Abstrict This invention relates to a method for seating a pitot tube type
flow meter against the remote wall of the pipe in which it is being
installed and subsequently sealing same within the tubular fitting
through which it enters the pipe, such method comprising using a
movable abutment to push compressible packing contained within an
annular space provided between the outside of the pitot tube and
the inside of its tubular fitting against a fixed abutment on the
pitot tube thereby forcing the latter inward until it bottoms on
the remote pipe wall and thereafter continuing to advance the movable
abutment to narrow the gap between it and the fixed abutment so
as to compress the packing between the two until it expands to fill
the annular space and form a fluid-tight seal around the pitot tube.
The invention also encompasses the novel apparatus for carrying
out the above-described method.
Claims What is claimed is:
1. An apparatus for use in both seating a remote end of a pilot
tube type flow meter probe against the opposite wall of a pipe in
which it is being installed and also for sealing same within a tubular
guideway that borders a side-opening probe-entry port in the pipe
as it encircles a similarly-shaped section of the probe body in
spaced relation thereto to form a seal-receiving annulus therebetween,
the pipe being subject to size variations which can cause the diameter
of the pipe to be oversized or undersized with respect to a design
standard, which comprises: control means for ensuring that said
probe remote end is seated against the opposite wall of the pipe
before the probe is sealed within the tubular guideway, said control
means including a fixed abutment movable with the prove body and
sized for insertion into the seal-receiving annulus said fixed abutment
being located on said probe body to define a gap between the sidewall
of the pipe adjacent to said probe-entry port and said fixed abutment,
said fixed abutment being positioned on said probe body with respect
to the remote end of the probe so that the size of the gap exceeds
a maximum oversize variation in the diameter of the pipe and so
that no stop-forming obstruction is located between said fixed abutment
and the pipe sidewall adjacent to said probe entry port so that
when the probe remote end is seated against the opposite wall of
the pipe and after sealing there is no compressive force applied
to said fixed abutment by the pipe sidewall adjacent to said probe-entry
port; sealing means for sealing the probe body within the tubular
guideway comprising compressible packing material movable along
said body within the seal-receiving annulus into abutting relation
with the fixed abutment on the side of said fixed abutment opposite
to the remote probe end, said compressible packing material being
adapted to expand into contact with the guideway when compressed
and being movable axially of the guideway before being compressed;
and, a movable abutment movably positioned on the probe body at
a location spaced from said fixed abutment and being movable into
position to push the packing material against the fixed abutment
and force the fixed abutment along with the probe forwardly toward
the opposite pipe wall until the remote end of the probe seats against
the opposite pipe wall, and said movable abutment upon further movement
toward said probe remote end being operative to narrow the space
between it and the fixed abutment thereby compressing and expanding
the packing material into contact with the guideway to form a continuous
annular fluid tight seal around the probe body.
2. The apparatus as set forth in claim 1 in which: the movable
abutment includes actuating means detachably connectable to the
tubular guideway for axial movement relative thereto along the probe
body, said movable abutment and actuating means when the latter
is thus connected cooperating to define a stop effective to engage
the packing and limit the movement of the probe in a direction to
withdraw same from the pipe.
3. The apparatus as set forth in claim 2 in which: the actuating
means comprises a centrally-apertured cup threadedly attachable
to the tubular guide member for rotational as well as axial movement
relative thereto and to the probe and packing.
4. The apparatus as set forth in claim 3 in which: the stack of
compressible rings is bordered on both ends by substantially non-compressible
rings defining spacers between said stack and the fixed and movable
abutments.
5. The apparatus as set forth in claim 1 in which: the packing
material comprises a stack of at least two compressible rings.
6. The apparatus as set forth in claim 1 in which: the fixed abutment
comprises a continuous annular rib encircling the probe body.
7. The apparatus as set forth in claim 1 in which: the movable
abutment includes a ring at least partially encircling the probe
body sized for insertion into the packing-receiving annulus.
8. The apparatus as set forth in claim 1 in which: the movable
abutment comprises a subassembly including a ring encircling the
probe body for axial movement therealong in abutting relation to
the packing and an actuating means detachably connectable to the
tubular guideway for axial movement relative thereto along the pipe
in abutting relation to said ring.
