Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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A STEAM TRAP ARRA~IGEME~T COMPRISING A STEAM TRAP
AND A F~UID F~OW M~NITOR IN A STEAM FLOW LINE
This invention relates to fluid flow monitors for
use in steam flow lines, and to a steam trap arrangement
comprising a steam trap and such a fluid flow monitor.
Commonly used fluid flow monitors rely on observa-
tion of the conditions in the flow line upstream or down-
stream of the steam trap, through a glass window (a so-
called sight glass) and skill is required to interpret whatis observed. Furthermore the glass frequently becomes
dirty making observation difficult or impossible.
~n aspect of the invention is as follows:
~ steam trap arrangement comprising a steam trap
and a fluid flow monitor in a steam flow line which includes
the steam trap, the monitor comprising a chamber having an
inlet and an outlet, the outlet connected to an inlet of the
steam trap so that flow of steam to be trapped is via the
monitor, said chamher having a receptacle region for conden-
sate, the monitor further comprising a single baffle mountedin the chamber between the inlet and the outlet such that
the baffle extends into said receptacle region and such
that a steam flow induced pressure drop at the outlet of
the chamber, when the arrangement is operatively connected
in a flow line, results in a rise in the level of the
collected condensate on the outlet side of the baffle with
a corresponding fall in the level of the collected conden-
sate on the inlet side of the baffle, the monitor further
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comprising means for ascertaining a change in the conden- -
sate level to a predetermined extent brought about by the
steam flow induced pressure drop at the outlet resulting
from loss of steam at the trap, said change ascertaining
means comprising a single electrode extending into said
receptacle region of the chamber in which condensate can
collect, and means defining an electrically conductive
area exposed to the collected condensate, said electrode
being electrically insulated from said conductive area
means and positioned with respect thereto such that when
the arrangement is operatively connected in a flow line a
change in condensate level to a predetermined extent
brought about by a pressure drop at the outlet breaks an
electrically conductive path from the electrode via the
condensate to the electrically conductive area.
A fluid flow monitor as now proposed cannot
become obscured by dirt, does not have to be fitted in
line of sight, and requires no skill in use. Moreover the
particular monitor herein proposed is of simple and
compact design.
For a better understanding of the invention and to
show how the same may be carried into effect reference will
now be made, by way of example, to the drawing accompany-
ing this specification in which:
Figure 1 is a schematic sectional side view of a
first form of fluid flow monitor illustrated in a first
operating condition,
Figure 2 is a similar view of the monitor of
Figure 1 b~t illustrated in a second operating condition,
Figure 3 is a schematic sectional side view of a
second form of a fluid flow monitor illustrated in the same
operating condition as the first form of monitor is shown
in Figure 1, and
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Figure 4 is a schematic sectional side view
of the monitor o~ Figure 3 but shown in the same
operating condition as is the ~irst ~orm in Figure 2.
The ~luid ~low monitors o~ the Figures each
include a chamber.l having an inlet 2 and an outlet ~
3 whereby the chamber can be connected in a steam .i
flow line to serve as a receptacle ~or condensate 4. ~$
In the.detector of Figures l and 2 the inlet and outlet
are in the upper part of the chamber so that condensate - ~
can collect in the lower.part of the chamber, this "t
detector being ~or insertion in a horizontal pipe run.
In the detector o~ Figures l.and 2 there is between the `~
inlet 2 and the outlet 3 ~ single baffle 5 that depends
~rom the upper wall of thè chamber l into the chamber part '`.7
in which the condensate can collect, this baffle 5
terminating short of the bottom of the chamber and .
having a 1;hrough aperture 5A at substantially the same
level as t;he level o~ the..lnlet andoutlet 2 and 3.
In the ~orm shown the baiile 5 i.s vertical but it could . ~,
be inclined, for example towards; the inlet 2 ~n the
direction ~rom its top edge towards its~ree lower edge. ~.
In the wall oi the part of the chamber l in
which condensate can collect there is a single
electrode 6 supported in an electrically conductive
~ounting 7 so as to be electric~,lly insulated from the ii'
mounting 7 and.henoe also from the remainder of the chamber ~;
l. The electrode 6 projects into.the interior o~ the ~^3,
chamber, at a position, in that part ~ the cham~er in which
condensate can collect, that is between the ba~le 5
30 . and the.inlet 2, and that is below the level of the
inlet and outlet 2 and 3.
The monitor o~ Figures 3 and 4 has its inlet
2 at the top of the chamber l and its outlet 3 at the
bottom o~ the chamber l. This monitor is ~or insertion
in vertical pipe runs, the outlet 3 being connected
to an upright extension duct 3A the upper end of which
dbtermines the level to which the condensate 4 can collect
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in the chamber 1. This duct 3A is within a
single upright bai'~le 50 i'ormed by a casing standing
on the bot~om o~ the chamber 1 and containing the duct
3A with clearance between the duct and the casing.
A part of the upright wall o~ the casing terminates, at
8, short o~ the bottom o~ the chamber 1 and the casing ~^
50 has a through aperture 50A in its otherwise
closed upper end. :i
.As in the case of the monitor of Figures 1 and 2, 3
in the monitor of Figures 3 and 4 there is, in the wall
oi the part of the chamber 1 in which condensate `~
can collect, a single electrode 6 and mounting 7
as described above, the electrode projecting into the
interior of the chamber 1 at a position that is below
the upper end of the outlet extension duct 3A. The
- electrically conductive mounting 7 is exposed to this part
o~ the interior of the chamber.
