CA1093613A - Back pressure system for slurry pipline - Google Patents

Back pressure system for slurry pipline

Info

Publication number
CA1093613A
CA1093613A CA309,030A CA309030A CA1093613A CA 1093613 A CA1093613 A CA 1093613A CA 309030 A CA309030 A CA 309030A CA 1093613 A CA1093613 A CA 1093613A
Authority
CA
Canada
Prior art keywords
pipe
segment
valve
slurry
inlet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA309,030A
Other languages
French (fr)
Inventor
Jay P. Chapman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bechtel International Corp
Original Assignee
Bechtel International Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bechtel International Corp filed Critical Bechtel International Corp
Application granted granted Critical
Publication of CA1093613A publication Critical patent/CA1093613A/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17DPIPE-LINE SYSTEMS; PIPE-LINES
    • F17D1/00Pipe-line systems
    • F17D1/08Pipe-line systems for liquids or viscous products
    • F17D1/088Pipe-line systems for liquids or viscous products for solids or suspensions of solids in liquids, e.g. slurries
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/8593Systems
    • Y10T137/87265Dividing into parallel flow paths with recombining
    • Y10T137/87539Having guide or restrictor

Landscapes

  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Water Supply & Treatment (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pipeline Systems (AREA)
  • Air Transport Of Granular Materials (AREA)

Abstract

BACK PRESSURE SYSTEM
FOR SLURRY PIPELINE
Abstract of the Disclosure For use in providing back pressure in a slurry flow, a first pipe has an inlet for receiving the slurry and an outlet for discharging the slurry. A
number of inverted U-shaped second pipes communicate at their ends with the first pipe at respective, spaced locations along the length of the first pipe.
Each second pipe has a pair of spaced sides and each side has an orifice choke therewithin. The sides of each second pipe extend upwardly from the first pipe so that the second pipes are self-draining. A valve is provided for each second pipe, respectively, each valve being carried by the first pipe near one end of the corresponding second pipe. A generally horizontal third pipe is coupled to the first pipe in by pass relationship thereto. Valve means con-trols the flow of a slurry into either the first or the third pipe.

Description

109~ 3 ~ .

:
~ !' ~' :: 1 BACK PRESSURE SYSTEM
2 FOR SLURRY PIPELINE
. . I
: 3 Tnis inv~ntion relates to i~?rov~en~s in the control 4 o~ slur~ie3 as they flow fro~ one loc~tion to anot'~er and, ~.ore particularly, to a syst2~ for ?rovidin ~ack ~r2ssure in a slurry flow to ~i~imi~e deterioration Or the pi?ellne 7 tnrou<~'h whicn tne slurr~ flows.

,ll 109 3~ 1 3 1, , I I . BACKGROU~ OF I~E INVE~TION
2 1l In a sl~rry pipeline it is often necesQary to
3 1I provide back pressure to avold damage to the pipeline. Thls
4 back pres~ure i8 u~ually provided by one or more orifice 51 choke~ located to limit the velocity of flow of the slurry through the pipeline. If the back pressure must be varied, 7 Ithe system require~ more than one orifice cho~e.
8 I In conventional slurry pipeline system, the orifice 9 ¦chokeQ are placed in bypass pipes connected to a main or 10 ~central pipe with the bypass pipe~ being in a norizontal 11 ¦plan~. By controlling a number of valves near the bypass 12 ¦pipes, the slurry flow can be directed through ona or re 13¦ of the bypass pipeQ to vary the back pressure. Tne bypass 14¦ pipes are used because, under certain hydraulic circumstances, 15¦ the m~in pipe pressure upstream of the bypas3 pipes fall3 16¦ below ths vapor pres3ure of water which causes the fluid to 17¦ cavitate and fl4w at a higher velocity while only partially 18 filling the main pip8. This high v210city and cavitation 19 erodes the pip8 at an undesirable rate. To prevent tnis, 20 ¦ the slurry flow is shunted into one or more of the bypass 2l~ pipes, each of which contains a choke to incraase the bac~
22 1 prPs~ure in the pipe.
23 ¦ ~ecause the bypa~s pipes are in horizontal planes, 24 1 thay cannot adequately drain so that solids are collected in 25 them and totally or partially plug the bypass pipes. This 26 requires th_ system to be cleanad out ire~uently to assur~
27 I continuous operation. MorPover, the arrangement of DypaQs 28 I pipes in hori~ontal planes re~uire~ a r~latively large 29ll number of valves; specifically, at least three valves or 30¦~ each bypass pipe, respectively. For arhieving a wide range 31l 321ll 2~

" 1093~;13 of back pressures, a relatively large number of control valves are necessary, thereby lncreasing the cost and complexity of the conventional back pressure systems. A need has, therefore, arisen for an improved system for providing back pressure in a slurry flow in a simple manner while avoiding the problem of plugging as occurs in conventional systems.