9. The apparatus as set forth in claim 8 in which: the subassembly
includes at least one spring-type washer interposed between the
actuating means and the movable abutment encircling the probe body
within the packing-receiving annulus.
10. The apparatus as set forth in claim 8 in which: the actuating
means of the subassembly comprises a centrally-apertured cup sized
to slide along the probe body into abutting engagement with the
movable abutment, said cup being threadedly connectable to the tubular
guideway for rotational and axial movement relative thereto and
to said abutments, packing material and probe body.
11. The method for seating the remote end of a pitot tube type
flow meter probe against the opposite wall of a pipe into which
it is being installed and thereafter sealing and holding same in
fixed axial position within a tubular guideway through which it
enters a side-opening port in said pipe which comprises the steps
of: mounting compressible packing material on the probe and spacing
that compressible packing material from the tubular guideway to
define an annular space between the compressible packing material
and the tubular guideway with the packing material being axially
movable in that space with respect to that guideway; using a movable
abutment to push against the compressible packing material and force
that compressible packing material against a fixed abutment carried
by said probe body thereby forcing the latter inward until it bottoms-out
on the opposite pipe wall and thereafter continuing to advance the
movable abutment to narrow the gap between it and the fixed abutment
so as to compress the packing between the two until it expands into
contact with the tubular guideway to fill the annular space and
form a fluid-tight seal around said probe body while simultaneously
holding same in bottomed-out position within the pipe.
12. The method as set forth in claim 11 which includes the step
of: interconnecting the movable abutment and tubular guideway for
relative axial movement such that they cooperate when so connected
to block and prevent withdrawal of the probe body from the pipe.
13. An apparatus for use in both seating a remote end of a pitot
tube type flow meter probe against the opposite wall of a pipe in
which it is being installed and also for sealing same within a tubular
guideway that borders a side-opening probe-entry port in the pipe
as it encircles a similarly-shaped section of the probe body in
spaced relation thereto to form a seal-receiving annulus therebetween,
the pipe being subject to size variations which can cause the diameter
of the pipe to be oversized or undersized with respect to a design
standard, which comprises: control means for ensuring that said
probe remote end is seated against the opposite wall of the pipe
before the probe is sealed within the tubular guideway, said control
means including a fixed abutment sized for insertion into the seal-receiving
annulus and mounted on the probe body for movement therewith, said
fixed abutment being located on said probe body to define a gap
between the sidewall of the pipe adjacent to said probe-entry port
and said tixed abutment, said fixed abutment being positioned on
said probe body with respect to the remote end of the probe so that
the size of the gap exceeds a maximum oversize variation in the
diameter of the pipe and so that no stop-forming obstruction is
located between said fixed abutment and the pipe sidwall adjacent
to said probe entry port so that when the probe remote end is seated
against the opposite wall of the pipe and after sealing there is
no compressive force applied to said fixed abutment by the pipe
sidewall adjacent to said probe-entry port; sealing means for sealing
the probe body within the tubular guideway comprising compressible
packing material movable along said probe body within the seal-receiving
annulus into abutting relation against the fixed abutment; and,
a movable abutment movably located on said probe body to be spaced
from said fixed abutment and adapted to be moved into a position
to push the packing material against the fixed abutment and force
the fixed abutment along with the probe toward the opposite wall
of the pipe until the remote end of the probe seats against the
opposite pipe wall, a movable abutment actuating means movably attached
to the tubular guideway, said movable abutment being sized so that
said movable abutment, said movable abutment actuating means, and
said tubular guideway remain operatively associated for oversized
and undersized pipes, said movable abutment having one surface located
to be engaged by said movable abutment actuating means and another
surface located to engage said packing material to move said packing
material when said actuating means moves said movable abutment via
said movable abutment one surface, said movable abutment upon further
forward movement toward said probe remote end after said remote
end has seated against the opposite wall of the pipe being operative
to narrow the space between it and the fixed abutment in a manner
which compresses and expands the packing material into engagement
with said tubular guideway to form a continuous anuular fluid-tight
seal around the probe body.
