Note: Descriptions are shown in the official language in which they were submitted.
3~D
Il SAMPLER ~
Thls invention relate~ to a 3ampler for the extractlon Or
fluid sample~ in rlowlng or static ~tate.
There 13 a ereat need to 3ample liquid, ror examp~e, crude
oil undzr sub~tantially isokinetic condltlons. Many devices exl~ts
but they do not take representat~ve ~amples becau3e they do not
operate ln accordance with ~okinetic principle3. Somel for example,
use c~mplex bypass loop~ with mot~r drlven circulating pumps. Some
lack racilities ror po~sible eJection Or the sample and have a loneer
and complex rlow path to the sample receptacles. Others are not bi-
directional and others are e~tremely complex unit~ with ~any component
parts. Some have nD racilities ror chan~ing the quantity of sample~.
For 3ampling under non-isokinetic condition~, samplers are
known which are Or relati~ely simple construction~ One such sampler
employs a block Or rubbery material with a cavity therein in which a
liquid sample is trapped by an advancing piston and then expelled
through a passage way ~n the piston as the piston s~uashes the cavity
and the rubbery block ~lat~ However, with sufriciently prolonged u~e,
the rubbery material deteriDrates and eventually rails and, ln any
case, is generally unsuitable for high temperature use which can for
example be encountered when sampling North Sea oil. In another
samyler, a closed-ended cylinder is used in place Or the rubbery block
but the hydraulic shock-waves produced when the piston enters the open
end Or the cylinder, ]particularly at high ~ampling rates9 can rupture
the internal seals and even cau~e severe internal damage.
., ~
33~
-- 2 --
Another known ~a~pline device, which i8 not s~bJect to the
dl~advantage Ju~t mentloned, operates wlth rotary action to trap a
llquid sa~ple in a cylindrical sample cup by rotatlng a cylindrlcal
sleeve intD a ~ir~t position, and then causing a pi3ton ln the ~ample
chamber to e~ect the trapped ~ample through a pa~sageway leading rrom
the sample chamber. This sampler, ho~ever, surfers from a number of
drawbacks9 viz., constructional complexity, large bearing 3urraces in
~liding contact leading to increased wear and ri~k Or ~amming caused
by dirt, practical sealing difficultieq, and lim~tation on the sampling
rate caused by the piston displacement speed during sample expulsion
being governed by the line pressure Or the pipe line or similar into
which the ~ampler iq fitted.
The present inYention i~ concerned with proYiding a
sampling device which is of ~imple con~truction, has a long and
trouble ~ree ~er~ice lifeJ is ~ultable for high temperature use
and can be ~dapted for isokinetic sampling.
In ~ummary, the invention provide~ a fluid sampler comprising
a casing having two ports in the wall thereof 90 that the casing can be
arranged in com~un~cation with a pipeline. One Or the ports enables
fluid in the pipeline to flow into the sampler and the other port
enables fluid in the sampler to rlow out Or it. A sleeve is
reciprocably ~ounted wlthin the casing and a piston is reciprocably
mounted within the sleeve.
33~
-- 3 -
Actuator means are provided which are operable for ~electlvely c~anelne
the relatlve positlons Or the caslng, sleeve and plston ~uch that in a
firAt relative po~ltlon comml~nication is provlded through a chamber
between the two port~ ~o that the chamber becomes charged with llqu1d ln
the pipeline. In a second relative po~ition a sample Or the rluid is
i301ated from khe rluid flow wlthln a space bounded by the piston, sleeve
and caslng. In a thlrd relative po3ition9 the volume Or the space i~
reduced ~or discharging rluid in the space through a passageway in
communlcation with ~pace. ThiS rluid sampler is simple ~n con~truction,
comprising essentially only three main components, viz., the casing, its
sleeve and the p~ton, these being provided with the actuator means which
can be sited at any convenient location. Becau~e none o~ the components
need3 to consist Or a rubbery material, they can-be made of materials
such as metal which are resistant to the temperature of hot liquids
and can be designed to have a very long service llre. Furthermore,
because Or the reciprocating, a3 opposed to rotary9 action of the sleeve
and pi~ton, sliding ~riction can be produced, and the likelihood of
~amminB due to inBreq~ Or dirt i~ lessened. Because both the piston
and sleeve have a reciprocating movement, the design o~ the actuator
mean9 i9 simpler than ir it were to have to reciprocate the piston
but rotationally oscillate the sleeve. ~nother advantage over the
prior art rotary action sampler where the piston is displaced under`
tbe action Or line pressure is that because the piston is reciprocated
by the action Or the actuator means, the sampler can be desiKned ror
much hi~her ~ampling rates.
