US2059631A

US2059631A - Well cleaning device

Info

Publication number: US2059631A
Application number: US22282A
Authority: US
Inventors: Weldon C Erwin
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-05-20
Filing date: 1935-05-20
Publication date: 1936-11-03
Anticipated expiration: 1953-11-03

Description

Nov. 3, 1936. W, C, ERWm 2,059,631

WELL CLEANING DEVICE Nov. 3, 1936. w. c. ERwlN WELL CLEANING DEVICE Filed May 20, 1935 4 Sheets-Sheet 2 Mela/an, Clf'rwl 4 Sheets-Sheet 5 Nov. 3, 1936. w. c. ERWIN WELL CLEANING DEVICE Filed May 20, 1935 M/Mw Nov. 3, 19,36.

w. c. ERWIN 2,059,631

WELL CLEANING DEVICE Filed May 20, 1935 4 Sheets-Sheet 4 ntented Nov. 3, i936 WELL @LEARNING DEWE Weldon C. Erwin, Huntington Farb, (Dalit, assigner to John Grant, Los Angeles, alif.

This invention has to do generally with well cleaning devices and is more particularly concerned with such devices wherein there is provided a low-pressure-holding or charge-receiving chamber with a normally closed inlet adapted to be opened at predetermined points in the well whereby the well fluid, under relatively high pressure, charges that chamber with sand or other foreign matter adjacent the inlet, or sets such pressure actions or high velocity uuid-movements as to dislodge foreign matter which may be offering obstruction to free passage of fluid through fissures in theformation or perforations in the well casing.

While the invention is here described in connection with a device having a single-charge low-pressure chamber adapted to be emptied after each charging and after the tool has been lifted from the Well, it will be understood the illustrated inlet valve for said chamber and the valve-control mechanism may be applied with advantage to the inlet of any type of low pressure chamber, irrespective of the manner in which the charged chamber is subsequently emptied or prepared for re-charge, and therefore the showing of the invention as embodied. in connection with a particular type of chamber is not to be considered as limitative on such broader aspects of the invention.

In this connection it is to be noted that in dislodging foreign matter from casing perforations or otherwise promoting fluid flow by setting up uid movement by the charging of the receiving chamber, (as distinguished from bailing) the matter so dislodged is ordinarily, but not necessarily, forced into the charge receiving chamber and subsequently disposed of along with the iiuid charge.

The device will here be described as utilized in the cleaning of casing perforations, to which use it is particularly well adapted, but this particularized description is not to be considered as in any way limitative on the adaptability of the device for other cleaning operations.

The invention may be more particularly characterized as being directed to cleaners of the general-type comprising the subject-matter -of a copending application, Ser. No. 5,774 .filed Feb. 9, 1935 by James T. Barkelew and Harold E. Scantlebury on Well cleaning device (D). That application describes an inlet valve assembly for the low pressure chamber, wherein one valve element overlies a portion of the other valve element to form a seal, both elements being movable with respect to the body member and' both being so exposed that well pressure tends to move them upwardly. The overlying element, however, is latched down in a manner to resist movement under the influence of the well pressure, it following that such pressure is effective s to set up relative movement between the elements in a manner to seat the underlying element on the latched element.y

Accordingly, as the tool is lowered to zones of increased pressure with a consequent increased 10 tendency for leakage between valve parts, the tighter is the valve held closed to resist such leakage, an obvious advantage. Then, when the overlying element is unlatched after the tool reaches the predetermined zone of operation, l5 well pressure is eective to move both elements upwardly, but the upward movement of the underlying member is checked before that of the overlying element, it following that the elements are relatively parted to open the inlet 2o of the low pressure chamber. V

One of the characteristic differences between the present invention and the invention described in application Ser. No. 5,774, is that whereas the specific disclosure in that case il- 25 lustrates a valve assembly in which the valve seat overlies the valve plug, and the seat movesrelatively upward from the valve to open the low pressure chamber, in the present instance the valve plug is the overlying element and 30 moves upward away from the seat after the travel of the latter has become arrested. The present invention also embodies a. novel by-pass valve construction wherein the by-pass valves are operated directly by movement of the low 3 pressure chamber valve, in my preferred construction the by-pass valves being connected integrally with the low pressure chamber valve.

The various features of the invention, as well as numerous additional objects and aspects will be fully understood from the following detailed description.

