Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention is concerned generally with vari~ble area meters
userul in the measurement Or fluid flow. ~ore particularly~ it is
concerned with a variable area meter unit comprising an enclosure and
a meter tube which can be inserted into a support frame.
Conventional variable area meters typically consist Or a
rectangular, metal framework having top and bottom housings to receive
inlet and outlet rlttings rrom the fluid flow line. The housing also
contains the sealing neans to incorporate the meter tube into the flow
system. Generally, the sealing ~eans consists of a Ea~ket enco~passing
the tube near each end and a seal spindle in the top ho~sing which
rotates to compress the gasket about the ~eter tube. The top and
bottom housing generally are connected by t~o metal panels on opposed
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sides. A front, clear cover and a back, opaque cover a~e provided
between the sides.
Eecau~se Or space require~,ents in ~ost proces~ operations
wherein variable area meters are utilized, the sides of the ~ramework
often are close to the meter tube. Th~s, it ls difficult to insert
and remove the tube from the frameworkO A co~ ~n method is to place
a sm~ll seg~ent Or paper about the tube, grasp the two free ends of the ~ -
paper so that the tube will be held by the paper, insert the tube and
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pclper into the framework, cen~er the tube, r~tate ~he sec~ing spln~l~
to seat the seals ~Ihile supporting the tube in a centered, upright
configuration, removing the pa~er and M nally attaching> the front cover
to the rra~ework.
Several serious problems are apparent from that procedure.
Firstly, it ls very difficult to insert the meter tube within the narrow
~ramework using the fingers alone and the use of the paper greatly
increases the chances Or tube slippage and breakage. Secondly, it is
difficult to center the tube and retaln it in an upright position while
the sealing spindle is being tightened. Furthermore, conventional
sealing spindles cause the tube itself to rotate~ r~hat rotatlon usually
is not constant between different tubes and ~ameworks, and estimates
of an initial tube rotational position are necessary to end with the
indicia cn the tube facing in the forward direction where it can be
read by an operator. Failure to center the tube can result in chipping
Or the tube i~ metal to gLass contact is made.
Other disadvantages are present in conventional units. rfhe
flat surface efrect of the clear, front panel generally distorts the
float image as seen throu~h the front cover, and accurate reading of the
indicated flow rate is difficult. A particular fault o~ conventional
units is their inability to contnol glc~ss fragments from the tube if
t.he tube explode~ Fragments are ~ust as likely to exit from the
front of the rotameter as from the back, thus ~ncreasing the chances of
injury to an operator. Flowmeter tubes are rated at 25Q pounds per
square lnch generally and current standards require them to withstand
1-1/2 times rated pressure. i~o economical method has heretofor been
developed for controll~ng explosions at or higher than the standard
pressures in rotameters which are to have general applicatlons in
the process industries.
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The invention as claimed herein is a variable area
meter insert unit for insertion into a variable area flow meter
frame having a pair of opposed side walls and a top and bottom
housing with means for en~aging a flow meter tube, the inner sur-
faces of the side walls and the top and hottom housin~s defining
a partially enclosea first volume therebetween, the insert unit
comprising a pair of side panels and a pair of end panels ~oined
to the side panels to provide a unitary structure, each of the
end panels having an opening therethrough for receiving a flow
meter tube, the outer surfaces of the side panels and the end
panels defining a partially enclosed second volume which is co-
extensive with the first volume whereby the insert unit is flush
with the meter frame when the insert unit is inserted into the
flow meter frame, the openings in the end panels being positioned
to axially ali~n the flow meter tube with the means in the top
and bottom housing for engaging the 10w meter tube when the insert
unit is flush with the flow meter frame.
The invention as claimed herein is also a variable :.
area meter insert unit for insertion into a variable area flow
meter frame having a pair of opposed side walls and a top and
bottom housing with means for en~aging and establishing fluid
communication with a flow meter tuhe, the inner surfaces of
the side walls and the top and bottom housings defining a par-
tiallv enclosed first volume therebetween, the insert unit
comprising side panel support means~ tube support means attached
at the ends of each of the side panel support means for receiving
a flow meter tube, the outer surfaces of the sidepanel support
means and the tube support means defining a partially enclosed
second volume which is coextensive with the first volume whereby
the insert unit is flush with the meter frame when the insert
unit is inserted into the flow meter frame, means on the tube
support means for positioning a flow meter tube in fluid com-
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munication with the top and bottom housing, pressure relief
means associated with the support means for releasin~ pressure
in a predetermined direction, and viewing means between the side
panel support means.
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m e difficiencies present in current variable area meters are
corrected by the compact, self-contained insert unit of the present
invention, which is illustrated by the following drawings in which:
Figure 1 is an overall view of the insert unit located within the
5v support framew~rk,
Figure 2 is a cross-sectional view of the insert unit and
framework, ;
Figure 3 is a cross-sectional view along line 3-3 of Figure 2, -
Figure 4 is a partial front view of the unit illustrating the
magnification created by the lens portion of the insert unit;
Figures 5 and 6 illustrate valves which can be combin d with the
meter unit; and
Figure 7 illustrates a closure plug which is used on the meter unit
when no valve is used.
lS m e insert unit 10 of this invention is adapted to fit with a
generally conventional, variable area meter framework 30. Framework 30
is fabricated with conventional side members 31 and 32 connecting top
housing 33 and ~ottom housing 34. Bottom housing 34 threadably receives
fluid inlet fitting 36, which is sealed to the housing by seal 48.