SUMMARY OF THE INVENTION

The present invention substantially satisfies the aforesaid need by providing an improved back pressure system for a slurry pipeline including a first pipe having a fluid inlet and a fluid outlet; a back pressure device for each of a number of spaced locations, respectively, along the first pipe, each devlce including a generally inverted U-shaped second pipe having a pair of spaced, vertical sides and a pair of opposed open ends communicating with the first pipe.
Each second pipe has means for providing an orifice choke therein. A valve is provided for each second pipe with each valve being across the first pipe between the ends of the respective second pipe.
A more particular aspect of the invention provides a back pressure system for a slurry pipeline including a first pipe having a fluid inlet and a fluid outlet, the pipe de-fining a first path for a slurry flow between the inlet and the outlet. A plurality of inverted U-shaped second pipes are provided, there being~.a second pipe for each of a plurality of spaced locations, respectively, along the length of the first pipe. Each second pipe has a pair of opposed, generally parallel sides, the length of one side being greater than the length of the other side. The first pipe has a first segment and a second segment adjacent to each of the locations, respectively, with each segment having a horizontal part and a vertical part. The longer side of each second pipe communic-ates with the horizontal part of the corresponding first segment ~0~3613 and the shorter side of each second pipe communicates with the corresponding first and second SegmelltS at the jUl-CtiOII
of the vertical part of the first segment and the horizontal part of the second segment. A valve is provided for each first segment, respectively, the valve being on the vertical part thereof. ~n orifice choke is provided for each of the sides of each second pipe, respectively, the chokes being operable to provide back pressure for a fluid flow there-through.
In a preferred embodiment bypass means are provided to permit fluid flow therethrough to allow maintenance work on the orifice chokes and valves, if necessary.
Accordingly, this invention seeks to provide a slurry flow system having improved back pressure means which minimizes the number of control valves to achieve a vairable back pressure yet the system is self-draining and cannot be substantially plugged by accumulation of solids as in a conventional system.
With a single valve controlling the communication between each second pipe and the first pipe, the cost of the system is reduced with reference to the cost of a conventional back pressure unit and the system is self-draining to substantially eliminate plugging of the second pipes to thereby permit sub-stantially continuous operation of the system notwithstanding the possibility of high concentrations of solids in the slurry flows therethrough.
Others aspects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawings for an illustration of a prior art system and a system of the present invention.

- ~.

; ~ 10~31i13 ( I IIN THE DRA~ING: I .
2~1 ~
3 1l Fig. 1 is a top plan view, partly schematic, of a 4 ! back pressure device of the prior art;
S I Fig. 2 is a side elavatlonal view of a back 6 ~pressure device of the present invention; . :
7~ Fig. 3 is a top plan view of the device of Fig.
8 2; and ;
9 Fig. 4 is an end elev8tion81 view o~ the device O of FLg. 2 ~7~
8 . .
201 . ' . . . .' ~ 211 : -221 . ,:
243 . .

25~ . .
26~ . .
27 1 .
281 .
29 11 .

