A20 SERIES PRESSURE
MURPHYGAGES) AND SWICHGAGES'
Modeled
after
the
time-and-work-tested,
steel
case
SWICHGAGEâ , the A20 series offers the same accuracy and
durable dependability as the original instruments, also options
for ungrounded systems and corrosive environments. These
SWICHGAGESâ , have the front face, adjustable and visible
limit contacts that act as switches upon contact with the gauge
pointer: wiring is easily completed on the integral, molded
terminal block; Environmentally Sealed models do not require
oil seal; micro-switches can be added for alarms or to provide
a snap-action SPDT SWICHGAGEsâ
Applications: For situations that require accurate gauging of
critical pressures that cannot be constantly watched by
personnel, the A20 pressure series monitors and can alarm
and/or
shut-down
equipment:
on
Energy,
Agriculture,
Industrial, Construction, or Marine installations.
STANDARD SPECIFICATIONS :
(See also OPTIONS LIST)
Dial: 2" (50.8 mm), white on black, psi & kPa
Case: 2-3/64" (50.99 mm). black, Lexan' 500/glass filled.
Mounting Hole: 2-1/16" (52.4 mm)
Mounting Panel Thickness: 1/8" (3.2 mm) max.
Mounting Bracket: included
Bezel: Polished SS: non-glare black optional
Gauge Connection: 1/8-27 NPTM
Sensing Element: Diaphragm of beryllium copper
Gauge Accuracy: 2%, In the Operating Range (mid 1/3 of
scale)
Over Pressure: Dial scales 0-15 psi (0-103 kPa) thru 0-200 psi
(0-1.38 MPa) withstand up to twice scale; 0-300 psi
(0-2.07 MPa) scale. to 500 psi (3.45 MPa) max.
SWICHGAGE' Contacts: SPST: pointer and limit contact:
N.C. when the low limit is met N.O. when pointer
operates above limit Contact Area: pointer is nickel
silver: limit contact is silver: current carrying areas are
gold flashed. Contacts have patented self-cleaning
motion to ensure electrical continuity.
Contact Rating: 2 A @ 30 VAC/DC
Limit Contact Adjustment: 40% of scale by Allen wrench
Wiring Connections: molded terminal block. 4-40 screws
Shipping Weight: 8 ozs. (23 kg)
Bulletin A20P-7973
Revised 12-30-81
Catalog Section 05
Class (R)
A20 Pressure SWICHGAGESâ
Accurate, Visible Gauging &
Integral, Adjustable Limit Contacts in
one instrument.
Polycarbonate/Glass
case
for
corrosive
atmospheres
and
ungrounded electrical systems
· Case can be Environmentally Sealed
Also available as a MURPHYGAGEâ or
with a micro-switch for Alarm Before
Shut-down
MODELS in the A20 Series of Pressure Instruments:
MODEL
DESCRIPTION
STANDARD
A20-PG
MURPHYGAGEÒ
A20-P
std. SWICHGAGEÒ
A20-PV HL
pressure/vacuum. Hi & Lo
with OPTIONS
A20-PG ES
MURPHYGAGEÒ . Environmental
Seal
A20-P ES
SWICHGAGEÒ , Environmental
Seal
A20-P HL
High & Low contacts
A20-PK
Knob adj. (1 A @ 125 VAC)
A20-PK ES
K model, Environmental Seal
A20-PK HL
K model, High & Low contacts
A20-P ABS
Alarm Before Shut-down
A20- EO
SPDT Snap-Action SWICHGAGE'
OPTIONS LIST:
Gauge Only: Order a MURPHYGAGE
Environmentally
Sealed:
An
internal
silicone
lung
compensates for ambient temperature changes, silicone O-
rings seal the case. For corrosive atmospheres order
models with the "ES" designator. (More Info. on Bul. PA25-
7972)
High & Low Contacts: For applications where both high
and low pressures are critical, order models with the
"HL" designator. Acts as SPDT switch see wiring
diagram.
K Models: Nylon knob adjustment on front contact models
allows SWICHGAGEâ contact rating. 2 A @ 30 VAC/DC
or 1 A @ 125 VAC.
Alarm Before Shut-down: std. SWICHGAGE includes a
micro switch, preset at the factory to switch for alarm
before the front low contact Is made: see Contact Setting
Chart, wiring diagram, and description on this bulletin.
Snap-Action SWICHGAGE: A20-EO has an internal SPDT
micro switch only. for three wire control: can be wired to make
or break a circuit. See description., switch set point and wiring
diagram on this bulletin