In each ~orm the electrode 6 and mounting 7 are ~l
in circuit with a power source, such as a dry battery, and `,¦
indicator lights 9 in a control box 10, the circuit being
such that one of the lights (which can be a green light)
is illun~nated i~ the clrcuit is~ completed because the
electrode is submerged in condersate giving an electi~ally
conductive path ~rom the electra,de to the mounting via
the condensate, whereas another light (which can be red)
is illuminated if the electrode is not submerged and the
path just mentioned is therêfore brokenl.
It will be appreciated that the control box~10
does not have to be permanently connected to the electrode
6 and its mounting 7 o-~ any one monitor, and that one
control box can be connected to any number o~ monitors
in turn to test whether condensate is present to
electrode level. Alternatively, several monitors
can have their electrodes and mountings connected to one
centra~ control panel.
Alternative means such as a powered meter can be
used to check whether there is an electrically conductive
patb between the electrode and its mounting.
38~
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A monitor at an inaccessible position can have
~lying leads permanently attached and termina-ting at a
more accessible point.
Figure 1 illustrates the monitor as i~ in use
w~th its outlet 3 connected to the inlet o~ a steam
trap so that the ilow of steam to be trapped is via the
monitor. As shown in ~igure 1, when the steam trap
is shut condensate is present in the chamber 1 to the
same level (in line with the inlet ? ) on either side -
of the ba~le 5 and the electrical circuit including ~
the electrode 6 and its mounting 7 is completed via ~j
this condensate. ~ 1
A small amount oi steam will be condensing in the
body o~ the steam trap and in the fittings between the ~3
trap and the monitor. To make up this loss a similar ~
amount of steam can pass through the aperture 5A near the ,
top o~ the baifle 5 without disturbing the condensate levels
on either side of the bai~le. l¦
If more condensate ilo~vs to the trap, causing it ~l
to ope~, the monitor chamber becomes ~looded. Even if
there is only a dribble o~ condensate ~lowing through the
trap, this is sui~icient to keep the level in the
monitor chamber above the electrode.
I~, however, more steam passes through the trap ;~
than is normal due to condensation losses (i.e. steam is à
ieaking away), a pressure drop is induced at the
monitor chamber outlet 3 by this flow of steam which results ;
in a rise in level of the collected condensate 4 on ~`
the downstream (outlet 3) side of the bà~fle 5 and a ~.
corresponding iall in condensate level on the upstream
~inlet 2) side o~ the ba~fle 5, condensate flowing
under the baffle 5 from the inlet side to the outlet side. ;~
When the condensate level on the inlet side drops below
the level o~ the electrode (Figure 2) the electrically
conductive path ls broken and there is thus obtained
at the control bog an indication o~ the occurrence
o~ the pressure drop. In each case there ~s thus obtained
an indication o~ the le~k that has brought the pressure drop ~ i
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about. Thus the flow of steam through the steam line
to the trap can be monitored.
The water level upstream of the baffle 5 is
depressed to below the electrode 6 even if a quantity of
condensate is passing together with the leaking steam.
For 'qxample, if lOOkg/hr of condensate is being discharged ~'
but the steam trap is stuck open so that it is passing
this load and leaking say 20 kg/hr of live steam, then ;~,
the water level in the monitor would be depressed and the ~,
pressure drop, and hence the leak, would be indicated.
As is illustrated in Figures 3 and 4, the `~,
monitor herein illustrated operates in a similar manner '
to that illustrated in Figures 1 and 2. The outlet 3 is '5
connected to the ~nlet of a steam trap so that the flow
of steam to be trapped is via the monitor. As is shown
in Figure 3, when the steam trap is shut condensate is ,~
present in the chamber 1 to the same level (in line with the -~
inlet of the extension duct 3A) on either side of the '~
baffle 50 and the electrical circuit including the
electrode 6 and its mounting 7 is completed via this ~`
condensate. ` ;,~
To make up the loss of t,he small amount of steam
that will be condensing in the body of the steam trap
and in the fittings between the trap and the monitor ~3
~5 ,a similar amount o~` steam can pass through the aperture
50A and into the duct 3A without disturbing the ~,
condensate levels on either side of the baffle 50.
Pressure drop induced at the duct 3A by flow o~ steam
th~t is leaking away results, as shown in Figure 4, ;
in a rising level of the collecting condensate on the
downsteam side of the baffle 50 (i.e. within the baffle
50)and a corresponding fall in condensate level on the
upstream side of the baffle (i.e. outside the baffle~,
condensate flowing under the baffle 50 from the inlet
side to the outlet side where the baffle terminates,
at 8, short of the bottom o~ the chamber 1. ,
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In a modified form of the monitor of
,
Figures 3 and ~ (not illustrated) the upright extension
duct is at one side o~ the chamber and the.single baffle
is between the duct and the other side of the chamber, I
the baffle comprising an upright part depe~ding from a pa~titicn ~'
that is above the upper end of the extension duct, the
upright part terminating short of the bottom of the part
of the chamber in which condensate collects, there being
a clearance between the upright part/partition `,
and the duct, ahd the partition having a through ~'.
aperture. Operation is as described ~or Figures `:
3 and 4.
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