321l 5_ I1l A t~pical prior art device for providing back 2 11l pressure in a qlurry pipeline ls shown in Fig. 1 and broadly 3 1l denoted by the numeral 10. Device 10 typically includes a 4~lhorizontal first pipe 12 having an inlet end 14 and an 51l outlet end 15. Inlet end 14 is adapt~d to be coupled to a 6~source of a slurry and the outlet end is adapted to be 7lllcoupled to a receiver for the slurry. Pipe 12 has a series 8 lof valves 16, 1~, 20, 22, 24 and 26 at spaced locations 9 lalong its length. T'ne pipe also has a number of U-shaped 10 Isecond pipe~ 28, 30, 32, 34, 36 and 38 on respective sides 11 ¦o~ pipe 12. Each o~ these pipes 28-38 is horlzontally 12¦~disposed and has an ori~ice choke 40 in one of the sides 1~3 Ithereof. These ori~ice chokes provide bac1~ pressure in the 14 ~corresponding second pipes depending upon the closure of 15 ~certain valves.
16¦ Each second pipe has a pair of valves in respec-17¦ tive, parallel sides thereof to keep the flow out of such 181 pipe. For instanc~, second pipe 28 has a pair of spaced 19 sides 28a and 28b provided with valves 29. Similarly, second pipe 30 has a pair of valves 31, second pipe 32 has a 21 pair of valves 33, s cond pipe 34 has a pair of valves 35, 22 second pipe 36 has a pair of valves 37 and second pipe 38 23 has a pair of valves 39. - -24 ~nen it is desired to prov~dP no back pressure, 25 valves 16, 1~, 20, 22, 24 and 26 are open and valves 29, 261~31, 33, 35, 37 and 39 are closed. Tnus, tne slurry flow 27jlpath is directly through pip2 12 from inlet 14 to outlet 1~.
28~ en it is desired to have a relatively s~ll bac~ pressure, 3l 32 1, 11 Il j .
' 1, 1~3~jl3 such as 50 psi, valve 16 is closed, valves 18, 20, 22, 24, 26 and 29 are open, and valves 31, 33, 35, 37 and 39 are closed. Then, the flow is into pipe 12 through inlet 14, then through second pipe 28 in bypassing relationship to valve 16 and then back into first pipe 12 for flow through the remaining length of the latter to outlet lS.
For an intermediate back pressure, such as 100 psi, valves 20, 22, 24 and 26 and valves 29 and 31 are open and valves 16 and 18 and valves 33, 35, 37 and 39 are closed. In such a case, the slurry flow is into first pipe 12, through second pipes 28 and 30, and then back into the first pipe 12 for flow to outlet 15. In this case, two orifice chokes 40, those in second pipes 28 and 30, will operate to provide the back pressure for the slurry flow.
For a maximum back pressure in the system, such as 300 psi, valves 16, 18, 20, 22, 24 and 26 are closed and valves 29, 31, 33, 35, 37 and 39 are open. Thus, the slurry flow is into first pipe 12 at inlet 14, then through second pipes 28, 30, 32, 34, 36 and 38 in bypass relationship to first pipe 12. The slurry then re-enters the first pipe near inlet 15 and flows through the latter to the receiver.
It can be seen that three valves are needed per orifice 40 to obtain the flexibility of using each orifice choke individually. Valves 29, 31, 33, 35, 37 and 39 are needed to prevent plugging of the corresponding second pipes and each side of each second pipe requires a valve for this . purpose.

~:;

lU~;i3 .
1ll To avold the need for 90 mdny valves in a variable 2~lback pres3ure sys~em, the present ~nvention, shown in Fig.
31 2, has been provided, the system being defined by the I I
4~1numeral 50 and including a flrst pipe 52 having an inlet 54
5 land an outl~t 56. Outlet 56 is spaced belo~ the level of ¦
6 linlet 54. ~
7 First pipe 52 has undulations at spaced locations
8 along its lenOth. At each such location, pip2 52 has a -
9 first pipe seg~ent provided with a horizontal part 60 and a lollvertical part 62. Also at each location, pipe 52 has a 11 second pipe se~ent provided with a horizontal part.64 and a 12 vertical part 66. ~le up?er end of each vertical part 62 13 communicates with the corresponding open end of tne adjacent l4 ! horizontal part 64 of the next adjacent second segmen~ e I5¦ louer end of each vertical part 66 communicates with tne 16¦ corresponding open end of the horizontal part 60 of the next I7¦ ad~acent first seO~men~. The vertical part 62 o~ the various I8¦ first segments includa respective valves 68, 70, 72, 74, 76 ~9¦ and 78. The vertical part 66 of the last or downstream 20 ¦ second segment is connacted to a horizontal part Sl ~Fi~. 3) 21 ¦ which has a valve 80 near outlet 56. Similarly, hori~onta~
22 ¦ part 60 o~ the upstream first segment has a valve 8~ near 23 ¦ inlet 54. ~ `
24 1 For each pair of ~ir3t and second segments o~ pipe 25 ~¦ 5~ there is associated an inverted U-shaped second pipe 261 -provid~d with back pressure means therewithin. ~nus, system 27 ~ 50 includes second pipes 84, 86, 8~, 90, 92 and 54. Each 28 Isecond pipe is in.a vertical plane or otne~lse extends up l . l ,, .

