US2393750A - Impact dampener - Google Patents

Description

Jan. 29, 1946. D, 2,393,750

' IMPACT DAMPENER Filed S pt. 10, 1945, 2 She'ets-Sheet 1 Patented Jan. 29, 1946 UNITED I STATES PATENT OFFICE 2,393,750 I IMPACT DAMPENER David E. Carter, Oklahoma City, Okla. Application September 10, 1943, Serial No. 501,907 2 Claims. (cries-31) My invention relates to means for dampenin impacts, and more particularly to dampening means or shock absorbers for pulsating fluid con' veying lines.

In most pipe lines which are fed by pump pressure, other thanfrom rotary pumps,'the pulsation is insufiicient to cause any material damage tothe conveying line. -However, in some cases and in some types of fluid conveying lines, the constant pump pulsation is so great that the line becomes weakened and is finally broken.

One such caseis found in the drilling fluid line of usual rotary well drilling rigs. The drilling fluid in deep wells is often circulated under a normal line pressure of from 3000 to 4500 pounds per square inch. A portion of the drilling fluid or mud line consists of a section of rotary hose which connects the movable swivel and the stationary pump line. This section must be of hose because it most bepliable in order to be capable of compensation for alteration oradjustment in the height of the swivel in the derrick.

The fluid impact of the mud pumps materially increases the line pressure in the hose, the

blow often amounting to as much as 1000 pounds per square inch. It is obvious that a bursting im pact of this magnitude will greatly shorten the life of the hose when it is considered that this impact is repeated at every stroke of the pump,

and that in drilling oil wells, the mud pumps operate for twenty-four hours per day.

.The prime object of the present invention is to provide the mud line with a pump impact shock absorbing means which will dissipate most of the shock and prevent it from reaching the rotary hose.

Another object is to provide a shock absorbing means for the above described purpose which is automatic and positive in action; which is simple in construction; which is strong and durable; which is comparatively cheap to manufacture, and which has few moving parts to become worn and get out of order.

Other objects will be apparent from the following description when taken in connection with the accompanying two-sheet drawings, wherein;

Figure 1 is a fragmentary elevational view of a conventional oil well drilling rig, including a conventional drilling fluid hook-up, the device of the present invention being shown operatively installed in the mud line;

Figure 2 'is a fragmentary elevational view of the lower portion of the device; and,

Figure 3 is an elevational view of the upper portion of the device, parts beingbroken away to disclose the operative mechanism in partial section.

Like characters of reference designate like parts in all of the figures.

In the drawings:

The reference numeral l indicates as a whole, a conventional derrick mounted over a usual rotary table 2 which is adapted-to rotate a usual drill'pipe string 3; This string 3 is supported by a usual swivel 4 suspended from suitable elevating mechanism 5 and 6. The swivel 4 has a, hollow goose-neck 'l to which is connected one 'end of a section of usual rotary hose 8. The

rotary hose 8 extends from the swivel a desired distance. upwardly into the derrick where it is swingably mounted intermediate its ends to the derrick. The other end of the rotary hose hangs downwardly from its point of attachment to the derrick, and is connected to the upper end of an upstanding section 9 of pipe. The other end of y the pipe section 9 is in turn connected through pipe sections l0 and I l to the exhaust end of the conventional mud pump l2. The pump I2 is powered by a piston rod l3 driven to reciproca tion by a suitable steam chest I4.

The apparatus thus far described and indicated by the reference numerals I to M inclusive is not a part of the present invention, but have been shown in the drawings in order to illustrate the proper installation of my impact dampener, which will next be described in detail.

My impact dampener is indicated as a whole by the reference numeral (Fig. l) andis installed in the mud line. In the present instanceythe device is shown mounted upon a pipe T 2| by suitable pipe connections 22, 23, 24 and 25. I

The device per se consists substantially of a verticall disposed hollow stand-pipe havin its lower end threadedly engaged in the connection 25. The upper end of the stand-pipe 30 is connected by a pipe sleeve 3| to the lower end of a hollow cylindrical piston housing 32 havin a smoothly dressed inner surface 33. The upper end of the housing 32 is attached by a pipe sleeve 34 to the lower open end 35 of a dome 30. The upper end 31 of the dome 36 is closed, and its exterior surface is equipped with a suitable loop or stirrup 38 whereby the device may be engaged by suitable hoisting equipment, not shown, in order to facilitate its movement as a whole, if desired.