Throughout the description to follow, reference is made to the accompanying drawings, in which:

Fig. 1v is a side elevation of a cleaning device embodying the invention;

Fig. 2 is an enlarged section on line 2-2 of Fig. l;

Fig. 3 is an enlarged section on line 3-3`of 50 Fig. 1, the showing of the inlet valve member of Fig. 2 being here repeated in order more clearly to relate certain of the parts;

Fig. 4 is a section on line i-ll of Fig. 1, and representing a downward continuation of Fig. 3; 55

Figs. 5 and 6 are sectional views similar to Figs. 3 and 4, showing the parts in changed positions;

Fig. 7 is a view showing the low pressure inlet valve in full open position;

Figs. 8 and 9 are views similar respectively to Figs. 5 and 6, and showing the parts in still different positions; and

Fig. 10 is a section on line III-I0 of Fig. 5.

As has been previously stated, the cleaning device is particularly well adapted, but not limited, to the dislodgment of foreign matter from the perforations of well-casing, and therefore I have illustrated the device as positioned within such a perforated casing or screen A having any suitable type of perforations, here conventionally illustrated at B. Body member C of the cleaning device is here shown as made up of a plurality of sections coupled end-to-end, though it will be understood the showing of such sectional characteristics is not to be construed as limitative on the invention.

'I'hreadably connected body or casing sections are indicated at I0, I I and I2; section I0 (Fig. 2) serving as a head or top closure for the chargereceiving or low-pressure chamber D which is annularly defined by those sections. Attachment section I3 is threadably connected to section I0 and serves as means whereby the body member may be attached to a suspension element-cable I4, for instance. Section II, here shown as lon gitudinally contracted, may be of any desirable length and may, itself, be sectional. A forty foot length gives chamber D a capacity ample for most operations.

Section I has a reduced axial bore I5 from which extends a transverse passageway I6 controlled by a spring-closed, outwardly-opening relief valve generally indicated at I1. I'he function of this valve is merely to relieve high pressure in the charge-receiving chamber as the tool is raised into zones of lower pressure. To facilitate unloading of chamber D, I preferably provide an inwardly opening, spring-closed dump relief valve at I8. This valve is fully described and claimed in the copending application of W. C. Erwin et al. on Well bailers, led April 22, 1933, Ser. No. 667,439 wherein the Valve showing is substantially identical to the instant showing. It will suillce here to state that removable screw plug I9 normally closes passageway 20. When chamber D is to be unloaded, plug I0 is removed and passageway 20 is then adapted to put that chamber into communication with the atmosphere when the negative pressure therein (as created by the dumping of the fluid) is of a value 4allowing spring-closed valve I3 to open under atmospheric pressure.\

While, as will appear, chamber D may be unloaded by opening a valve which has dual capacity as an inlet closure and foot-valve, I have here illustrated an unloading door independent of and above said valve, the choice as to which dumping means shall be employed lying with the operator. The illustration of these two dumping mediums therefore is not to be considered as limitative of one on the other or as indicating that both are necessary.

'I'he auxiliary dump is here shown as a removable door 2l provided in section I2, the construction and mounting of this door being duly described in said copending application, Ser. No. 667,439, in which the showing of the door is substantially identical with the instant showing and which application contains claims to these features.` The door is opened by loosening screws 22 (which normally press the door inwardly t0 compress gasket 23 and thus provide a duid-tight seal) and then sliding the door transversely to clear lugs 24 from overhanging lips 25, which lips define way 26. Screwed into and depending from section I2 is a tubular section 21 containing a valve-assembly, generally indicated at V, adapted to function alternately as an inlet valve and a foot-valve for chamber D, as will appear, though this dual capacity is not to be considered as limitative on certain aspects of the invention.

Reduced diameter tubular section 28 is screwed into the lower end of section 21, serving as a depending extension thereon, or the lower continuation of body portion C. A packer-carrying sleeve 29 is screw-threaded at 30 orn the lower end of section 28, and the bottom of the sleeve is closed by a shoe 3| which may conveniently be formed integrally with the sleeve, as illustrated. Body section 28 carries a pair of vertically spaced packers, generally indicated at 32 and 33, the

ilatter being held stationary against longitudinal movement on the body, whereas packer 32 is permitted a limited amount of longitudinal travel relative to the body, for purposes that will later develop. Between

packers

32 and 33, body section 28 is provided with a series of openings or perforations 34 communicating with an annular space 35 between the body and casing A, and dened verticallyby the packers.

