About Pressure Gauges and Pressure Gauge Manufacturers Including:
Air Pressure Gauge, Digital
Pressure Gauge, Fuel
Pressure Gauge, Oil
Pressure Gauge & Water
Pressure Gauge.
Pressure gauges are instruments that are designed
to measure the pressure of a gas or liquid. Pressure gauges monitor and indicate
the internal pressure and/or the vacuum of vessels or systems, especially
those having dynamic working characteristics that require constant monitoring.
Standard pressure gauges typically utilize a Bourdon tube, a sensing element for
measuring pressures 15 psi or more. Bourdon tubes are spirally wound
or C-shaped and are usually made of stainless steel or copper alloy.
When a pressure change occurs, the pressure gauges flex and produce a rotational movement,
causing the gauge indicator to move. A diaphragm seal or gauge isolator
can be used to prevent the Bourdon tube from coming into contact with
the process material, if the tube and material are not compatible.
Pressure gauges vary in style, size and wetted parts material, depending
on the application. Display types include graphical and video displays,
digital readouts or analog meters and needles. The scale of an analog
pressure gauge can display one or two units on the same face (e.g. psi,
kPa, Bar, inches Hg, cm Hg). Some pressure gauges have pointers that can be adjusted
to zero by turning a screw or a knob. Adjustable or stationary set hands
are separate pointers that indicate a preset pressure. Some pressure
gauges do not display a measure of pressure. Instead, they monitor pressure
and send an electronic output signal for any required changes in the
system. Throttling devices, which are used to decrease the effects of
pressure pulsation and/or vibration on pointer movement, include throttling
screws, pulsation dampeners, elastomeric bladders, pressure snubbers
and needle valves. Pressure gauges can also be equipped with electric
contacts to turn on signal lights, sound alarms or operate a pump or
valve.
There pressure gauges have a wide variety of industrial applications in which
the pressure
gauges are utilized. Specialty tanks, such as fire extinguishers and
medical gas cylinders use pressure gauges. Liquid filled gauges are utilized
in nitrous systems on nitrous bottles or solenoids. Gauges made of stainless
steel can be used in applications that have strict sanitary requirements
and are capable of withstanding high pressure cleaning. Some pressure
gauges are specifically designed for use in high purity semiconductor
gas and liquid applications with a range from vacuum to 6,000 psig. Pressure
gauges are essential for applications in which the accurate functioning
of a vessel or system directly depends on the accuracy of the gauge reading,
such as in pesticide sprayers.
The accurate selection of pressure gauges requires the consideration
of some key factors, including the gauge process, range, environment,
accuracy, dial size, connection and mounting needs. Compatibility of
the wetted parts of pressure gauges, including the Bourdon tube and
socket, with the process material is essential, as corrosion might otherwise
occur. Liquid filled pressure gauges or gauges that are internally dampened are
better choices for applications in which the gauges would be subject
to pulsation and vibration. It is recommended that the normal operating
pressure be confined to 25-75% of the scale, no higher than 50%, if pulsation
is present. Dial size is typically determined by readability requirements,
space limitations and required gauge accuracy. Pressure gauges connections
should be selected with the following in mind: process pressures, gauge
size and weight, space limitations and leak integrity. Gauge performance
can be affected by ambient temperature, air-borne particulate, condensation,
humidity, water and chemicals.
Types of Pressure Gauges
- measure any pressure above
vacuum (zero pressure).
- measure the air pressure of pneumatic equipment.
- , also called "sea level gauges," are
the most commonly used gauge. Ambient gauges are preset to read zero
pressure
at standard atmospheric pressure (14.7 psi).
- measure both pressure and vacuum.
- , also referred to as "general purpose gauges" or "equipment
gauges," are low-cost measuring instruments designed for applications
that do not have severe conditions. Commercial gauges may be ruggedly
constructed but are not typically economical to repair.
- provide the relative pressure between
two measurement points. An indication of differential pressure only
occurs when one pressure is higher or lower than the other.
- are industrial standard gauges, typically battery-powered,
which use a digital display rather than an analog dial display. Digital
readouts are typically easier to read and provide a greater accuracy
than dials.
- are instruments that indicate the pressure of
the fuel supply to the intake manifold in a combustion engine.
- have heavy-duty sensing elements and case designs
and higher accuracy requirements than general purpose gauges, are built
for extended life and are designed for harsh, corrosive environments.
- can be filled with various fluids, such as silicone
oil, mineral oil and glycerin. The liquid fill provides protection
to internal components of the gauge in severe environments in which
the gauge may encounter excessive vibration and pulsation.
- are designed to accurately measure pressures less
than 15 psig using a capsule sensing element.
- are instruments that measure
and display the pressure of the oil circulating in any lubricating
system.
- are extremely sensitive and highly accurate
instruments that are used in applications which demand precision and
consistent results, such as instrument shops, gauge repair and calibration
shops and testing laboratories.
- are made from corrosion resistant material to meet the
demanding heavy-duty operating and construction requirements of the
chemical and petroleum industries. Process gauges are also designed
to fulfill the exacting accuracy and service life needs of a variety
of process applications.
- have a scale that is compressed at either one or both
of its ends.
- indicate negative atmospheric pressure or the degree
of rarefaction below atmospheric pressure.
- are designed to determine and monitor the pressure
of any system that uses water.
Pressure Gauges Terms
-
A thin walled elastic tube of metal that is flat and formed into a circular
shape, which tends to straighten in response to increases in pressure
and is fixed to a pressure recording or indicating device such as a gauge
- The part of the gauge that
works with the dial to indicate the pressure level
- A
way of making an modification in indication with an adjustable needle
with the change being the same over the whole scale
- The insertion
of a plug in wall of the gauge that vents when there is an element leak
to prohibit excess pressure build up in the case
- The highest pressure
a gauge can maintain with no apparent alteration in accuracy
- A periodic pressure swell
- The highest difference
from any two or more successive indications for identical working conditions
and applied pressure
- The apparatus that limits
the flow of fluid between the pressure element and the source of pressure
- The scale of this gauge
is compressed at either one or both ends
- The part that firmly fixes
the window to the case
- The highest pressure
that the pressure element can hold the pressure, anything above this it
will not be capable of holding pressure
- The markings on the dial comprised
of gradations, related numbers and units of measure
- An apparatus for the reduction
of the effect of pressure variations and surges
- The major supporting
element of the pressure component assembly that the elastic component
is fixed
- The alteration
of pressure indication that is caused by the difference of temperature
in the components from the temperature that they were calibrated at
- Any element of a gauge
that comes in direct contact with pressure media
- A clear component made of
glass or plastic closing the front of the case