOREA, ROMANIA, SINGAPORE, SPAIN,
SWITZERLAND, TAIWAN, THAILAND, TUNISIA, TURKEY, UNITED KINGDOM, USA, VIETNAM

05/07-15-2019

KOBOLD Instruments, Inc.
1801 Parkway View Drive
Pittsburgh, PA 15205

Main Ofce:

1.800.998.1020

1.412.788.4890
[e-mail]
www.koboldusa.com

Temperatur (C)

0

80

2

Thermal Flow Switch Model KAL-K

Description

The KAL-K thermal flow switch utilizes KOBOLD’s temperature
compensating electronics. This compact, one-piece unit
provides reliable readings unaffected by temperature or physical
characteristics of non-viscous water-based liquids. This is made
possible through the use of state-of-the-art microprocessor
technology. The microprocessor can be field calibrated to both
the liquid properties and operating range in a simple, five minute
set-up procedure. This intelligence, coupled with a “no moving
parts” design, make the KAL a superior performer in virtually all
applications. The KAL-K is also offered in a 3-A compliant version.

The KAL-K incorporates an 8 segment bar-graph LED flow
trend indicator and one flow alarm setpoint. The setpoint is fully
configurable as NPN, PNP, normally open or normally closed.

Operation

The KAL design is based on the time proven calorimetric
principle. The sensor is internally heated to a few degrees above
the temperature of the media. Flow causes removal of heat from
the sensor, resulting in a cooling effect. The rate of cooling is a
measure of the flow velocity. The microprocessor based design
of the KAL distinguishes it from the competition. Full temperature
compensation of the flow rate is readily obtained through a simple,
one-time, calibration procedure. This assures elimination of flow
rate reading drift caused by temperature variations in the process
liquid.

KAL Timing - Heating and Measuring Cycle

Temperature Compensation

The KOBOLD KAL flow products use a microprocessor to
compensate for temperature changes through use of an internal
look-up table. End-users can easily adapt the equipment to the
requirements of their unique installations. Unlike conventional
calorimetric flow switches, the technically advanced design of the
KAL provides a flow reading which is unaffected by temperature.

Operating Behavior

1. At t=0, the probe temperature is recorded. This reading
represents the ambient liquid temperature.

Schaltpunktveränderung über Temperatur

2. Still at t=0, the KAL begins heating the probe.

3. At t=0.8 seconds, the heating cycle ends and the KAL begins
monitoring the probe temperature.

KAL-... with compensation

KAL-... mit Kompensation

4. At t=1.8 seconds, a temperature reading is taken and
compared to the t=0.8 second temperature. The rate of cooling

Schaltpunkt (m/s)

Switch point (m/s)

Standard without

Herkömmlich

compensation

ohne Kompensation

is calculated and compared to a Cooling Rate vs Flow Rate
table specific to the ambient temperature recorded at t=0.

5. The probe is allowed to cool until t=5.6 seconds. A
temperature reading is taken and compared to the initial t=0
reading. If the temperatures are equal (or nearly so), the flow
reading is determined valid and passes through to the KAL
output. If the temperatures are not equal, the KAL waits

20 30

40

Temperature °C

50

60

70

another 5.6 sec, and Step 5 repeats.

2

www.koboldusa.com

No responsibility taken for errors;

subject to change without prior notice.