As previously mentioned, the invention in its broad aspects is not regarded as being necessarily limited to cleaners involvingthe use of two or any particular number of packers, although the illustrated arrangement is preferred and well adapted to a description of the invention in a typical embodiment. Additionally, it is to be observed that the invention is not concerned with or limited to the use of packers of any specific type or construction, and that I may employ any form of packers capable of confining an annual space between the body and casing, as at 35, and by way of which a relatively localized pressure differential may be applied to the casing apertures in the operation of the cleaner, as hereinafter ex-A plained.

The lower packer 33 is shown to comprise a cup leather or rubber 36 held against annular shoulder 31 of sleeve 29 by cup-shaped member 38, the cup leather and member 38 being clamped tightly in position by nut 39 on the upper end of the sleeve. The packer 36 may be reenforced in the usual manner by spring wire 40. The upper packer 32 is generally similar in construction, and comprises a cup-shaped packing 4I seating in -a cupped member 42, both being carried by a sleeve 4.3 movable longitudinally on body section 28. PackingI 4I and member 42 are tightly clamped between shoulder 44 on the lower end of the sleeve and spacer sleeve 45 by nut 46 threaded on the upper end of sleeve 43. The uppermost position of the packer assembly relative to-body section 43 is limited by the engagement of the.

upper end of sleeve 43, or nut 46, with stop collar 41 secured to the body by set screws 48.

The Valve assembly for controlling the inlet R of chamber D, is generally indicated at V and' comprises a tubular valve seat member 49 slidable vertically within body bore 50 and yieldably supported by coil spring I seating on a ring 52. Member 49 is -limited in its upward movement within the body by engagement with a shoulder 53 at the upper end of bore 50. For reasons that will later appear, it is desirable to prevent uid leakage upwardly between member 49 and body section 21, and for this purpose the member is provided with a suitable fluid pressure expansible packing 54 retained by nut 55, the effect of uid pressure communicated from body passage 56 to the outside of member 49 being to force the packing 54 into fluid-tight engagement with the body and thereby prevent leakage upwardly into the low pressure chamber D.

Normally, the lower end of chamber D is closed by a valve 56 engaging the upper end of seat member 43 and attached to a rod 51 depending within the body to a point below lower by-pass ports 58 formed in sleeve 23 and body section 28 below the lower packer 33. Upper by-pass ports 53 are formed in section 28 at a convenient point above the upper packer 32. In raising or lowering the cleaner, it is desirable to by-pass the well liquid standing in the casing A, past the

packers

32 and 33 in order to avoid well fluid resistance to movement of the cleaner that would otherwise result from the fluid-tight engagement of the packers with the casing. Accordingly, by-

pass ports

53 and 53 are provided in order that as the cleaner is lowered, the well liquid may by-pass from below lower packer 33 up through body passage 56' and then out through ports 59 into the casing above upper packer 32; and oppositely as the cleaner is being withdrawn from the Well.

During such time as the cleaner is drawing its charge of well fluid upwardly into theflow pressure chamber D, it is desirable that by-

pass ports

58 and 59 be closed in order that the full elect of the pressure dierential may be conned to the annular space 35 enclosed between the packers. For the purpose of controlling the by-pass ports so that they may remain open while the cleaner is being raised or lowered, and closed while the cleaner is receiving its charge of well fluid, I provide a pair of slide valves 60 and 6I threaded at 62 and 63 on the valve rod 51 and having open passages at 64 to permit free passage of well uid longitudinally through the valves. Both valves 60 and 6I act simultaneously to open the by-pass ports, see Figs. 3 and 4, or to close the ports as illustrated in Figs. 'I and 9.

Valve 56 is releasably held in closed position, and by-pass valves 60 and 6| in open position, by a latch device generally indicated at 65, which operates to release the valve assembly for upward movement relative to the body, as a result of upward body movement relative to sleeve 43. The latch assembly 65 comprises a sleeve 66 capable of limited vertical movement on body section 28 but held against rotation thereon by pin 61 secured to section 28 and projecting within a straight vertical slot 68 in the sleeve. The latter is yleldably supported on a coil spring 69 bearing at its lower end against collar 10 removably fastened to the body by set screws'1l. Formed within sleeve 66 is a pair of cam slots 12, see Figs. 3 and l0, each having an upper substantially straight vertical portion 12a, an intermediate angular portion 12b, and a comparatively short vertical bottom portion 12e. In the position of Fig. 3, the lower extent of portion 12a of each sleeve slot registers with the upper end of an associated slot 13 in body section 28, each of the two slots 13 (Fig. 10) comprising a vertical portion 13a and lower portion 13b extending laterally from the lower' end of 13a.. In Fig. 3 the upper edge 13c of portion 13b of each body slot (which edge may be considered as a body shoulder) is shown to be inclined, the degree of inclination being at about or somewhat greater than the slip angle.

