Applications The level limiter NK10 is applied into heat and process engineering plants to ensure that the lowest permissible level is not fallen below. The instrument meets the requirements of DIN 4574 as limiter. This series’ instruments are structural tested and have received the DIN registration number / prototype test mark of DIN CERTCO Gesellschaft für Konformitätsbewertung (company for validation of conformity). Construction and Operation The floater of the level limiter is located in the fluid filled vessel (expansion vessel). The float moves when the level changes. This movement is transported directly to a microswitch by the float rod. The float rod is sealed by metal bellows and its centre of rotation is outside of the pressure chamber. A test button is located outside the pressure chamber to enable a function test acc. to DIN 32728 without lowering of level. If the test button is pressed the floater is moved against its buoyancy. If the instrument is used as level limiter, a locking and unlocking mechanism acc. to DIN 32728 need to be installed into the subsequent electrical control. This safety device must meet demands of DIN 57116 / VDE 0116.

1. 28.2.08DB_GB_NK10.fm
Applications
The level limiter NK10 is applied into
heat and process engineering plants to
ensure that the lowest permissible level
is not fallen below. The instrument
meets the requirements of DIN 4574 as
limiter.
This series’ instruments are structural
tested and have received the DIN regi-
stration number / prototype test mark of
DIN CERTCO Gesellschaft für Konfor-
mitätsbewertung (company for validati-
on of conformity).
Construction and Operation
The floater of the level limiter is located
in the fluid filled vessel (expansion ves-
sel). The float moves when the level
changes. This movement is transported
directly to a microswitch by the float rod.
The float rod is sealed by metal bellows
and its centre of rotation is outside of the
pressure chamber.
A test button is located outside the pres-
sure chamber to enable a function test
acc. to DIN 32728 without lowering of le-
vel. If the test button is pressed the
floater is moved against its buoyancy.
If the instrument is used as level limiter,
a locking and unlocking mechanism acc.
to DIN 32728 need to be installed into
the subsequent electrical control. This
safety device must meet demands of
DIN 57116 / VDE 0116.
Functional Scheme
Main Features
• Temperature resistant up to 400°C
• Material in contact with medium of stainless steel
• Double wall metal bellows of stainless steel
• Varnish heat resistant
* in reference to density 1kg/dm³
Welded
socket
Float rod
Metal bellows
Test button M16x1.5
connection
Counter flange
Lever Microswitch S1
Float
10N
NK10
Level Limiter

2. Specifications
Electrical Connection
Variants 10N80, 10N65, 10NS80, 10NS90
Max. operating pressure 16 bar
Max. medium temperature 400°C
Perm. ambient temperature 70°C
Variant 10N65/10
Max. operating pressure 10 bar
Max. medium temperature 350°C
Perm. ambient temperature 70°C
For all variants
Max. load data 250 V, 6 A ohmic resistance
Electrical connection internal connector bloc
Protection class IP55 acc. to DIN EN 60529
Specified minimum density rho = 0.6 kg/dm³
Switching hysteresis approx. 6 mm
Mounting position horizontal
For all variants with 2 micro switches
Switching point difference max. 30 mm
at surface of medium depends on density of medium
Materials
Float system stainless steel 1.4301
Metal bellows stainless steel 1.4541
Welded socket St. 35.8
Flange 1.0425 (H II) resp. 15 Mo 3
1 Microswitch 2 Microswitches
Test button
Test button

3. Dimensions (all units in mm unless otherwise stated)
Mounting
Variant 10N80 NK102
The instrument is desinged
with a mounting flange acc. to
DIN flanges - DN 80 PN 25.
The float must be able to move
freely in vertical direction!
Mounting
Variants 10N65 NK101
10N65/10 NK103
The instrument is desinged
with mounting flange with con-
nection dimensions acc. to
DIN 2501.
Connection dimensions
10N65 - DN 65 PN 25
10N65/10 - DN 65 PN 16
The float must be able to move
freely in vertical direction!
Mounting
Variants 10NS80 NK104
10NS90 NK105
The welded socket is welded
into the expansion vessel acc.
to DIN 4754. Regard the moun-
ting position.
The float must be able to move
freely in vertical direction!
Variants
Var.: Size A Size B Size C Size D
10NS80 220 365 82.5 77.5x77.5
10NS90 250 395 88.9 90x90
Variant
PN25 8 x Ø18
PN16 4 x Ø18
18 resp. 22

4. Technische Änderungen vorbehalten • Subject to change without notice • Changements techniques sous réserve
Fischer Mess- und Regeltechnik GmbH • Bielefelder Str. 37a • D-32107 Bad Salzuflen • Tel. +49 5222 9740 • Fax +49 5222 7170 • eMail: info@fischermesstechnik.de • www.fischermesstechnik.de
Ordering Code
Level Limiter 10N
Type Series
Flange connection acc. to DIN 2527 form E DN65 PN25 . > 65 ..................> 1
Flange connection acc. to DIN 2527 form E DN80 PN25 . > 80 ..................> 2
Flange connection acc. to DIN 2527 form E DN65 PN16 . > 65/10 ..................> 3
Welding connection - 82.5 mm............................................ > S80 ..................> 4
Welding connection - 88.9 mm............................................ > S90 ..................> 5
Switching Section
1 Microswitch .............................................................................. > K1 .......................................................> 1
2 Microswitch .............................................................................. > K2 .......................................................> 2
00 0000NK10