Kobold VKA-*102 series User manual

KOBOLD VKA FLOWMETER/SWITCH
User Instructions
Manual-VKA_03-04

VKA
FM Revision 3/24/04
Table of Contents
1.0 General . . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 1
2.0 Specifications. . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 2
3.0 Principle of Operation . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 5
4.0 Installation Instructions. . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 5
4.1 Mounting . . . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 5
4.2 Adjusting the Set point for Increasing Flow. . . . . . . . . . . . . . . . . . . . 6
4.3 Adjusting the Set point for Decreasing Flow . . . . . . . . . . . . . . . . . . 6
4.4 Contact Protection. . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 7
5.0 Arrival of Damaged Equipment . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 7
6.0 Need help with your VKA?.. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 7
List Of Diagrams
Diagram 2.3 Dimensions. . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 3
Diagram 2.4 Wiring of the Reed Switch. . . . . . .. . . . . . . . . . . . . . . . . . . . . 4
Diagram 2.6 Contact Protection. .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 7
List of Tables
Table 2.1 Material Composition. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 2
Table 2.2 Operational Limits. .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 2
Table 2.5 Electrical Data and Operational Limits. . . . . . . . . . . . . . . . . . 4

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KOBOLD VKA 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 VKA is a viscosity compensated flowmeter intended for use in applications
where changing viscosities of the measured media make flow determination difficult.
The VKA offers viscosity independent behavior for fluids in the range of 30-300 cSt (full
compensation). Ordinary float-type flow meters experience measurement errors of up to
1000% with this type of a viscosity change in the medium.
At a glance, the special features of the VKA are:
• Viscosity compensated for ∆v = 300 cSt (mm²/s) enabling use of same scale - no
need for recalibration.
• Density compensated for ∆p= 0.5 kg/l, enabling use of same scale - no recalibration
needed.
• Can be installed in any position.
• Can accurately measure flow of a wide range of media without recalibration.
• Compact.
• Up to 4 contacts availabe upon special request.
• Hermetic separation between media and indicator/ electronics.
• Suitable for dark and turgid liquids.
• Easy installation.
• Low Cost & Reliable.

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2.0 __ Specifications
Table 2.1; Material Composition
Table 2.2; Operational Limits
Viscosity Range: v= 30-300 cSt (mm²/s)
Maximum Medium Temperature: 212° F
Maximum Internal Pressure: 3600 PSIG
Material: Brass
Housi ng
Spring
Orifice
Magnet
Connections
Float
Seal
Nickel-plated Brass
301 Stainless Steel
301 Stainless Steel
Ceramic Oxide
Nickel-plated Brass
Brass
PTFE

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Diagram 2.3; Dimensions
* Larger fitting size listed in parenthesis is optional.
HEX (in) NPT L (in) B (in) D (in) E (in) Weight (lb.)
VKA-.102
VKA-.104
VKA-.106
VKA-.108
VKA-.110
VKA-.112
VKA-.114
VKA-.116
1.42
1.42
1.42
1.42
1.42
1.42
1.42
1.42
1/2 (3/4)*
1/2 (3/4)*
1/2 (3/4)*
1/2 (3/4)*
1/2 (3/4)*
1/2 (3/4)*
1/2 (3/4)*
1/2 (3/4)*
5.5
5.5
5.5
5.5
5.5
5.5
5.5
5.5
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
1.57
1.57
1.57
1.57
1.57
1.57
1.57
1.57
0.87
0.87
0.87
0.87
0.87
0.87
0.87
0.87
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3

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Diagram 2.4; Wiring of Reed Switch
N/O Contact SPDT Contact
Table 2.5; Electrical Data and Operational Limits
Maximum Voltage: 240 VAC
Maximum Current: N/O: 1.5 A
SPDT: 0.8 A
Maximum Power Dissipation: N/O: 50 VA
SPDT: 30 VA
Environmental Protection: IP 65 (IEC 259)
(Equal to NEMA 4)
UL recognized, CSA approved

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FM Revision 3/24/04
3.0 __Principle of Operation
The KOBOLD VKA flowmeter has a spring-loaded float which slides within a cylindrical
measuring tube. Our patented process for achieving viscosity compensation hinges on
the use of the nonlinear behavior of the float spring in combination with a unique orifice
integral to the float itself. A large amount of medium density compensation is provided
simultaneously.
Should flow monitoring be desired, limit switches may be added to the device easily.
Permanent magnets on the float actuate an electrically isolated, sealed contact (reed
switch) mounted on the outside of the instrument housing. This arrangement guarantees
hermetic separation of the medium and the electrical system. The contact is embedded
within a plastic housing to prevent damage to the contacts by mechanical action or
aggressive atmospheres. The contact housing is mounted in slides to enable set point
changes to be effected.
The flowing media raises the float against the spring force. When the magnetic field
reaches the contact reeds of the reed switch, the contact actuates. As the flow increases,
the float rises until it reaches its stop. This prevents the float from going beyond the
contact range of the magnetic switch, i.e., the contact remains activated. The result is
bistable switching without a latching relay is achieved.
The magnetic field may be used to couple to an external (i.e., hermetically separated)
indicator. This configuration provides clear indication, even with dark media.
The magnetic field and the indicator are so designed that response to sudden surges in
flow is almost immediate.
4.0 __Installation Instructions
CAUTION: For safety reasons, please read the cautionary information located at
the end of the manual, before attempting installation.
4.1 - Mounting
1. The VKA switch may be mounted in any orientation without effecting accuracy.
No vertical flow down orientation for units with an indicator.
2. The medium must flow through the instrument from inlet to outlet. The inlet
fitting can be identified as the fitting where the float rests in a no flow condition.
Additionally, the flow direction arrow on the meter body points from inlet to
outlet.
3. The medium must not contain any solids or contaminants prone to precipitate

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FM Revision 3/24/04
out of solution and deposition on the instrument's inner walls. This would
prevent proper operation of the device. Unclean media should be filtered
upstream of the VKA. KOBOLD offers a magnetic/membrane filter for such
purposes (Type MFR).
4. Do not install the meter on large masses of ferritic materials or in areas where
strong electric fields are present, as this will hamper proper operation of the
reed contact.
4.2 - Adjusting the Set point for Increasing Flow
The set point may be adjusted as follows:
1. Loosen the hold-down screws on the reed contact housing.
2. Slide the contact upwards along its rail until it reaches its stops.
3. Open the medium feed line and set flow to desired volume.
4. Slide the reed contact downwards until the contact actuates.
5. Tighten the hold-down screws.
4.3 - Adjusting the Set point for Decreasing Flow
Adjust the set point as follows:
1. Loosen the hold-down screws on the reed contact housing.
2. Slide the contact downwards (toward inlet) along the rail until it reaches its
stops. The reed contact will be actuated at this point.
3. Open the feed line and introduce flow until the reed contact de actuates, then
lower the flow value to the desired minimum.
4. Slide the contact upwards (toward outlet) until the reed contact actuates again.
5. Tighten the hold-screws.

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FM Revision 3/24/04
4.4 - Contact Protection
Maximum values of current and voltage must not be exceeded on the reed switch. When
driving inductive or capacitive loads, we recommend protecting the contact as dia-
grammed below. If continuous load values exceed contact rating, we recommend the use
of an isolation relay. KOBOLD provides a line of relays for such instances.
Diagram 2.6; Contact Protection

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FM Revision 3/24/04
5.0 __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.
6.0 __Need help with your VKA?
Call one of our friendly engineers at 412-788-2830.