Stow Laboratories Inc.
designs and manufactures
highly accurate industrial temperature measuring systems,
and indicators, electronic and digital thermometers, calibrators,
sensors and accessories,
known as the STOLAB PL SYSTEM (TM).
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You may have also found us as Stow Lab,
Stow Labs, Stolabs, or Stow Laboratories
Founded in 1966, STOLAB designs and manufactures industrial instruments,
primarily the highly accurate PL SYSTEM for temperature measurement and
control. Our products have earned a reputation for reliability, ease of
use, and dependable performance. We are a small company, our phones are
answered by people, not machines. If you need to measure temperature accurately,
would like some application help, further product information, pricing,
and ordering information, please contact us :
phone, fax or e-mail :
If you found us using a search, please let us know which one - thanks.
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7 Kane Industrial Dr
Hudson MA 01749-2976
|As of 1 September 1997, STOLAB has a new phone and fax area code (our
location is unchanged). The new area code is "978" and should work from
1 December 1997, but if it does not work from your area, try the old
(508) area code. The phone companies will get it sorted out eventually.
STOLAB PL SYSTEM (TM)
A unique, patented design by Stow Laboratories Inc.
The STOLAB PL SYSTEM was designed for accurate,
trouble-free, versatile, and reliable temperature measurement in industrial
environments. It is also widely used in laboratories, hospitals, metrology,
power generation, pipelines, and many other fields. Because it was designed
and is manufactured as a complete system, it eliminates many common temperature
measurement errors. PL SYSTEM users can add, replace, and interchange
all system elements : sensors, electronics, switch boxes, sensor cable
extensions, etc., at any time, without loss of accuracy, and without any
need to recalibrate anything. This key feature prevents inadvertent - and
often unrecognized - measurement errors inherent in the use of instruments
and sensors which must be calibrated and used only as "matched sets".
Brief PL SYSTEM specifications :
All PL SYSTEM sensors and electronics are factory compensated/calibrated,
and are delivered complete, ready for use. The main system elements are
Type PL sensors, electronics, and accessories, briefly described below
measurement range is -85C to +200C (-121F to +392F)
the system accuracy is +/- 0.10C +/-0.15%
the system is guaranteed to perform within
the published specifications for two years without recalibration.
Type PL Sensors include a very stable, platinum
resistance temperature detector (RTD) and selected compensating resistors,
sealed in a stainless steel housing. A cable and a connector complete the
assembly. Standard Type PL Sensors are available
in three types of stainless-steel housings (304, 316, and Teflon-coated
316), housing lengths from 3 inches to 24 inches, a choice of two cable
types, and cable lengths from 3 feet to 10 feet. Many other configurations
are available on special order.
Type PL sensors are :
Sensor accessories include switch boxes for
multi-sensor applications, sensor mounting adaptors, and sensor cable extensions.
individually factory compensated, which makes them ten times more accurate
than standard RTD's, and fully interchangeable in the field at any time.
This key feature of the PL SYSTEM means that any number of sensors can
be used at a site, production line, or lab, without having to keep track
of "matched" instrument/sensor sets. Multiple sensors can be used with
an instrument/readout; sensors can be added, interchanged, and replaced
without any loss of measurement accuracy.
rated for continuous use at temperatures from -85C to +200C (or -121F to
+392F), including the sensor cable.
sealed, fully immersible in all gases and fluids compatible with the housing
and cable materials (stainless steel, Teflon, and silicone rubber).
complete with cable and plug, ready to use.
rugged and reliable, with proven long-term stability and reliability.
PL SYSTEM electronics are designed for long-term
stability and reliability. Their unique, patented circuit converts the
sensor reading to a linearized voltage signal, calibrated to 10 millivolts
per degree (C or F). This signal is available for control, recording, and
monitoring, data acquisition, and data logging. It is also used as the
input for digital display if applicable. The circuit eliminates the effects
on the output of series resistances interposed between the sensor and the
electronics, such as the use of sensor cable extensions or connector contact
resistances, even if these resistances are unbalanced and variable. Connectors
and interconnecting sensor cables need not be made from any special materials,
as is the case with thermocouple systems. This key feature eliminates all
errors due to sensor installation and wiring, and allows the use of very
long sensor cable extensions. Computer-matched and tested components are
used in the production of PL SYSTEM electronics to minimize signal noise
and ambient temperature effects.
Standard electronics models include :
Electronics accessories include the PL-100
Calibrator, a compact but highly stable and accurate resistance standard
which simulates the Type PL sensor characteristics at the two standard
PL SYSTEM electronics calibration points: 0.00C (+32.00F) and +100.00C
(+212.00F), The PL-100C can be used to conveniently verify, and if necessary,
reset the calibration of all PL SYSTEM electronics, in the lab, on the
production floor, or in the field.