14. An apparatus for use in both seating the remote end of a pitot
tube type flow meter probe against the opposite wall of a pipe in
which it is being installed and also for sealing same wtihin a tubular
guideway that borders a side-opening probe-entry port in the probe
body in spaced relation thereto to form a seal-receiving annulus
therebetween with the probe having one end which is adapted to extend
out of the pipe when the probe is in position on the pipe, the pipe
being subject to size variations which can cause the diameter of
the pipe to be oversized or undersized with respect to a design
standard, the apparatus comprising: control means for ensuring that
said probe remote end is seated against the opposite wall of the
pipe before the probe is sealed within the tubular guideway, said
control means including a fixed abutment mounted on the probe body
for movement therewith, said fixed abutment being located on said
probe body to define a gap between the sidewall of the pipe adjacent
to said probe-entry port and said fixed abutment, said fixed abutment
being positioned on said probe body with respect to the remote end
of the prove so that the size of the gap exceeds a maximum oversize
variation in the diameter of the pipe and so that no stop-forming
obstruction is located between said fixed abutment and the pipe
sidewall adjacent to said probe entry port so that when the probe
remote end is seated against the opposite wall of the pipe and after
sealing there is no compressive force applied to said fixed abutment
by the pipe sidewall adjacent to said probe-entry port; sealing
means for sealing the probe body within the tubular guideway, said
sealing means including compressible packing material positioned
on said probe body and adapted to expand radially outward from said
probe body when compressed axially of said probe body, said packing
material being mounted on said probe body and sized to move with
said probe body within said seal-receiving annulus into abutting
contact with the fixed abutment which is located on the probe so
the compressible packing material is located between the one end
of the probe and the fixed abutment, and a movable abutment movably
mounted on said probe body at a location spaced from said fixed
abutment and movable along the probe body into position to push
the compressible packing material against the fixed abutment and
force the packing material along with the probe forwardly toward
the opposite pipe wall until the remote end of said probe seats
against the opposite pipe wall, and said movable abutment upon further
movement toward the probe remote end being operative to narrow the
space between it and the fixed abutment for axially compressing
and radially expanding the compresssible packing material to force
that compressible packing material against the tubular guideway
to form a continuous annular fluid-tight seal around the probe body
after the probe has seated against the opposite pipe wall, said
compressible packing material being sized and arranged relative
to said seal-receiving annulus so that said fluid-tight seal is
formed only after said probe has seated against the opposite pipe
wall.
15. The method for seating the remote end of a pitot tube type
flow meter probe against the opposite wall of a pipe into which
it is being installed and thereafter sealing and holding same in
fixed axial position within a tubular guideway through which it
enters a side-opening port in said pipe which comprises the steps
of: positioning the compressible packing material on the probe to
be located within an annular space provided therefor between the
outside of the probe and the inside of the tubular guideway; then
using movable abutment to push against the compressible packing
material and to force that packing material against a fixed abutment
mounted on said probe to force said probe toward the opposite pipe
wall until it bottoms-out on that opposite pipe wall, and therafter
continuing to advance the movable abutment to narrow the gap between
it and the fixed abutment so as to compress the packing between
the two until it expands to fill the annular space and into contact
with the guideweay; forming a fluid-tight seal around said probe
only after the probe has bottomed-out against the opposite pipe
wall; and simultaneously holding said probe in the bottomed-out
position against the opposite pipe wall while forming said fluid-tight
seal.
Description In copending U.S. patent application Ser. No. 769431 filed Aug.
26 1985 now U.S. Pat. No. 4645242 issued Feb. 24 1987 owned
by the assignee of the present application, a high-pressure blowout-proof
mounting for a pitot tube type flow measurement device is disclosed
wherein a fixed abutment encircling the body of the probe and movable
therewith is positioned to be engaged by an inturned stop-forming
flange formed integral with a cap nut that screws onto a sealable
tubular compression fitting welded or otherwise attached to the
pipe at the opening in its sidewall where the probe enters same.