~ 4 ~
Prerer~bly~ the sampler ~9 ~ dc ~en~d ~at lt c~n b~ Ir,~(:r~d
through an aperture in the plpellne and ~u~pended there ~o tha~ f~uid
can flow lnto one port and can also rlow out throueh the oth~r port.
Thls arran~ement makes the rluld sampler e~pecially ~ultable ror sampllng
oil rlowing in an oll pipeline.
In one convenient arrangement, a compresslon ~prln~, located
between the p~ston ~leeve and a shoulder, formed within the casing, and
acting at its lower end on a top part o~ the sleeve, ls provided ror bia~-
ing the sleeve toward~ a position in which the fluid sample is isolated
within said space, the spring being in it3 state Or greatest compression
when the casing, sleeve and the piston are in their first relative
positionsO This ~rrangement is compact ~nd utllises the spring force to
assi~t in rapidly di3placing the sleeve relative to the casing during
changeover of the relative positlons Or the ca~ing~ sleeve and piston
away from the first relative position.
Suitably, the body, 3ieeve and pi~ton are of circular cross-
section and the two port~ are diametrically opposite one another. Thi~
assists in providin~ simplicity of manufacture and asse~bly and linear
flow of liquid in the pipeline through the ~luid sampler.
For achieving isokinetlc flow coDditions, the shape and
design Or the ports and the chamber are chosen 90 that the ~low *hrouEh
the rluid sampler, when the casing, sleeve and piston are in their rirst
relative po3ition, is substantially isokinetic. Ihis can be achieved in
a ~luid sampler in which the'casing and piston provide flat sur~aces
which are sub3tantially at right angles to the longitudinal axis of the
sleeve and de~ine opposite wall~ Or the chamber when the casing, sleeve
and piston are in thelr ~lrst relative po.sition, the planes of the
flat ~urface~ lining up w:lth the ports at the perimeters thereor such
that rluid flowing throuKh one port and out through the other port has a
substantially uninterrupted path and wlthout there being substantially
any cavities in the chamber.
~ 5 ~ $~
ln onc particular arraneemcnt, bo~h ror is~kinc~c ~nd rJ~n-
1s~klnetlc ~ampllne, the ~all Or the 31eeve 1~ rorm~d with t~ port~oles
whlch alien one wlth each Or the two pvrt~ when the caslng~ sleeve and
plston are ln their rirst relative po~itlon, each p~rt 1~ the ~ame 3ize
as the porthole with which lt register~, and the arrangement Or the
sleeve and piston i9 such that they are moved together by the actuator
mean~ relatlve to the ca3ing during the chang~over from the fir3t to
the second relatlve positions of the casin~, sleeve and pi~ton b~t the
pi~on alone i9 moved further, in the Longitudinal directlon Or the
sleeve, durinK changeover rrom the second to the third relatlve positions.
This arrangement is advantageouq in that it merely requires the actuator
means to take the ~rm of a double-acting actuat~r and a lost-motion
device which becomeq operative after the ~leeve ha~ been arrested in the
second relative poqition Or the casing, sleeve and piston. To assist in
achieving isokinetic ~ampling with such a sampler, the ~leeve can be made
cylindrical and the-chamber bounded by two tran~verse circular plates
fixed to the inside Or the sleeve and meeting the inner ~urface of the
sleeve at the extremities of the porthole.
The caslng ~ay include a plug unted in the botkom region of
the casing and having a flat ~urface constituting a b~undary wall o~ the
chamber. The plug is advantageous in that it can be removed for enabling
the interior Or the chamber and the neighbouring internal regions to be
inspected.
A stop can be provided ~or arresting the sleeve rrom further
movement in the same direction after arriving in the ~econd relative
position Or the casing, 31eeve and piston ~rom the first relat~ve position.
