11164 Young River Avenue Fountain Valley, CA 92708 Page 1
714-799-1616 phone 714-799-4116 fax Revision B: 06/30/20
SEN-410 SERIES
(SEN-411, 412, 413, 414, 415, 417, 418)
MELT PRESSURE/TEMPERATURE TRANSDUCERS
INSTALLATION INSTRUCTIONS
1.0 INTRODUCTION:
The Series 410 Pressure and Pressure/Temperature Transducers use the proven Silicon-on-Sapphire
Technology for direct measurement of pressure without the necessity of using mercury, NaK, or push rods
to isolate the sensing diaphragm from the high temperature environment. The sapphire diaphragm is thicker
and more abrasion resistant than the conventional mercury-filled melt pressure transducers. These
transducers can give the user unprecedented life if proper care is used in installation and removal.
In the plastics industry, 85% of all replacements are the result of improper handling of the transducers. The
other 15% is a result of wear-out. If YOU, the user, will take the time to read and heed these instructions,
you should get many years of satisfactory use out of these solid-state Sapphire Melt Pressure Transducers.
2.0 IMPORTANT WARNING:
2.1 Do not remove the protective plastic cap until the transducer is ready to be installed.
2.2 The transducer mounting-well machining must be checked before installation of the transducer. (Mounting
well must be free of frozen plastic or degraded polymer).
2.3 Transducer should only be removed or installed when the extruder is near operating temperature and there
is no pressure in the barrel. Failure to do so can result in cross-threading and side-force pressure on the
sensor tips, leading to damage and/or improper functioning. No transducer can work properly with a
pinching force on the diaphragm.
3.0 INSTALLATION:
3.1 Prior to installing the transducer into the mounting well, the machining tolerances of the well must be
confirmed. Mounting wells that are out of tolerance are the single most common cause of premature
transducer failure. The use of a mounting well Gage plug (available from Sensonetics) coated with Dykem
Blue will confirm the concentricity, diameter, and the condition of the 45-degree seat. In high abrasion
applications, it is not uncommon to have a burr form at the inner lip of the mounting well which can ruin the
diaphragm.
3.2 The transducer tip should be recessed 0.015" (.3-. 4mm) from the extruder bore. As the extruder barrel
wears, the 0.015" recess will be reduced until the transducer diaphragm is flush with the bore of the
extruder. This is a very precarious position for the transducer. Shims are available from the factory, which
seat on the 45-degree cone and act as a spacer; backing off the transducer diaphragm from the extruder
barrel bore.
3.3 It is not the purpose of the spacer shim to act as a gasket; that is taken care of by the 45º-angle shoulder on
the transducer seat. Spacer shims are seldom required, but they are required when the well depth is less than
design specification due to:
a. Barrel wear.
b. Reaming & Tapping wear.
c. Improper machined depth (even in new machines).
3.4 It is important that the tip of the melt pressure unit be slightly recessed in the barrel, but flush downstream.
This prevents age in the screw area and prevents disruption of laminar flow in the die area.
3.5 The transducer threads should be coated with a high temperature anti-seize compound such as NEVER
SEEZ by Bostik or C5A by Felpro. Liberal use of anti-seize compounds will reduce the chances of galling.