As illustrated, this compression fitting has two threadedly interconnected
parts which cooperate with one another when tightly assembled to
engage, grip and form an annular fluid-tight seal around the cylindrical
probe body effective to securely maintain it in its proper position
extending diametrically across the pipe in which the flow is to
be measured. The cap nut and its inturned flange-forming stop only
become operative to engage the annular abutment carried by the probe
body to prevent the latter from being blown out of the pipe, when
purposely or through an oversight, the compression fitting that
holds same in place, is loose. This may be done intentionally when
the pipe is pressurized and the probe is to be retracted and withdrawn
from the flow but not removed from its mounting.
From a functional standpoint, the preferred placement of pitot
tube type flow measurement instruments is extending diametrically
across the pipe with the remote end in engagement with the opposite
pipe wall. It is only in this position that the precisely-located
upstream and downstream-facing pressure-sensing ports lie where
they should be to provide the differential pressure measurement
information necessary to produce an accurate reading. It has also
been discovered that having the probe body "bottomed-out"
so to speak on the opposite pipe wall is very important from an
operational standpoint, especially in large diameter pipes containing
fast-moving fairly viscous fluids. If the remote end of the probe
is left to swing free, it oftentimes begins to vibrate and sometimes
even breaks off, either of which is most undesirable.
In those blowout-proof installations where the probe is provided
with some kind of fixed abutment designed to engage a stop in the
event of a loose connection, this same fixed abutment may serve
a dual function of a stop positioned and adapted, either intentionally
or inadvertently, to engage the near pipe wall adjacent the probe-receiving
opening therein or some other obstruction projecting, perhaps, from
the mounting hardware thus limiting the degree of probe penetration
into the pipe. When this happens, there is no assurance whatsoever
that the remote end of the probe will bottom-out against the remote
pipe wall before the abutment engages its near wall. As a matter
of fact, the allowable dimensional variations in the i.d. of pipe
being what they are, it is almost a sure bet that if an abutment
on the probe body is selectively positioned to engage and stop against
the near pipe wall at the same time the remote end of the probe
strikes its opposite wall based upon the assumption that the pipe
has an accurate i.d. and wall thickness, that in a good percentage
of the installations the probe will not reach to the opposite wall
at all but terminate well short thereof. Alternatively, while not
as serious a problem in that the probe can bottom-out properly,
some provision must be made for accommodating an undersized pipe
in the sense of being able to maintain a secure connection as well
as a fluid-tight annular seal.
Even in those installations in which the probe body is free of
any abutment that could possibly interfere with its bottoming-out
on the opposite pipe wall, a very real chance still exists that
it will be installed improperly and not do so. To begin with, positioning
of the probe, of necessity is done "blind" in that the
installer cannot see where the remote end of the probe is relative
to the opposite pipe wall. Moreover, realizing that the probe is
a delicate precision measuring instrument, he or she is reluctant
to bang it hard into the opposite wall for fear of damaging the
unit. Even though properly seated, there is no assurance that the
probe will not back off a little while the compression fitting or
other seal is being made.
A considerable improvement in high pressure mountings for pitot
tube type flow meters would result if one could insure that its
remote end was bottomed-out against the remote pipe wall and remained
so while the sealed connection was being made. If, incidentally,
this same construction could be relied upon to hold the probe securely
in place within the pipe, produce a fluid-tight seal therearound
as well as provide blowout protection in the rare event of a loose
connection, all the better.
The closest prior art known to applicant is contained in a single
patent, namely, the early U.S. Pat. No. 1250238 to Spitzglass
where in FIGS. 1 and 6 he illustrates two different types of packings
18 designed to form a fluid-tight annular seal between what he denominates
his sleeve 16 and his plug 9. It is important to note, however,
that as stated in column 1 of page 2 of the specification beginning
down at line 40 that ". . . collar 7 is secured to the plug
member 9 to hold it and the sleeve together." As stated the
function of collar 7 must be one of holding the sleeve 16 and the
plug 9 together to prevent relative axial movement therebetween
although it would appear that they could, perhaps, rotate relative
to one another. This being the case, while the remote end of the
probe is shown seated against the opposite pipe (tube 8) wall, if
this were not the case, no amount of relative movement of so-called
"packing gland 17" against "packing 18" would
be effective to seat the remote end of the probe since the connection
between the plug 9 and sleeve 16 provided by collar 7 would prevent
it. Apparently, seating of the probe against the opposite pipe wall
is achieved by screwing the sleeve 16 deeper into tube 8 by means
of unnumbered threaded opening that receives the assembly although
the extent to which this can be done is apparently quite limited
due to the tapered thread on the sleeve which can only enter the
tube so far.