Threaded at 16 on the valve rod 51 is a sleeve 15, the sleeve having vertical passages 11 (Fig. 10) through which the well iluid may flow. Pins 14 are carried by sleeve 15 and project outwardly through body slots 13 and slots 12 in the sleeve 65, the pins being locked in the slots in the posi-f tion of Fig. 3 to hold the valve assembly against upward movement within the body, but being releasable from locked engagement within the slots as a result ofdownward movement of sleeve 66 on the body as will now appear.

In operation, the cleaner is lowered in the well on cable I4 with the parts set in the positions illustrated in Fig. 3, valve rod 51- having been pulled down and, through valve 56, depressing the valve seat member 49 to compress spring 5l,

members

49 and 56 thus closing off passage 56 from communication with chamber D. Pins 14 are thrust into the ends of lower portions 13b of body slots 13, movement of thepins to this position being permitted by moving sleeve 65 down against the resistance of spring 69, sumciently to allow the pins to follow the intermediate portions 12b of the sleeve slots into the ends of slots 13b. It will be noted that by their engagement with the lower portions 12e of the sleeve slots, pins 14 are prevented from backingout of the body slots 13b, see Fig. 3, and that in this position the pins are held against upward relative movement within the sleeve slots 12 by their engagement with the inclined edges 13c of the body slots. Thus the two

slots

12 and 13 form an interlock holding pins 14, valve rod 51, valve 56 and seat member 49 against vertical movement within the body, valve assembly V thus being maintained in a condition closing inlet R.

As the cleaner is lowered within the casing A, the upper packer assembly 32 is forced down with the body by the engagement of the sleeve 43 with collar 41. 'I'he cleaner is lowered until the apertured section of the body between

packers

32 and 33 is brought opposite the particular section of the perforated casing to be cleaned,

bypass ports

58 and 59 remaining open all the while. The body C then is raised by the suspension cable I4 to bring the upper end of sleeve 66 into engagement with the lower end of sleeve 43, up-

ward vertical movement of the latter being'.l checked or retarded by the engagement of packer 32 with the casing. Further upward movement of sleeve 66 is arrested when that sleeve engages sleeve 43, whereupon continued elevation of the body and valve assembly V acts to withdraw pins 14 from the bottom portions 12o of the sleeve slots. Then, if the angle of edges 13c is no greater than the slip angle, continued upward movement of sleeve 66 causes theupper inclined edges of slot, portions 12b to cam pins 14 to the left, as viewed in the figures, the pins being pushed upwardly along edges 13c until the valve and rod assembly has been rotated sufficiently to bring the pins from beneath shoulders or edges 13c' and into line with vertical slot-portions 12a, and 13a.. Onthe other hand, if shoulders 13c are greater than the slip angle, the well pressure as directed against the underside oi the valve and rod assembly will move that assembly upwardly,l shoulders 13c camming pins 14 to the left as fast as the left hand edges 12g of slot portions 12b will allow it during continued and controlled relative upward movement of sleeve 56, the pins ultimately lining up with vertical slot portions 12a and 13a.

It is obvious of course that due to the high pressure diierential existing between the charge receiving chamber D and the interior of the body below the valve 56 there is a iluid pressure force of considerable magnitude inl addition to the thrust of spring 5|, tending to raise the valve seating member 49 and the valve and rod assembLv. While the rod 51 is held in the position of Fig. 3 by the latch 65 as the cleaner is lowered, the uid pressure applied to the lower end of member 49 acts to seat the valve 56 more tightly as the fluid pressure increases.

When pins 14 are in line with slot portions 12a and 13a (and thus clear of body shoulder 13e) valve rod 51 is released for upward movement within the body, with the result that iluid pressure applied to member 49 and the bottom surfaces of valve 56 and stem 51 suddenly projects the assembly upward to the point of engagement of member 49 with shoulder 53, see Fig. 8.