With the device installed as shown in Fig. 1, any fluid impact from the pump will reach the stand-pipe 30 before it is delivered to the hose 8. This is obvious because the stand-pipe is open 7 to the mud line, and lies between the pump and the rotary hose. e

As a means for absorbing or dampening the pump impact which is travelling along the body of drilling fluid from the pump toward therotary hose, the piston housing 32 is equipped with the following described mechanism:

Withimthe sleeve.3.4 and rigidly heldin placeby the adjacent "ends ofthe housingq3-2 and. the dome 3'6 there is provided a flat metal disc4ll bushing 4|. A piston rod 42 is slidably mounted within the bushing 4| and has a nut 43 and lock nut 44 upon its upper end to limit downward.

movement of the rod. Thelower endof'the rod 42 extends downwardly withinthelrousifigffli and is equipped with a conical nut 45 and locknut 46 for holding a piston head 41 upon the rod. Anompression springi48 is provided: aroundither rod: 4-2 between.-the-.disc 41llr'and-the uppenend of: the piston head 47. Cups 49 and B are provided around:- thet rod 42: for seating; the. ends of; the

spring 48 in an obvious manner;

pand'gradially; when: fluid "pressure is. exerted."

against'thetlowenendiof the head covering.

The: pistonghousing .32 is provided .witlr-an. out: let or b-reathereopening' 537wl'1ichspermitssintake1 and eidiaust. ofiairsaboveatheipistonu- 7 Operation Witlr: thez device-4 installed. in''' thee drilling fluid:

linesbetween 'the. pump: andJtherotary hose; substantially as shown in: Fig. thei-stand-pipe 39 will be filled: withiair, and since'the piston. 41: completelyclo'ses tlieupper end" of theist'and pipe, this'air is'v trapped against; escape; The

blow of each pump impact which .is exerted upon the fluid in: the line (pipes'-l0 andt I! willbe imparted to the body of trapped' air'in the 'stand pipe; Since'air is to some extent'a compressible fluid, tliefl-uid impact will partially compressthe air-in thestand-pipe. If the impact is suflicient; the compressed air-will force' thepiston 41 'up1- wardly against the resilient pressure; oi the spring 48'.

Since: air, although to some extentcompressible, is" more-or less limited in its compressibility; it'would be necessary'to entrap a great volume of it in order for the air alone to give a suffi ci'ent' cushion to entirely dampen thepump impact". The provision of'thespringretardedpis having a central bore which receives a bearing ton, however, increases this cushioning effect to such an extent that the stand-pipe 32 does not have to be burdensomely large in cubical content.

For instance, the above described dampening structure will function efliciently with the standpipe completely filled with the non-compressible drilling fluid. For such manner of operation, the upper end of the stand-pipe will be provided with-.a,bleeder openings: Theopening- 54 will be equipped-withia pipe =55f and a .shut off valve 56 for bleeding olT the air originally residing in the stand-pipe below the piston. Opening of the bleederline will permit the drilling fluid to enter and completely fill the stand-pipe up to the bottom. end; of. the piston 41. Under this arrangement pump impact will be directed through the 'column of-idrilling fluid in the stand-pipe directly, against the piston, and the spring 48 willth'erefore act as a sole means for dampening such/impacts e Wherrthe device;isQtmbecopseratedtinlthesmane nerlastr'above. described, the? stamii-pipe ialfnmay be materially shortened without loss ofiefiiciencyi- In i fact; thei'slia-ndepipeififli could; well be eliinimated; and. the? piston: housing: 32' couldf be mountedidirectly into: the;- pipetconnection 15. In this instance the "opening 54 .would be placed in the elemenlzi z4 witliithelbleeder' pipe: Sil con necte'dthereinl: c v 7 It is pointed tout that" the'::piston*and retardfng spring "arrangement :is isuch in bothrot the above de'scribedi'embodiments offthe present dev-ice'; tliat' the pump impact will "be efli'cientIy dampenedbe fore it can reach-the rotary li'ose 8% 7 llclaim:

1.- The combination witha. fiui'd conveying lihe carrying a. pulsating I fluid pressure, of a pulsation' dampen'er including: :an air. chamber havingone endt in communication with said line-y a -pis'= ton in'saidchamber andElbsingtlie oth'enen'd portion thereof for entrapping ai r" tl'ierei'ng said piston adapted to be moved by pulsations in :the line being exerted' upon the entrapped air in said chamber; resilient means for" retarding movement of the piston: and ane escape verit fiir "airfor permitting free 'movement of said resilient; means;

2'. The combination with a=-fliiid-"conweyingline=' carrying: a pulsating'fiuidpressure, ofia pulsatiom .dampner including: an air chamber having one end in communication with said lin'e; a;- piston in said chamber and closing the: other en'dportion thereof'for entrapping'air 'therein, saicl piston adapted to bemoved bypuls'ations in theline" being exerted upon the entrapped air in said" chamber; a spring for retarding movementof 'the" I piston; and an escapevent for aii'Torper-mitting free movement ofi said spring:

DAV-ID CAR PER

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