The description of FIG. 6 makes no mention of the packing subassembly
but it only appears to differ in the cross section of the packing
18 and the fact that there is no annular shoulder inside the sleeve
16 for the packing gland 17 to abut against. As such, it is difficult
to ascertain from the drawings whether there is anything in the
way of a stop or shoulder analogous to what is seen in FIG. 1 to
prevent the packing gland from moving axially inward to further
compress the packing. Nevertheless, if as stated the collar holds
the sleeve and the plug together, then using the packing gland to
compress the packing cannot have the effect of moving the plug and
probe axially inward relative to the sleeve to seat the probe against
the remote wall of the tube.
Even if one were to assume that Spitzglass' sleeve and plug were
not fastened together as he says by collar 7 and, therefore, presumably
could not move axially relative to one another and, in addition,
assume that the thin unnumbered washer-like member on the opposite
side of the collar from the packing 18 was compressible, it is perfectly
obvious that the maximum degree of axial adjustment to insure that
the probe seats securely against the opposite tube wall would be
a tiny fraction of an inch which is not anywhere near adequate to
accommodate the dimensional variations likely to exist in a tube
or a pipe having an internal diameter literally hundreds of times
greater than the overall thickness of the washer shown. Such assumptions
also presume that Spitzglass even recognized the problem which it
is apparent he did not do. Instead, he was merely applying conventional
packing gland technology to seal the probe in its mounting hardware.
Applicant has now discovered a virtually foolproof method and apparatus
for insuring that the probe body is securely seated against the
opposite pipe wall and, while doing so, he forms a fluid-tight seal
around the probe and prevents it from blowing out under pressure
should the seal fail or not have been made tight in the first place.
This desirable end is accomplished by the novel expedient of first
using the packing and a movable abutment movable thereagainst to
push against a fixed abutment on the probe body for the purpose
of driving the remote end thereof against the opposite pipe wall.
Thereafter, once the probe has bottomed-out and no further inward
movement of it or the fixed abutment carried thereby relative to
the pipe is possible, the movable abutment is moved farther in to
narrow the gap left between it and the fixed abutment so as to squeeze
the packing therebetween and cause the latter to expand into fluid-tight
sealed relation to the probe by compressing it into the annular
space left between the probe and the tubular housing therefor. To
accomplish the above, a sufficient gap must be left between the
fixed abutment and any fixed obstruction between it and the remote
end of the probe to accommodate any gap that might be encountered
between the probe end and the adjacent pipe wall resulting from
dimensional irregularities, deformation of the pipe or other anomalies.
If the element of the assembly responsible for moving the movable
abutment relative to the fixed one is also adjustably attached for
relative axial movement to the tubular sleeve welded to the pipe
that houses and guides the probe body for insertion into the opening
therefor in said pipe wall, such element will also function when
thus connected to define a stop effective to prevent the probe from
blowing out under pressure should the seal fail or come loose or
be loosened.
It is therefore, the principal object of the present invention
to provide a method and apparatus for insuring that a pitot tube
type flow measuring instrument has its probe body bottomed-out against
the remote wall of the pipe in which it is located preparatory to
forming the mechanical connection between the unit and the tubular
sleeve by means of which it is attached to the pipe.
A second objective is the provision of a method and apparatus of
the type aforementioned which also functions to seal the probe body
within its mounting once the probe is in the proper position and
the connector subassembly continues to be actuated.
Another object of the invention herein disclosed and claimed is
to provide, in addition to the aforementioned objectives, a blowout
proof mounting that is effective to prevent the probe from coming
out of its mounting even though the seal is loose or loosened.
Still another object of the within-described invention is to provide
a combination pitot tube mounting assembly that seats the probe
body in proper position against the remote pipe wall, seals the
body within the mounting and prevents the latter from being blown
out should the seal fail or be loosened.
