KOBOLD Model NDT
Static Pressure Level Switch
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
NDT_manual_03-04
NDT
Description
The KOBOLD model NDT level switch uses the static pressure principle to monitor the level in
open or vented tanks. The unit operates as follows:
1. The rising liquid level will provide a confined air volume in a user supplied pipe when
the liquid reaches the bottom edge of the pipe.
2. As the liquid level continues to rise, the air trapped inside the pipe is compressed.
3. The switching will occur when the air inside the pipe is compressed to a pressure of 4
inches of water column.
4. The result is a level switch whose switchpoint is fixed at 4 inches above the bottom
edge of the user supplied pipe. This allows the user to set his switchpoint by simply
attaching the appropriate length pipe to the NDT level switch.
Electrical Connections
1
1 = Common
2
3
2 = Normally Closed
3= Normally Open
Technical Specifications
Wetted Parts
Exposed to Liquid:
Exposed to air pocket:
Housing:
Media:
User supplied pipe
NBR, Polyamide
Polyamide
Any free flowing liquid
Fittings:
NDT-2020 1/2” BSP
NDT-2080 1-1/4” Hose fitting
(accommodates 1” SCH 40 or SCH 80)
Switchpoint: 4” above the end of user supplied pipe
Switch Error: ±10%
Temperature Range: 15 to 185°F
Electrical Characteristics:
Switch Type: SPDT
Maximum Rating: 250 VAC, 8 Amp resistive, 1.5 Amp
inductive
Protection: NEMA 4
FM Rev. 3/12/04
NDT
Precautions
The following precautions must be adhered to at all times when using the model NDT flow switch:
• Inspect the instrument for damage upon arrival. Cracked, fractured or
maged instruments must not be put into use since the device is weakened to an
da
unknown extent. If necessary, contact KOBOLD Instruments, Inc. for furthe
gu
idance on making claims for damaged instruments.
• UNDER NO CIRCUMSTANCES must the maximum tolerances of
pre
ssure or electrical loading be exceeded.
• Double check all electrical connections prior to placing the unit into service. Mis-
wired electrical connections can cause immediate and permanent damage
strument.
in
Installation Instructions
1. The model NDT level switch must be mounted above the top of the tank to ensure that
the fluid inside the tank will not contact the switch internals. If the fluid is permitted to
flood the switch internals, the setpoint may be permanently altered or the switch may
otherwise be damaged.
2. The pipe which is to be connected to the switch must be cut such that it extends into
the tank 4 inches farther than the desired setpoint. For example, if the desired
switchpoint is 12 inches below the top of the tank, the pipe should be cut such that it
extends 16 inches into the tank.
otherwise
r
temperature,
to the
3.
If the unit with a threaded pipe connection is being used, a thread sealant suc
PTFE tape should be applied to the threads to ensure an air-tight fit.
4. After all electrical connections are made, ensure that both the housing lid and the
cable gland are tightly secured. This will ensure the watertight integrity of the unit.
5. Both the level switch and the pipe must be rigidly supported to prevent damage to the
pipe fitting and subsequent switch malfunction.
Maintenance
Since the NDT level switch is designed to function without contacting the media, virtually no
maintenance is required. It is recommended that an occasional inspection of the electrical
connections is made to ensure that all connections are tight, and that no corrosion exists.
Additionally, if the process media tends to coat tanks and piping, it is recommended that the
pressure pipe be removed and cleaned on a periodic basis.
Questions
Call one of our friendly engineers at 800-998-1020.
h as
FM Rev. 3/12/04
Loading...