Likewise tcp housing 33 threadably receives fluid outlet fitting 35,
which is sealed to the housing by seal 47. Typically, seals 47 and 48 ;;
are 0-ring seals. Bottom housing 34 preferably is formed with a second
threaded openin~ 49, which is adapted to receive valves 51 and 52 or
closure plug 53. Inlet fitting 36 is in fluid communication with bores
54 and 56 in bottom housing 34. Bore 56 extends vertically fxom
horizontal ~ore 54 to provide communication with the bore of rotameter
flow tube 20 at its bottom end.
Top housin~ 33 is formed with a bore 57 for receiving sealing
spindle 59. Spindle 59 is threaded at the upper portion 40 of bore 60,
which extends through spindle 59. Upper portion 40 threadably engages
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screw member 37. Member 37 is aclapted to be rotated bv
external means and preferably has hexa~onal driving means
38. Retaining washer 43 supports screw member 37~ Se~ling
means 61, preferably an O-rin~, is retained between housin~
33 and member 37 to prevent any leakin~ of the flowin~
fluid.
Seal spindle 59 is provided with a flat portion
41 extendin~ alonq a substantial portion of its length.
Flat 41 is contacted by the end of fluid outlet fitting 35.
The imprin~ement of fitting 35 on flat 41 prevents spindle
59 from rotating when screw member 37 is rotated. The
rotational motion of screw mem~er 37 is translated into the
axial movement of spindle 59. ~ealin~ means 42 establishes
a seal hetween the lower portion of spindle 59 and housin~
33.
- Insert unit ln is adaptecl to be inserted in frame-
work 30 within the space clefined hv end housings 33 and 34
and side members 31 and 32. Insert unit 10 is comprised of
side support panels 12 and 13 and end panels 14 and 15.
End panels 14 and 15 are joined to panels 12 and 13 at
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-` the ends thereof and support meter tube 20 at a central
location hy means of a hole 21 which receives tube 20
recessed portion 22 is formed in each encl panel 14 and 15
to receive sealing washers 45 and 46 respectively.
Recesses portion 22 also creates a resilient lip surrounclin~
hole 21 in each of the en~ panels 14 and 15 for facile
insertion of tube 20 into end panel 14, Hols 21 is fixed
to provicle a friction fit with tuhe 20, The resilient lip
functions to ~rip tube 20 at a fixed position so that tube
20 will not slip from hole 21 and also to centrally locate
tube 20 within in~ert unit 10~ ~ide panels 12 and 13 are
formed with ~rooves 63 at the forward edges thereof
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to facilitate removal of insert unit 10 from framework 30.
A clear, front-viewing panel is interposed between side panels 12
and 13. Slots 18 are found in sides 12 and 13 to receive panel 16. In a
preferred e~bodiment panel 16 is convex lens to provide a magnifying effect
to assist in reading of the indicia on tube 20.
Back panel 17 is interposed between side panels 12 and 13 and is
retained within slots 19. Back panel 17 is formed from material
substantially thinner than side panels 12 and 13, front panel 16 and end
panels 14 and 15, and is adapted to release from slots 19 under a
differential pressure which is on the order of several inches of water.
Consequently, if pressure in the fluid system causes tube 20 to explode, the
excess pressure in unit 10 will cause panel 17 to move outwardly and release
the then present forces and glass from the back of the rotameter. The
explosion created by any tuke failure thus is controlled in a particular
direction which can be chosen to minimize the danger of injury. The
particular described ~mbodiment is advantageous in the process industries
where rotameters are conventionally panel mounted. In those installations,
it is apparent that the full force of the explosion will be directed in back
of the panel, thus minimizing the chance of injury to cperators and other
personnel who may be observing in front of the mounting panel.
When insert unit 10 is located within framework 30, tube 20
automatically is centered over bore 56 in housing 34 and under sealing
spindle 59 and bore 60. Sealing washers 45 and 46 provide a seal between
tube 20 and framework 30. In a preferred emkodiment sealing washers 45 and
46 are formed with an L,shaped transverse cross section so that they ;
function both to seal the tube and hold it in insert 10.
It is preferable to dimension insert 10 so that it fits flush
within Eramework 30. Tube 20 then is centered appropriately in fr~mework 30
in a si~le operation. Then sealing spindle 50 is moved downwardly by
rotating screw member 37 to force sealing washers 45 and 46 against
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the top and bottom of tube 20, respectively. As stated hereinbefore,
flat 41 prevents spindle 59 from rotating and tube 20 renains in its
insertion position. Accordln~ly~ it is no longer necessary to estimate
an initial insertion position for the tube 20 wnich hopefully ~ould end
with front-facing indicia when the seal was completed.
It is apparent that one insert unit can be used with a
multitude of tubes with different inside diameters. Also, different
shapes for the insert unit could be provided depending on the shape of
the frame;wor~c into which it is to be inse~ed.
In another embodi~ent of the invention, insert 10 can be
adapted to form a sealed structure about tube 20. Insert 10 can be
filled with dry nitrogen or other inert gas to prevent condensation and/or
frost from forming on the surface of tube 20, which might impair or even
prevent accurate flow readin~s. Also, it is desired to form bottom
panel 15 with a small groove in front of the front panel. That grcove
facilltates rem~val of insert 10 when operations have been concluded
either by means of a finger or thumb nail or an-appropriately shaped
instrument, which can be inserted into the groove and pulled outwardly.
The invention has been illustrated with reference to the
drawings but it will be-apparent to those skilled in the art that
modifications can be made without departing from the splrit or scope of
this lnventlon.
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