An additional objective is to provide a sequential mounting method
for pitot tube type flow measurement probes and the like which first
insures that the probe body is properly positioned and holds it
there before forming a fluid-tight seal therearound.
Further object are to provide a mounting assembly and method of
using same of the character described which are simple to use, inexpensive,
effective, versatile and require no special skills to operate.
Other objects will be in part apparent and in part pointed out
specifically hereinafter in connection with the description of the
drawings that follows, and in which:
FIG. 1 is a diametrical section, portions of which have been broken
away to conserve space, showing the pitot tube and its mounting
assembly in relaxed position preparatory to seating the remote end
of the probe body against the opposite pipe wall;
FIG. 2 is another diametrical section similar to FIG. 1 and to
the same scale but showing the probe body in seated position and
the movable abutment about to continue its inward excursion to compress
and expand the packing into fluid-tight sealed relation against
the fixed abutment carried by the probe;
FIG. 3 is still another diametrical section similar to FIGS. 1
and 2 but differing therefrom in that it reveals the probe body
seated, the annular fluid-tight seal formed therearound and the
blowout prevention subassembly in place;
FIG. 4 is a fragmentary diametrical section to the same scale as
the preceding figures showing a modified version of the assembly
wherein a pair of spring washers are interposed between the movable
abutment and the packing; and,
FIG. 5 is another fragmentary diametrical section showing a still
further modification in which the cap nut of the preceding embodiments
used to move the movable abutment is replaced by a simple flat plate
bolted to the tubular guide sleeve of a conventional flanged side-opening
port in the pipe wall.
Referring next to the drawings for a detailed description of the
present invention and, initially, to FIGS. 1 2 and 3 for this purpose,
reference numeral 10 has been selected to broadly designate the
pitot tube type flow measurement probe having in the particular
form illustrated a slightly oversize cylindrical body section 12
to which is permanently attached a fixed abutment 14 the latter
taking the form of an annular rib welded to the probe body in the
particular form shown. A large diameter pipe 16 having a probe-receiving
opening 18 therein loosely receives the portion 20 of the probe
body that will lie within the flow and which contains the pressure-sensing
ports 22.
A mounting assembly that has been indicated in a general way by
reference numeral 24 performs several functions including that of
guiding the portion 20 of the probe body diametrically across the
pipe at right angles to its axis, detachably fastening the unit
to the pipe, forming a fluid-tight seal therearound and, incidentally,
providing same with blowout protection in case the seal fails or
is loosened. In FIGS. 1 through 4 inclusive, it can be seen that
in the particular form shown the aforementioned assembly includes
among other things a tubular guide sleeve 26 which is welded or
otherwise attached to the outside of the pipe 16 and which loosely
receives the probe body so as to leave an annular space 28 therebetween
for the compressible packing 30 along with the relatively non-compressible
spacers 32 shown on both the top and bottom thereof in the particular
embodiment illustrated. These spacers 32 are not required in the
assembly and, therefore, may be left out; however, their inclusion
is sometimes recommended to insure a proper fluid-tight annular
seal. The axis of this guide sleeve should be oriented such that
it intersects the axis of the pipe at right angles thus insuring
that the probe body axis does likewise. Obviously, the sleeve should
be centered as close as is practicable over probe-receiving opening
18. Sleeve 26 is shown externally threaded at 34 to receive an internally-threaded
and centrally-apertured cup that defines a cap nut 36 the central
opening 38 in the top thereof of which is sized to loosely pass
the probe body 12 as shown. This cap nut is the actuator of the
reference numeral 24 assemblies that functions to move the movable
abutment 40 up and down relative to the probe body 12 within the
annular space 28 left between it and its housing or sleeve 26 for
the purposes which will be explained in detail presently. As revealed
in FIGS. 1-4 the cap nut 36 and movable abutment 40 are separate
parts constituting a movable subassembly; however, they may be formed
integral with one another especially if a washer-like spacer 32
which can effectively resist the resulting relative rotational movement
of the movable abutment is interposed between the latter and the
rather more frail and easily damaged packing 30.