Benchtop (and rack-mountable), line-powered digital thermometers, the 921
A PL-F/C (for 115 VAC) and the 922 A PL-F/C (for 220 VAC). These
units have a large digital display highly legible in all ambient light
conditions from up to 35 feet, a F/C temperature scale selector switch,
a calibrated analog voltage signal output (10 millivolts per degree, F
or C), a digital BCD output equivalent to the displayed digital information,
all housed in an all-metal, rugged case.
Bench top (and rack mountable), line powered electronic thermometers, the
PL-F/C (for 115 VAC) and the 912 PL-F/C (for 220 VAC). Similar
to the digital thermometers, these models omit the digital display - the
output is the calibrated, linear analog voltage of 10 millivolts per degree
F or C.
Printed-circuit card versions for OEM, test stands, and other built-in
uses, the 954 PL-C and 954 PL-F are powered by +/- 15 VDC
and provide a calibrated, linear analog voltage signal of 10 millivolts
per degree C or F, respectively.
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Some typical applications where the STOLAB PL SYSTEM
is being used successfully are listed below; there are many others.
The PL SYSTEM makes a excellent replacement for :
Process control, manufacturing, QC and QA : monitoring and calibration
of production line thermal baths for thermostats, temperature controls,
bi-metal elements, and thermal switches. Temperature coefficients of crystal
oscillators, transducers, microwave components, etc. Gas and liquid temperatures
in flow stands. Sterilization and fermentation temperature control in the
chemical and pharmaceutical industries. Photo processing. Viscosity measurements
in the production of lubricants.
Pipelines, power generation : Compressor and gas turbine efficiency
measurements, gas and air density monitoring
Metrology : Calibration of thermocouples and thermistors, secondary
temperature standard for field and production use
Hospitals : Servicing and calibration of temperature-sensitive equipment
such as incubators, blood storage units, centrifuges
R & D : product development, automotive, rubber products, microwave
components, crystal oscillators, differential temperature measurement of
heat exchangers, battery temperatures, carburation test stands, environmental
testing, temperature and humidity chamber monitoring and control, time/temperature
recording, boiling and freezing point determinations,
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mercury-in-glass thermometers; it eliminates mercury contamination risks,
and breakage. It allows remote, safe, convenient, and accurate readings,
and has a much higher range and resolution.
thermocouple systems : it is much more stable and accurate
thermistor systems : much wider temperature range, generally more accurate
other RTD systems : compensated Type PL sensors are more accurate and are
All STOLAB products are sold and shipped directly from our factory in
Hudson, MA, USA. Most standard PL SYSTEM items are in stock for immediate
delivery - contact us for current
prices and availability.
We have over twenty five years of experience helping our customers to
apply the STOLAB PL SYSTEM to many different temperature measuring needs.
us to discuss your requirements, and we will help you determine the
best choice of equipment. Listed below are some of the parameters which
may affect the choice :
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What is to be measured (liquid, gas, solid), physical constraints/size
limitations if any. Can the sensor be immersed in, or surrounded by, the
material whose temperature is to be measured?
Maximum and minimum temperature to be measured (i.e., sensor temperature
Desired accuracy of the temperature measurement, either as a percentage
of the reading or as an absolute value (+/- degrees); desired time period
between recalibration/verification of the equipment performance
Response time, i.e. how rapidly does the temperature to be measured change
and how accurately should the sensor track it while it is changing
Number of locations where temperature is to be measured. If more than one,
are these measurements to be taken simultaneously, or can they be made
Distance(s) from the point of temperature measurement to the location of
the electronic display unit or sensor switch box.
Environment for the sensors and the electronics (indoor, outdoor, etc)
Intrinsic safety requirements, if any
"STOLAB", " STOLAB PL SYSTEM", "TYPE PL sensor"
are Stow Laboratories Inc's trademarks
Stow Laboratories Inc reserves the right to make changes
to this publication without notice. This publication is for information
only, it is not an offer to sell; no guarantees of suitability for
a particular use are offered or implied. Receipt of this information does
not constitute a "sales presence" by Stow Laboratories Inc in the recipient's
state or jurisdiction for sales tax or other purposes. Orders for STOLAB
products are accepted only at Stow Laboratories' location in Hudson,
MA, and are governed by the laws of the Commonwealth of Massachusetts.
Copyright 1996-8, STOW LABORATORIES INC, All rights reserved