During this interval, as well as the interval during which pins 14 travel from bottom to top of shoulders 13e, slide valves 6|! and 6| are carried upward by the valve rod to the points at which they close the by-

pass ports

58 and 59.

The continued application of fluid pressure to the undersides of valve 56 and stem 51 causes the latter to travel on up after movement of the valve seat 49 has been arrested, to the fully open position of Fig. 7, the by-pass ports still remaining closed. 'I'he instantaneous opening of valve 56 and opening of communication between low pressure chamber D and body passage 56', causes, in effect, a violent suction to be communicated through the body apertures 34 and space 35 to the casing perforations B, producing a sudden rush of well liquid into the casing through the perforations, which dislodges clogging particles from the perforations, causing such particles to be drawn into the space 35. The charge then flows into the body of the cleaner and upwardly through passage 56 and the bore of member 49 into chamber D. 'I'he inflow of charge continues until a substantial pressure balance is reached in the charge receiving chamber D, whereuponI the valve and rod assembly, which is unsupported except for whatever friction there may be between by-pass valves 6l) and 6| and body section 28, drops to the position of Fig. 8, in which position valve 56 seats on the upper end of member 49 to close the lower end of chamber D and seal it against leakage of the charge, though it will be observed the by-pass ports remain closed.

During the elevation of the charged cleaner, there arises a dinerential between the internal and external pressures imposed' on the cleaner body, but relief valve |1 allows a bleeding of chamber D to reduce the higher internal pressure and thus eliminate danger of bursting and allows subsequent unloading without danger or inconvenience to the operator. This same pressure diierential resulting from the elevation of the charged cleaner acts upon the valve parts in the position of Fig. 8, iirst to press valve 56 and seat 49 down against the resistance of spring 5|, at the same time opening slide valves 60 and 6I to permit downward by-pass of the well liquid through

ports

59 and 58. Thus, during withdrawal movement of the cleaner, reopening of the by-pass ports may be considered as delayed with respect to the initial re-closing of valve assembly V. The positions of the parts at the point after the by-pass ports have been reopened are as shown in Figs. 5 and 6. Here it will be noted that spring 5| has become fully compressed. that is, compressed to a degree such that further downward movement of seat 49 is arrested, with small amount of clearance remaining at 14a between pins 14 and the lower ends of slots 13. By thus preventing further downward movement of seat 49 before pins 14 reach 5 the lower ends of slots 13, any possibility of the charge receiving chamber D becoming dumped as a. result of seat 49 moving downward with relation to valve 56, is prevented.

After the cleaner is fully withdrawn from the well, chamber D may be unloaded by opening door 2| to discharge the material thereabove, such built-up internal pressure as'remains in the chamber and generally as measured by the strength of the relief-valve spring, giving the material an initial outward impulse. To prevent a substantial negative pressure from developing in the chamber which would otherwise prevent complete unloading, plug |9 may be removed to permit inflow of air through valve I8 to the top of chamber D. With. chamber D emptied of its charge, spring 5| will of course raise the valve assembly to the position of Fig. 8. The latch 65 may then be reset in preparation for relowering the cleaner for a subsequent operation, by pulling the valve rod 51 down (for in- Stance, by inserting hand-hold members, not shown, into openings 14h in pins 14) to bring pins 14 to the lower ends of slots 13, and then turning the pins into the horizontal portions 13d of the slots by elevating sleeve 66 which through slot portions 12b cam the pins to the right, as Viewed in Fig. 8, thus returning all parts to the condition of Figs. 3 and 4, spring 69 yieldably holding the' sleeve 66 up so pins 14 are taken in slot portions 12e and thus releasably retaining latch 65 in holding position.

` While I have illustrated and described the preferred embodiment of my invention, it will be understood this is to be considered as illustrative of and not limitative on the broader aspects of the invention, for various changes in design, structure and arrangement may be made without departing from the spirit and scope of the appended claims.

I claim:

1. In a well-cleaning device, a body having a low pressure chamber and an inlet therefor, a seat member and a closure member cooperating to control fluid flow through the inlet, both said members being movable upwardly with respect to Said body, and said closure member being movable upwardly with respect to said seat member to open the inlet.

2. In a well-cleaning device, a body having a low pressure chamber and an inlet therefor, a seat member and a closure member cooperating to control fluid ow through the inlet, both said members being movable upwardly with respect to said body, and said closure member being movable upwardly with respect to said seat member to open the inlet, and said closure member' being adapted tol seat by gravity to close the inlet.