As illustrated in FIGS. 1 2 and 3 the movable abutment comprises
a sleeve slidable along the probe body. In the modified assembly
24M of FIG. 4 on the other hand, the movable abutment includes
not only sleeve 40 but one or more wave or other type of spring
washers 42 interposed between it and the inturned flange 44 bordering
the opening 38 in the cap nut. The packing 30 is shown as comprising
a stacked series of rings made out of any one of a number of types
of conventional compressible packing materials capable of expanding
within the annular space 28 between the probe body and the guide
sleeve 26 housing same to form a fluid-tight annular seal therearound.
This packing together with spacers 32 are, of course, confined within
annulus 28 between the fixed abutment 14 on the probe body and the
movable abutment 40 thereabove.
Next, with particular reference to FIG. 1 it can be seen that in
the particular form shown, the maximum outside diameter of the fixed
abutment 14 is such that it will not pass through the probe-receiving
opening 18 in the near pipe wall nor would it likely pass any other
obstruction therebetween such as, for example, a projection on sleeve
26 projecting into annular space 28 which could, conceivably form
a part of the mounting assembly 24. Thus, the portion of the near
wall of the pipe 16 bordering opening 18 or some other obstruction
could, conceivably, constitute a stop effective to prevent the remote
end 46 of the probe body from reaching and bottoming-out on the
opposite pipe wall 48. Accordingly, knowing the permissible dimensional
variations in a given size pipe fabricated from various materials
which, by the way, can be substantial, it is important that the
gap 50 left between the opposed surfaces of the pipe 16 or any other
obstruction and the fixed abutment 14 at least equal, and preferably
substantially exceed, the maximum oversize variation in the diameter
of the pipe into which the probe will be introduced. When thus dimensioned,
one is assured that the remote end 46 of the probe can seat securely
against the opposite pipe wall 48 before the fixed abutment 14 can
contact any stop-forming obstruction on the near wall of the pipe
or sleeve 26.
As shown in FIG. 2 the gap 50 is sized so that when the probe
remote end is seated against the opposite wall of the pipe 16 and
the probe is sealed in the tubular guideway, there is no contact
between the fixed abutment 14 and the pipe wall adjacent to that
fixed abutment. Hence, there is no compressive force applied to
that fixed abutment by that pipe wall after the sealing is completed.
While on the subject of dimensional anomalies in the pipe, it is,
of course, as much of a possibility that the pipe is undersized
as oversized. If undersized, there is no problem of the probe body
seating against the remote pipe wall; however, one must insure that
cap nut 36 is securely fastened to sleeve 26. Accordingly, the length
of movable abutment 40 can be selected to accommodate any particular
oversize or undersize situation.
Starting with FIG. 1 and continuing on to FIGS. 2 and 3 the method
of mounting and sealing the probe to insure its being bottomed-out
against the opposite pipe wall will now be described. Initially,
as seen in FIG. 1 all the elements of the mounting assembly are
loose and the remote end 46 of the probe body lies spaced apart
from the opposite pipe wall 48. However, it is significant to note
that the gap 52 left between the remote end 46 of the probe and
the opposite pipe wall 48 is considerably smaller than the gap 50
left between the opposed surfaces of the near wall of the pipe bordering
opening 18 therein or any other obstruction and the fixed abutment
14. Next, looking at FIG. 2 it can be seen that the cap nut 36
has been screwed down part way onto the threaded neck 34 of guide
sleeve 26 so as to push the movable abutment 40 down atop the stack
of packing rings 30 and spacers 32 which, in turn, press against
the fixed abutment 14 to force the probe inward until its remote
end 46 seats securely against the opposite pipe wall 48 all without
the fixed abutment striking any abutment ahead of it. Significantly,
the packing rings 30 will have been compressed very little since
both the probe body 12 and its fixed abutment 14 can yield and move
with them and the assembly thereabove as the portion 20 of the probe
10 moves on into the pipe. Once the remote end 46 of the probe body
12 seats against the opposite pipe wall 48 however, the situation
changes and the sequence shown in FIG. 3 begins. Obviously, there
can be no more essentially coordinated movement of the fixed and
movable abutments, the probe body, the packing, the spacers and
the cap nut as was the case up until the probe end 46 reached the
opposite pipe wall since the probe and its fixed abutment have stopped
all further movement relative to the pipe. On the other hand, the
cap nut 36 can continue to move inward toward the pipe as it is
screwed farther down onto the threaded neck 34 of guide sleeve 26.