The stop constitutes a simple and e~reotive way of arre~ting the motlon
Or the sleeve.
-- 6 --
One way Or handlin~ and collecting the sample e~ected from the
chamber i~ ror the said paA~a~eway to be rormed ln the plston and the
piston provid2d with a p~ston rod which extends to the inner ~leeve~ the
pas~age~ay beine extended to pa~ within the piston rod in the lonei-
tudlnal dlrection thereof and communicatlne vla a rlexible tube or plpe
with a receptacle for receiving rluid di~charged from the sampler.
One prererred embodiment, ~hich iY specially de~iened for
lsokinetic ~ampling, comprlses a ca~ing having two port~ in the wall
thereo~, the casing being capable in communlcation with the pipeline 90
that fluid in the pipeline can rlow into one port and out of the other
port, the axis of the pipeline being substantially at right angles to the
axis of the casing. A sleeve is reciprocatable within the caslnB and i9
provided with two portholes capable of aliening wlth the port~ in the
casing/ each porthole being substantially no greater in ~ze than it~
ad~acent port. The slee~e haq a chamber formed th~rein, at least ~hen
the port~ and portholes are aligned, the boundary Or the chamber
comprising a pair Or wall~, the plane~ Or which are sub~tantially at
right angles to the longitudinal axis o~ the ~lee~e and which when the
portholes are aligned with the ports of the casing meet at the portholes
at the perimeter~ thereof so that rluid ~lowing through one aligned port
and porthole ~Id out through the other aligned porthole and port has a
substantially uninterrupted path and without there being substantially
any cavities in the chamber. Finally, means are provided for removing
~rom the chamber fluid which has been collected there.
3~
-- 7 --
In U91n~ ~he sa~pler the sleeve 1~ ralsed or lowered ~ that
both p~rta and porthole~ ~re aligned. At thls ~taee rluid i~ flo~lng
through the sampler, enterlng throueh one p~rt Or the casing and
leavin~ by the other port. ~his rlOw i9 ~t constat ~elocity and at
the same velocity as the flow of fluid pas~in~ around the ca~ing.
Therearter~ the sleeve i~ ~hifted 90 that there i8 no l~n~r any pa3sage
of fluld through the sampler i~e. 7 the ports ln the casine are blocked
by the walls Or the sleeve. A sample of fluld is thererore trapped ln
the chamber and it can be removed rrom this chamber by the mean~ proYided
and 1t can then be analysed, lr de~ired.
In its simple~t rorm the casing and sleeve are of circular
cross-section and the ports and portholes are circular or oval. U~ually
the ports and portholes are dlametrically opposite one another. There
should be means to prevent relative rotation Or the ca~ing and the
sleeve 30 a~ to prevent the posslbility that the ports and portholes are
misaligned radially. - Qne such means comprise~ a protru~ion in tbe
ca~ing mating with a longitudinal channel in the slee~e. Alternatively
the easing can have a longitudinal ~lot or channel and the casing can
have a protruslon.
It is especially convenient i~ the sleeve i~ cylindrical and
the chamber rormed by two transverse circular plates fixed to the
inside Or the ~leeve and meetlng the inner ~ur~ace Or the sleeve at
the extremities Or the portholes, i.e., tanEentially. In thi~ manner,
there is no ~pread Or the fluid in the longitudinal direction of the
sleeve as the fluid ~lows straight throueh the chamber in a direction
which ~ at right angles to the longitudinal axi~ of the casin~ and
3~
-- 8 --
~leeve. Also th~ rluld ha~ an unlnterrupted flo~ throueh the ca~ing
and sleeve. Finally there are the m~ans for removlng ~rom the cha~ber
fluid whlch has been collected ln the ehamber. ~he simple~t form
would be a tap in the bottom Or the chamber whlch could be ~hut when
the chamber is being u~ed to collect f`luld and opened when fluid no
loneer rlows ~nto the chamber and it is desired to collect the fluld .
