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Series 3 L…10 L are a new generation of transducers from KELLER which feature smaller
capsule dimensions and a crevice-free diaphragms. KELLER’s expertise in laser welding very
thin materials enables the production of a line of transducers with a crevice-free media interface
while improving on performance and long-term stability.
Each transducer undergoes extensive automated testing and is supplied with calibration data
which includes sensitivity, linearity, initial zero offset and thermal effects over the compensated
temperature range. This provides the user with the information required to ensure performance
within specifcations.
The 3 L…10 L transducers feature floating O-ring mounting to avoid errors which can be caused
by mechanical stresses imparted to the transducer housing and ensures performance within the
specifcations. The transducer housing encases the piezoresistive silicon pressure sensor and a
small quantity of oil, the latter of which is required to effciently transfer the pressure exerted on
the media-isolation diaphragm to the silicon pressure sensor.
The type of oil is most typically silicone but other oils are available for special applications where
silicones are not allowed.
With the laser welded technology, transducers having diameters as low as 9,5 mm can be
realised. As can be discerned from the below chart, the lower the pressure ranges are available
in only the larger, i.e., Ø 19 mm diameter, due to the inherent increase in diaphragm stiffness as
the diameter is reduced.
Also note from the chart the lengths of the “L” vs. “L HP” designs, e.g., Series 6 L and 6 L HP,
wherein the 6 L HP is 3,5 mm longer than the 6 L in order to accommodate the thicker glass
feedthrough required to contain the higher pressures.
 

Type

Dimensions (mm)

Ranges (bar)

Version

3 L

Ø 9,5 x 4,2

20...200

abs.

4 L

Ø 11 x 4,2

10...200

abs.

5 L

Ø 12 x 4,5

10...200

abs.

6 L

Ø 13 x 4,5

20...200

abs.

6 L

HP Ø 13 x 8

200...1000

abs.

7 L

Ø 15 x 5

10...200

abs. / gauge (< 50 bar)

7 L HP

Ø 15 x 8

200...1000

abs.

8 L

Ø 17 x 7

0,2...200

abs. / gauge (< 50 bar)

9 L

Ø 19 x 5

0,2...200

abs. / gauge (< 50 bar)

PD-9 L

Ø 19 x 15

0,1...50

diff. / nass-nass

10 L

Ø 19 x 15

0,1...100

abs. / gauge

10 L HP

Ø 19 x 15

200...1000

abs. / gauge (< 50 bar)

PD-10 L

Ø 19 x 26

0,1...50

diff. / nass-nass