1093~

Illand down for self-draining purposes. Typically, the second 2~pipes are in the same vertical plane. ~ach second pipe has 3 a pair of spaced, generally parallel sides 96 and 98 and 4 eacn of the sides has an orifice cho'~e 99 there~it'nin.
5 Typically, two chokes 99.are used in each second pi?e to 6 distribute orifice cho~e pressure loss and thus potentially reduce 7 levels and distribute wear when the bypass valve is closed, the by-8 valve being any one of valves 68, 70, 72, 74, 76 and 78. Side 9 ¦96 is longer than side 98; thus, tne lower open end of side
10 196 communicates with the horizontal part 60 OL the corresponding
11 ¦first segment and the lower open end of each side 98 communicates
12 ¦with thP function of the vertical part 62 of the corres?onding
13 first segment and the hori20ntal part 64 o~ the corres~onding
14 second segment.
A third pipe 100 is disposed in bypass relationship 16 to the first and second pipes. To this end, pipe lOO i~ ¦
17 generally horizontal and is in the same hori~ontal plane as 18 first pipe ~2 as shown in F~gs. 2 and 3. Pipe 100 has an 19 u?strea~ horizontal part 102 which is perpendicular to pipe 20 52 and communicates with pipe 52 near inlet 54. A valve 104 21 in horizontal part 102 control~ fluid flow thereinto. The 22 downstream end of pipe 100 is connected to and communicates 23 Iwith hori20ntal part 81 and has a valve 10~ to control 24 ¦slurry flow therethrough.
~ typical operation of system 50 provides that 2611eaC';1 pair o orifice chokes 99, i.e., the pair in each 271!seCOnd pipe, will provide a certain back pressure, such as 281'' 1 29 11 . I

3~1 32 'i1 '.

., I, 9.

lU9~
.I j 1~ 50 p~l. Assumlng no back pressure is desired, valves 104 2l and 106 are clo~ed and valves 68 throuOh 78 and valves 80 and 1l -3~32 are opened. The slurry flow path is then di-ected 4I through first pipe 52 including flow through the varlous s~first a~d second seg~ents. There will be no flow through 6 1l any of tlle second pipe9 84-94. Alternately, there can be 7~flow through third pip2 100 i~ no back pressure is desired.
s¦lIn such a cas~, valves 30 and 82 are closed and valves 104 9 ~and 106 are opened.
10 I l~nen it is desired to provide a low back pressur2, 11l such as 50 psi, valves ~0 and 82 are opened and valves 68, 12 104 and 106 are closed. In this case, the fluid Llow will 13 enter inlet 54, flow into second pipe 84 through sides 9S
14 and 98 thereof, and then into pipe 52 at the horizontal part
15¦ 64 of the second seg~ent corresponding to valve 68. Then
16¦ the flow wlll continue in the first pipe 52 and bypass the
17¦ remaining second pipes 86-94, as valves 7~ through 78 are
18¦ also open, unt~l the flow reaches outlet 56.
19¦ For an intermediate back pressure, such as 100
20 ¦ psi, valves 72, 74, 76, 7~, 80 and 82 are opened. Valves
21 ¦ 68, 70, 104 and 106 are closed. The slurry flow path will
22 then be into first pipe 52, then into second pipe 84 in
23 ~ bypas3 relation3hip ~o valve 68, then througn the next -- -
24 1 segment of first pipe 52, then into second pipe 86 in bypa3s
25 ~ relationship to valve 70, then back into first pip~ 52 and
26 1 con~inues in the latter until the flow reaches outlet 5~.
271~ -29 i~ : -311, ~

i', . .
, .

lv I, . For the ma~imu~ back pressure, such as 300 psi, 2l val~.es 80 and 82 are opened and va:Lves 63, 70, 72, 74, 76, ~~-3,78, 104 and 106 are closed. Then the slurry flow is through 4 jl all n~ the second pip2S 84-94 where an incre~ental back sl~pres.sure is de~elo?ed at the upstre~m sides of each orifice 6~ choke 99, respect~vely -7¦ --i A re~iew of system 50 show~ ~hat only a.single ¦ val~e is needed for each second pipe, respectively, rather g;ithan the three as requ~red in ths prior art sys~m 1~. :
10 ~Since the second pipes of syste~ S0 are in vertical planes, 11 ¦the ~olids in ~he slurry flow settle down when there is no 12 ~fl~ through an orifice choke 99 so that the solids ~oin the 13 ¦flo~.through pi~Q 52. Thus, each second pipe does not get :
14 plu~ged. Bypa~s pipe 100 is provided to allow repa~r wor~
on-~rifice cho~es 99 and the ~arious valves, if necessary, -. -17 ~ .
18 I . .
~ 19 I

231 .