Although the above brie~ly de~crlbed sampler can be used for
var~ouq applicationq, in practice lt has been found necessary to use
a rather more sophisticated design Or 3ampler. Accordingly such a
fluid sampler comprises a casine havine a stop on the internal ~urrace
thereof and havin~ two ports in the wall thereor, the casing being
capable Or be~nB in communication with the pipeline so that fluid in
the pipeline can ~low into one port and out Or the other port, the axis
of the pipeline being substantially at right angles to the axi~ Or the
casing, the pi~ton sleeve having a base and in slidable contact with
the inner ~urface of said casing and having porthole~ therein adjacent
to the base thereof capable of aligning ~ith the ports of the casing,
each porthole beiDg substantially no greater in ~ize than its aligned
port, a piston in ~lidable contact ~ith the inner surrace of ~aid
sleeve moYable therein from a po~ition ~ust clear Or the portholes9
past the porthole~ to a po~it~on in contact with the ba~e Or the piston
sleeve, a piston~having a passageway therein extending the length
thereof, and resllient means enabling pressure on the piston to move
the sleeve and piston past the ports in the oasing until the base Or
the piston sleeves cDntact~ the stop of the caslng when ~urther pressure
on the plston ~orces the piston into contact with the base Or the
piston ~leeve..
33~
g
When depres31n~ the pl~ton and sle~ve in us1rlg the prererred
sampler o~ the lnventlon, the ports Or the easlng are elo~ed by the
plston ~leeve and a ~ample Or rluld is i~olated in the volume bounded
by the base Or the piston sleeve, the inner ~urface Or the c~sing and
the lower end Or the piqton. On rurther depre~sine the plqton 90 that
it contacts the base Or the piston sleeve the fluid is fvrced up through
the passageway in the pi~ton when it can be collected in a recepta~le~
In thi~ manner only a sinele do~nward short ~troke is required.
I~ is preferred but not es~ential khat the casing, sleeve and
piston are circular in cross-section. Thi~ ~orm is cheaper to make and
less likely to result in ~am~ing than if the cross-section were square
or rectangular. However, when the cross-section is circular there are
means to ensure that there is no relative rotati~n between the sleeve
and the casinB so that the ports and portholes can always be aligned by
shi~ting the ~leeve relatlve to the casing along their longitudinal
axis. Generally a mating longitudinal channel and protrusion achieves
this result.
Generally the casing should be elongate, i~e., be Or a
length considerably greater than lts diameter lr cylindrical or lts
greatest cross-~ectional dimension i~ not circular in cro~ sectlon.
. .
Lf~3~
The two port3 ~re u~ually near but not at the end o~ the ¢a31ng
9~ that there i~ ~pace ror the ~leeve to be depre~sed so a~ to close
the ports in the cas~ng. The casin~ has a ~top on the lnternal wall
thereor 30 as to preYent the pl3ton sleeve rrom ~liding pa~t the end
o~ the ca~ing and to enable rurther pre~ure on the piston to force
the plston lnto contact wlth the ba~e Or the piston sleeve. Thl~ stop
c~n be ~y lug or lnternal protru~ion, prererably at least two, but
the mo~t prererred 3top 1~ a ~eat collar, the outer dimensions Or
which are qubstantially the same a~ the ~nternal dimenslon~ of the
ca~ing. A particularly preferred form when the casing i~ cylindrical
is a collar with an external screw thread capable of` ~crewing into the
base of the ca-qing. It is essential that the stop does not close the
end Or the casing completely because it is necessary to permit
displacement o~ any fluid trapped below the base o~ the piston sleeYe
~hen the plston sleeve descends. Hence a seat collar ls particularly
suitable.
The two ports are prererably aligned i.e., diametrically
opposite one another ir the ca~ing is cylindrical. HoHever this is
not ab~olutely necessary and the ports could be located ~o that they
co-operate ~ith two ends of a pipeline which are at rlght aneles to
one another. It is particularly desirable however that the axis of
the pipeline is substantially at right angles to the axls o~ the
casing, the ax~s Or the casing being the direction in which pi~ton and
piston sleeve reciprocate.
33~
, ~
Il de~ired ~ch port cnn be provided with B flan~e ~ that they can
be bolted to.flRngeD.on the end6 of the p;peline. Pre~erably a ~al i6
interpDsed between the flange on ~ port and on-the pipeline.
