Ashcroft DURALIFE 1009 설치, 운영 및 유지보수 매뉴얼 - 페이지 17
{카테고리_이름} Ashcroft DURALIFE 1009에 대한 설치, 운영 및 유지보수 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. Ashcroft DURALIFE 1009 20 페이지. Pressure gauge
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tions must pass before they reach the bourdon
tube. The dampener reduces the magnitude of
the pressure pulse thus extending the life of
the Bourdon tube and movement. This reduc-
tion of the pressure pulsation as "seen" by the
pressure gauge is generally evidenced by a
reduction in the pointer travel. If the orifice is
very small the pointer may indicate the aver-
age service pressure, with little or no indica-
tion of the time varying component of the
process pressure.
Commonly encountered media (e.g. – water
and hydraulic oil) often carry impurities
which can plug the orifice over time thus ren-
dering the gauge inoperative until the damp-
ener is cleaned or replaced.
Highly viscous media and media that tend to
periodically harden (e.g., asphalt) require a
diaphragm seal be fitted to the gauge. The
seal contains an internal orifice which damp-
ens the pressure fluctuation within the fill
fluid.
8.2 Throttle Screws & Plugs – These acces-
sories provide dampening for the least cost.
They have the advantage of fitting completely
within the gauge socket and come in three
types: (a) a screwed-in type which permits
easy removal for cleaning or replacement; (b)
a pressed in, non-threaded design and (c) a
pressed in, threaded design which provides a
highly restrictive, helical flow path. Not all
styles are available on all gauge types.
8.3 Ashcroft Gauge Saver – Type 1073
Ashcroft gauge saver features an elastomeric
bulb that fully isolates the process media
from the bourdon tube. In addition to provid-
ing dampening of pressure pulses, the bour-
don tube is protected from plugging and cor-
rosion. The space between the bulb and bour-
don tube is completely filled with glycerin.
Felt plugs located between the bulb and bour-
don tube are first compressed some amount to
restrict the flow of glycerin through an orifice
and thus provide a degree of dampening. The
greater the compression of the felts the
greater the degree of dampening.
8.4 Ashcroft Pulsation Dampener – Type
1106 Ashcroft pulsation dampener is a mov-
ing pin type in which the restricted orifice is
the clearance between the pin and any one of
five preselected hole diameters. Unlike a sim-
ple throttle screw/plug, this device has a self-
cleaning action in that the pin moves up and
down under the influence of pressure fluc-
tuations.
8.5 Ashcroft Pressure Snubber – The heart
of the Type 1112 pressure snubber is a thick
porous metal filter disc. The disc is available
in four standard porosity grades.
8.6 Campbell Micro-Bean
Micro-Bean is a precision, stainless steel, nee-
dle valve instantly adjustable to changing
conditions of flow and viscosity. A very slight
taper on the valve stem fits into tapered hole
in the body. The degree of dampening is easi-
ly adjusted by turning the valve handle. A fil-
ter is built into the Micro-Bean to help pre-
vent plugging.
8.7 Ashcroft Needle Valves – Type 7001 thru
7004 steel needle valves provide varying
degrees of dampening similar to the Campbell
Micro-Bean but with a less precise and less
costly adjustability. Like the Micro-Bean
these devices, in the event of plugging, can
easily be opened to allow the pressure fluid to
clear away the obstruction.
8.8 Chemiquip
®
Model PLV-255, PLV-2550, PLV-5460, PLV-
5500 and PLV-6430, available with and with-
out built-in snubbers, automatically "shut off"
at adjustable preset values of pressure to pro-
tect the gauge from damage to overpressure.
They are especially useful on hydraulic sys-
tems wherein hydraulic transients (spikes)
are common.
17
®
– Type 1110
Pressure Limiting Valves –