22891 . ' .

30~ . .
31 . .
32 ' .
', . i 1 -11- !

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A back pressure system for a slurry pipeline comprising: a first pipe having a fluid inlet and a fluid outlet; a back pressure device for each of a number of spaced locations, respectively, along said first pipe, each device including a generally inverted U-shaped second pipe having a pair of spaced, vertical sides and a pair of opposed open ends communicating with the first pipe, each second pipe having means for providing an orifice choke therein; and a valve for each second pipe, respectively, each valve being across said first pipe between the ends of the respective second pipe.
2. A system as set forth in Claim 1, wherein each second pipe has one side longer than the other side, said first pipe having a first segment and a second segment for each location, respectively, each first segment extending between ends of the corresponding second pipe, each second segment extending from the end of the short side of a corr-esponding second pipe to the end of the long side of the next adjacent second pipe.
3. A system as set forth in Claim 2, wherein each first segment has a horizontal part and a vertical part, each valve being carried by the vertical part of the respective first segment.
4. A system as set forth in Claim 1, 2 or 3, wherein each side of each second pipe has an orifice choke there-within.
5. A system as set forth in Claim 1, wherein is included a third pipe coupled with said first pipe in bypass relationship thereto, and valve means for controlling the flow through the first and third pipes.
6. A system as set forth in Claim 5, wherein the inlet and outlet of the first pipe are in the same generally horizontal plane, said third pipe being substantially in said horizontal plane and having a first upstream part extending horizontally from the first pipe near said inlet thereof.
7. A back pressure system for a slurry pipeline comprising: a first pipe having a fluid inlet and a fluid outlet, the pipe defining a first path for a slurry flow bet-ween the inlet and the outlet; a plurality of inverted U-shaped second pipes, there being a second pipe for each of a plurality of spaced locations, respectively, along the length of the first pipe, each second pipe having a pair of opposed, generally parallel sides, the length of one side being greater than the length of the other side, said first pipe having a first segment and a second segment adjacent to each of said locations, respectively, each segment having a horizontal part and a vertical part, the longer side of each second pipe communicating with the horizontal part of the corresponding first segment and the shorter side of each second pipe communi-cating with the corresponding first and second segments at the junction of the vertical part of the first segment and the horizontal part of the second segment; a valve for each first segment, respectively, the valve being on the vertical part thereof; and an orifice choke for each of the sides of each second pipe, respectively, the chokes being operable to provide back pressure for a fluid flow therethrough.
8. A system as set forth in Claim 7, wherein is provided a third pipe in bypass relationship to the first and second pipes, and valve means for controlling the flow of a slurry through the third pipe.
9. A system as set forth in Claim 8, wherein said outlet is in the same horizontal plane as the inlet, said third pipe communicating with said inlet and being generally horizontally aligned with the inlet and the outlet.
10. A system as set forth in Claim 7, 8 or 9, wherein said orifices are spaced above the first pipe, the second pipes being generally coplanar with each other.
CA309,030A 1977-11-07 1978-08-09 Back pressure system for slurry pipline Expired CA1093613A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US05/849,061 US4230153A (en) 1977-11-07 1977-11-07 Back pressure system for slurry pipeline
US849,061 1977-11-07

Publications (1)

Publication Number Publication Date
CA1093613A true CA1093613A (en) 1981-01-13

Family

ID=25304969

Family Applications (1)

Application Number Title Priority Date Filing Date
CA309,030A Expired CA1093613A (en) 1977-11-07 1978-08-09 Back pressure system for slurry pipline

Country Status (7)

Country Link
US (1) US4230153A (en)
AU (1) AU519075B2 (en)
BR (1) BR7807013A (en)
CA (1) CA1093613A (en)
IN (1) IN150124B (en)
MX (1) MX148422A (en)
ZA (1) ZA784519B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492248A (en) * 1978-04-24 1985-01-08 Bechtel International Corporation Apparatus and method for slack flow elimination in a slurry pipeline

Also Published As

Publication number Publication date
US4230153A (en) 1980-10-28
IN150124B (en) 1982-07-24
MX148422A (en) 1983-04-20
ZA784519B (en) 1979-08-29
AU519075B2 (en) 1981-11-05
AU4087078A (en) 1980-04-24
BR7807013A (en) 1979-07-10

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