. It is preferred however for the ~pler to be design~d so that ~t
can be inserted through a~ aperture in the pipeiine and suspended in the
pipeline.so that fluid ean llow through one port and out throu~h the
other port; Ihi~.can be achieved by fixing a socket to the-aperture,
the inner surfac~ of the socket having a screw thread. I~e upper portion
of the casing of the.sampler can be provided with a.screw thread which
co-operates with that of t~e ~ocket. AltPrnativeiy the upper end Df the
sampler can screw into a block, the upper end of the ~lock having the
yoke of a pneumatic actuator attached thereto.
. The piston sleeve must be capable of sliding within the casing and
there should be only the ~inimum gap between the outer surface of the
sleeve and.*he inner surface of the casi~g. I'he sleeve serves as a
valve to block the ports.of the casing and at the same time trap a
sa~ple of flui~ flowing-~hrough~he pipeline.
There are porthol~es in the s~eeve designed to be capable-of aligning
or Tegistering wi~h the ports i~.the cas;ng. This alignment is-achieved
by shifting the:sleeve longitudi~ally ~ithin.the casing l~ntil.the ports
aod porthDles are level with each other~ Each porthole should preferably
be the same ~ize as the port with which it registers. Prefersbly all
portholes and ports should be oval~ the longer axis being transverse to
the lon~itudinal.axes~.of the sleeve and casing~ Less desirably the
por~s aDd portholes are circular, ~uare or rectangular.
': " .
-- 12 --
The lower end of the ~leeve a6 provided with a bnse. Pre~rnbly
thi6 i8 ~chievea by thre~din~ internally the lower end of the slePve and
fitting it with ~ ~ealing plug.
Slidea~le with;~ the piston ~ieeve is a pi~ton. There i~ preferably
also a pi~ton rod ~lso havin~ a p~ssageway extending the length thereof.
~referably the pistoD ~leeve i6 provided with an end section opposite
the base thereof:so that this piston rod can pass through an aperture in
the top end section of the piston sleeve. In order to equalise press~re
pi~tDn ~leeves with end member~ should be provided with one or more
apertures, the~e preferably being located in the member itselfO
The passage~ay WithiD the p;ston (and piston rod) and extending the
length thereof is preferably`located centrally of the cross-section of
the piston i.e. along the axis ~hen ca6ing, piston sleeve and pis~on
have circular cross-~ection. The ~urpose of thi~ passageway is to allow
the ~ample of fluid to.be forced.out of ~he sampler when the-pistoR is
forced.i~to.-con~a~ with the base of ~he sleeve.
. The passageway i~ the piston or ~i.s~o~ rod is preferabl~ provided
with.a Don-return valve ~or ex~mple ball ~nd ~pring ~o ~hat there îs no
~low o~ ~he fluid being sampled passing ~o a receptacle or drnin back of
~ample.~luid.from.a.receptacle ~hen the ~ampler.is no~ being used.
The ~ilien~.means are preferably a compression sprin~ ~hi.oh m~y
be located:between.the pistoD sleeve aDd a shoulder formed on the
pi6ton Iod or..a.shoulder formed withi~ the casing. ~he shoulder formed
on.the piston rod if of the same diameter as the inDer diameter o~ the
casing ~an also act ~s a guide disc.for the pisto.n ~od. If ~he should2r
~ormed on the.piston rod ;c i~ ~lideable contact ~i~h the interior o~
,
33~
- 13 -
the ~a~ing then it ~hould.be pr~vided with ~ne lDr ~re ~pertures ~o a~
tv equslise the pressu~e both ~ides of the ~houlder.
~ he pass~geway should communicate with ~ receptacle ~or the Is~mple.
Since the piæton .move6 / the connecting tobe or pipe between the pas~ageway
and receptacle will usually be flexible. Alternatively it i~ possible
to haYe.an elongated aperture from the passageway in communication with
the connecting tube ~r pipe such that w;th the further move~eDt of the
piston after the piston sleeve has contactea the closed end there is
s~ill communication between the passageway and said tube or pipe.