As the movable abutment and the cap nut move down relative to the
fixed abutment as seen in FIG. 3 the packing 30 is compressed therebetween
and expanded to fill the progressively smaller annular volume defined
between these abutments and the opposed surfaces of the guide sleeve
and the probe body inside thereof until an annular fluid-tight seal
is formed therebetween. The tightly compressed packing, in addition
to forming the annular seal, also securely fastens the probe in
bottomed-out position within the pipe. It is important to note that
the seal cannot be formed nor can the probe be held in a fixed position
relative to the pipe until the probe is, in fact, bottomed-out as
aforementioned because sequentially the probe must reach the end
of its axial travel before the packing can be compressed. Also,
the probe cannot back out of the pipe until the seal comes loose
or is intentionally loosened. If, perchance, the seal comes loose
or is loosened on purpose, the inturned flange 44 atop the cap nut
36 that engages the movable abutment 40 when screwed inward so as
to fasten and seal the probe in place within its mounting assembly
will also function in any of its various threadedly-connected positions
to block the removal of probe and thus prevent a blowout. No novelty
per se is predicated upon this feature since Spitzglass' collar
7 holding his sleeve 16 and plug 9 together will do the same thing.
Even if his collar were not connected in some way to the sleeve,
it would eventually come into contact with the inner end of packing
gland 17 thus preventing a blowout provided that the packing gland
was threadedly connected to the sleeve as he shows it.
Turning the attention briefly to FIG. 4 a slightly modified form
of the mounting assembly 24M has been shown in which one or more
wave or other form of spring-type washers 42 are interposed between
the inturned flange 44 on the cap nut 36 and the top of the movable
abutment 40. These washers are added for the purpose of maintaining
the packing 28 under a more or less constant and yieldable, but
nonetheless predictable, compression load which is somewhat more
difficult to achieve with the cap nut itself. In addition, these
washers function to take up any space caused by expansion of the
pipe or relaxation of the packing so as to maintain packing loading.
Nevertheless, the assembly works quite satisfactorily without them.
Finally, looking at FIG. 5 a still further modified form of the
mounting assembly 24N has been shown wherein a cylindrical guide
tube 26M is welded in place atop a centrally-apertured flange 54T
that mates with a like flange 54B which, in the particular form
shown, is formed integral with a collar 56 that defines a side-opening
entryway 18M into the pipe 16M, the latter being of more or less
conventional design. In accordance with standard practice, the flanges
are bolted together using bolts 58 with a gasket 60 in between the
flanges.
Replacing the cap nut 36 of FIGS. 1-4 is a cap plate 62 corresponding
functionally to the inturned flange 44 of the latter but differing
therefrom in that it contains a series of apertures 64 which align
with corresponding internally threaded screw-receiving sockets 66
in the top of the sleeve 26M through which and into which the cap
screws 68 thread. Thus, the cap plate, cap screws and guide tube
cooperate in the same way as elements 26 and 36 of the previously-described
embodiments to provide an actuator subassembly operative to push
the movable abutment 40 down against the stack of packing rings
30 and spacers 32. The subassembly that comprises the aforementioned
movable abutment 40 packing rings 30 and fixed abutment 14 with
or without the spacers 32 remains the same as that of the previously-described
embodiments and functions in the same way as the cap screws are
screwed deeper into their respective sockets to draw down the cap
plate. Some further modification of the flanged embodiment of FIG.
5 would, obviously, be required to accommodate the wave or other
form of spring-type washers 42 without having to drill them to accept
the cap screws. There remain, of course, other mounting assemblies,
conventional and otherwise, that will accommodate the movable abutment,
the packing and the annulus for the latter to expand into while
forming the seal that will be the full functional equivalent of
the instant invention, yet which have not been illustrated.
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