Gurley Precision Instruments, or GPI, is an ISO-9001 certified U.S. manufacturing company based in
Troy, New York.
History
Gurley Enterprise was established by
William Gurley and Lewis E. Gurley in 1845, brothers who were both alumni of
Rensselaer Polytechnic Institute
Rensselaer Polytechnic Institute () (RPI) is a private research university in Troy, New York, with an additional campus in Hartford, Connecticut. A third campus in Groton, Connecticut closed in 2018. RPI was established in 1824 by Stephen Van ...
. In 1885 Gurley started making Hydrologic equipment and in the early 1900s acquired many new fields including paper testing equipment and thermometers. During World War II Gurley won the
Army-Navy ‘E’ Award for their contribution to the war effort. In the 1950s the company started producing optical encoders. During the
Cold war era, Gurley manufactured
gyroscope
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rota ...
s,
sextant
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celes ...
s,
star trackers,
theodolites, angle dividers, optical positioning systems, and various other precision guidance devices for
guided missiles and for
space launch vehicles.
Teledyne Corporation acquired W. & L. E. Gurley in 1968. In 1993 Gurley was sold again and became Gurley Precision Instruments.
The
W. & L. E. Gurley Building in Troy was named a
National Historic Landmark in 1983.
Units of measurement
GPI has been responsible for the creation of two commonly used units of measure. These units were so named due to the association with the devices used for their measurement.
Porosity
The Gurley second or Gurley unit is a unit that describes
air permeability as a function of the time required for a specified amount of air to pass through a specified area of a separator under a specified pressure. Specifically, it is defined as the number of seconds required for 100 cubic centimeters (1 deciliter) of air to pass through 1.0 square inch of a given material at a pressure differential of 4.88 inches of water (0.176 psi)(ISO 5636-5:2003).
Stiffness
The Gurley unit is a measure of the stiffness of a material. Since the measurement device holds a piece of material vertically and tests the force required to deflect the material a given amount. One Gurley unit is equivalent to one milligram of force
[
Handbook of nonwoven filter media (2007) p. 423]
, however the Gurley unit also implies measurement with this apparatus. A related unit, the
Taber, is highly correlated but uses a different apparatus (manufactured by
Taber Industries) for performing measurements.
References
GPI homepageRelation between Taber and Gurley
Troy, New York
Manufacturing companies based in New York (state)
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