..To.obtain a sample rom fluid flowiDg in a pipeline after the
sampler has been positioned in the pipeline with the portholes of the
sleeve aligned.~ith the ports of . the casing, pressure is exerted on the
piston ~ia the piston.Tod. .~his force~ down the piston a~d piston
slee~e, the latter clos;ng the ports o~ the casingS the pistGn sleeve
eveDtually contacting the stop of the casi~ urther pressure on the
piston forc~s.the piston do~n.f~lrther until it contacts the base o~ the
piston sleeve~ Ae ~he.~ame time the Isample of ~luid.originally;-trapped
~ithin.the con~ines ~f.the piston ~leeve i~ fDrced out of the ~aMpler
~hrough the passageway within:the piston and pi~ton rod.
Usually.the fluid will be a liquid, for example oil, but it can be
.a gas. I~ he case where ~ases are sampled it is preferred that the
wall of ~he piston be ~rovided with nn "O-ring" seal so ~hat ~here is no
leaka~e between the pisto~.and piston ~eeve and also for "O-ri~gi' seals
tu.be provided ~etween the piston rod n~d sleeve to prevent leakage near
the outlet ~ro~ the passageway.to the tube or pipe connected to the
receptaele. .In ~nct ~he presence of ~D O-ri~ ~eal~could be desirable
even when aampliDg 1;quids.
.. . .
33~
- 14 -
The ~ampler may be operated by a re1AtiYely s1mple c~n~rol
~ystem involvlne the u3e o~ compres~ed alr, a d1aphragm and solenoid
Yalves as wlll be descrlbed later.
The advantaees o~ the sampler are manifold. It can ensure
that it operate~ in accordance with lsokinetic princ~ple~ and there
are very rew moving parts or ~mall complex components. ~here 18
unlimlted compression po~er for po~itive in~ection. Al~o there i9
bi-directional operation~ and the quantity cr samp1e may be ad~u~ted
on-line~ Furthermore the sampler may be ea~ily coupled to a ~imple
pneumatic pulse integrator to log the number o~ samples taken~
A preferred rorm Or the fluid ~ampler Or the invention
i3 now de~cribed, by way o~ example, with reference to the drawings
in which :
Fig. 1 show~ a vie~ in part ~ection, o~ the top portlon
Or a sampler ;
Fig. 2 hows a ~ection throu~h the bottom port~on ~r the
sampler Or Fig. 1 ;
Fig. 3 to 5 ~ho~ di~grammatically the various positions
of the pi9$0n and p~3ton sleeve within the ca~inB as the piston and
piston ~leeve are depressed;
Fig, 6 to ~ show the sequence o~ operations wher~in the
sample Or rluid is automatically collected from a pipeline and
discharged from the ~ampler of Fig. 1 to 5.
Rererrine to Fig. 1 to 5 the cylindrical casing 1 is
provided with two oval port~ 2 and 3. The ca~ing 1 i9 provided
with a ~eat ring 7 ~crewed into the bottom thereof.
3~
- 15 -
Slldeable withln casing 1 i9 the pl~qton ~leeve 14, the lower end
of which ~s internally thr~aded and ~itted w'Lth a seallng plu~ 9. The
~sleeve 14 ha~ tw~ apertures 15 and '16 and to equali~e pres~ure each slde
Or the 31eeve and a central apert~re 17 to accommodate the piston rod 19.
The ~leeve 14 al90 has two diametrically opposed oval porthol~ 10 and
1~ the ~ame size as the ports 2 and 3 and capable o~ registering
therewith. Relative rotation bet~en casing 1 and ~leeve 14 i8 prevented
by a protru~ion pin 68 communicating with a longitudinal channel in
sleeve 14.
The piqton 18 into which piston rod 19 is ~crewed is provided with
an 0-ring ~eal 20 and an axially located passageway 21 ~hich extends the
length Or the pi~stoD 18 and plqton rod 19 . ~here are 0-rir~ ~seals 38
making a fluid-tight ~eal when the pi~ton rod ~lide~s in the block 35
form'Lng a shoulder 40.
Located within the pa~ssageway 21 i9 a non-return Yalve compri~qing
a ball 25 and a compression spring 26. Between the top Or the pl~ton
sleeve 14 and the shoulder 40 formed in the ca~sing 1 i~ a compression
spring 27. Aperture~s 28 ~nd 29 are ~or ~qualis~ng pressur~.
Further up the casing there iB an lnspection plug 41 and there
are also some ~urther O~ring seals 39 at the top of thç casing.
Surmounting the casing 1 is a sa~pler tran~qrer block 45 which is ~crewed
onto casing 1 by mean~ of ~screw thread 46. A standard pneumatic actuator
(includinK yoke 33) is indicated in Fi~. 1 generally as 44 and i~
~crewed into ~ampl~er tran~rer block 46 by thread 47.
~ here iB also an Lsolatlon Yalve 50 whereby when the ~ampler i~
removed ~rom the piLpeline 6 the aperture at the top Or the pipeline can
be sealed Orr.
The fi~mple ~f ~luid which i6 col~ec~ed em~r~e~ fro~ the top of th~
passa~eway 21 by means of nn e~ongated ~perture 42 which i~ ~lway6 in
CO~DUniCatiOn with ~onduit 43 which i~ connected to pipe-line 57.
Leakage of fluid in transferring from pass3g~way 21 to condu;t 43 i~
prevented by the 0-ring sea~s 39.
The stroke adjustment whereby the volume of sample can be altered
is by means ~f the nut6 48 and 49 indicated in ~ig. lo
Referring.t~ ~ig. 3 to ~ to obtain a sample it is necessary to
move the piston 18 and piston slee~e 14 upwards so ~hat the portholes
10 and.ll register with.the ports.2 and 3~ respectively9.as shown in
~ig. 3.
The presence ~f the compre~sion spring 27 located ~etween the
shoulder 40.and the top of piston sleeve 14 ~eans that wheD the piston
rod 1~ is moved upwards~ both piston 18 ~nd sleeve 14 asceDd together.
Likewnse when the piston rod 1~ is.depressed b~th piston 18 ~nd sleeve
14 descend to~ether. Therea~ter it is necessary ~o exert further force,
forciDg down the pist~ 18 aDd piston sleeve 14 until the sealing plug 9
o~ the latter.contacts the seat ~ing 7 o~ the caslng 1 as shown i~ Fig.
4.
. .The sample is trapped between the-bottom o~ the pis~on 18 and the
plug 9 of the piston sieeve 14. Further pressure on the pis~on ~od 19
results lD t~e piston 18 being .~orced down ln~o contact with the plug 9
af the sleeve lb as.shown iD ~ig. S, thereby forcing`the sample up the
passageway 21, ~hrou~h aperture 4~, conduit 43, p;pe-line 57 a~d to the
sample ~ceptacle.
3~ .
R~errin~ ~ow to ~ig. 6 ~ sigllal ~rom contro]ling e~emcn~L via
short ~ime de~ay unit.(not shown) eonnec&ed to li~e 51 immediately
eneJ~i~es so~eno;d S~. Tbi~ energi~in~ of the ~olenoid 52 cause~ ~pply
air ~rom reservDir 53 to pass to the di~p~ragm 549 this diaphra~m 54 and
a compression spring 58 forming part of a stan~ard pneumatic aet~lator~
Since this diaphragm 54.is.pressurised this causes the pi~ton rod 19~
piston 18 and piston s~eeve 14 to move downwards togethe~, compressing
compression spring 58~
Referxing t~ ~ig. 7:when the pressure in the diaphrag~ 54 ~eaches.
the region o~ 0;85 kg/cm2 the sealing plug 9 of the sleeve 14 will be
firmly seated on the seat ring 7 of the casing 1~ the sleeve holding the
~aptive sample.
Referring to Fi~. 8 as the pressure of the diaphra~m S4 rises the
pistoD 14 is DOW driveD down~ards, compressin~ the fluid and transferring
it through line 57 ~o the sample receptacle~
Just as full air pressure is applied to the diaphragm 54 the short
tim~ delay unit.has come to the end ~f ~he ti~e cycle and the eleetrical
sigDai is removed from .the s~leDoia valve`S2. The de-energising of the
soleDoid 52 vents the air.from diaphra~m 54 via the vent (Y~ on the
solenoid valve 52 and the compression sprin~ 58 causes the piston rod
l9,..piston 18 aDd piston sleeve 14 ~o mo~e upward.