3. In a well-cleaning device, a body having a low pressure chamber and an inlet therefor, a seat member and a closure member cooperating to control iiuid ilow through the inlet, both said members being movable upwardly with respect to said body and said closure member being movable upwardly with respect to said seat member to open the inlet, and releasable means adapted to hold said members against such movement.

4. In a well-cleaning device adapted to be lowered through a well casing, a body having a low pressure chamber and an inlet therefor, a 75 aocaesr Seat member and a closure member cooperating to control iiuid flow through the inlet, both said members being movable upwardly with respect to said body, and said closure member being movable upwardly with respect to said seat member to open the inlet, and means shiftably carried on the body and operatively connected to one of said members to releasably hold the members against such movement, said holding means being adapted to be released by virtue of predetermined movement of the body with respect to the casing. y

5. In a well-cleaning device adapted to be lowered through a well casing, a body having a low pressure chamber and an inlet therefor, a seat member and a closure member cooperating to control uid flow through the inlet, both said members being movable upwardly with respect to said body, and said closure member being movable upwardly with respect to said seat member to open the inlet, and means shiftably carried on the body and engaging the casing, said means being operatively connected to one of said members to releasably hold the members against such movement, said holding means being adapted to be released by virtue of withdrawal movement of the body with respect to the casing.

6. In a well-cleaning device, a body having a low pressure chamber and an inlet therefor, a seat member, means yieldably supporting said member, and a closure member seating against the upper end of said seat member to close said inlet, both said members being movable upwardly with respect to the body and said closure member being movable upwardly with respect to said seat member to open the inlet.

7. In a well-cleaning device, a body having. a low pressure chamber and an inlet therefor, a seat member, means yieldably supporting said member, and a closure member seating against the upper end of said seat member to close said inlet, both said members being movable upwardly with respect to the body and said closure member being movable by fluid pressure upwardly with respect to said seat member to open the inlet.

8. In a well-cleaning device, a body having a low pressure chamber and an inlet therefor, a seat member, means supporting said member, and a. closure member seating against the upper end of said seat member to close said inlet, both said members being movable upwardly with respect to the body and said closure member being movable upwardly with respect to said seat member to open the inlet, said closure memberbeing adapted to seat by gravity to close the inlet.,

9. In a well-cleaning device, a body having a low pressure chamber and an inlet therefor, a valve for said inlet and movable with respect to the body, a valve seat movable with the valve and with respect to the body, releasable means associated with the valve to render well pressure normally effective to hold said seat against the valve; and means operative upon the release of the first mentioned means to render well pressure effective to open the valve.

10. In a well-cleaning device, a bodyhaving a low pressure chamber and an inlet therefor, a valve for the inlet and embodying a seat member and a cooperating closure member, both said members being movable upwardly with respect to the body member under the influence of well pressure, releasable means associated with one of the membersv to hold it against upward movement and thereby rendering well pressure effective to close the valve, and means eifective upon release of the first mentioned means to stop upward movement of the seat member ahead of the valve and thereby render the well pressure eective to open the valve.

11. In a well-cleaning device, a body having a loW pressure chamber and an inlet therefor, a seat member and a closure member cooperating to control fluid flow through the inlet, both said members being upwardly movable with respect to the body under the influence of well pressure directed thereagainst, releasable means connected to the closure member adapted to hold said closure member against such movement, the seat member engaging the closure member when the latter is so held and being thereby releasably limited in its upward movement, and means effective when said closure member is moved upwardly to stop upward movement of said seat member in a position spaced below said closure member in its elevated position.

12. In a well-cleaning device, a body having a low pressure chamber and an inlet therefor, a seat member and a closure member cooperating to control uid-ow through the inlet, both said members being upwardly movable with respect to the body under the iniiuence of well pressure directed thereagainst, releasable means adapted to hold said closure member against such movement, the seat memberv engaging the closure member when the latter is so held and being thereby releasably limited in its upward movement, and means effective when said closure member is moved upwardly to stop upward movement of said seat member in a position spaced below said closure member in its elevated position, said closure member being adapted to seat by gravity to close the inlet.

13. In a well-cleaning device, a body having a low pressure chamber, a seat member embodying a tube having sliding t in a body-bore below and with its bore in communication with the chamber, an upwardly facing annular seat on the tube, releasable means holding the tube against upward movement in the body-bore, a closure above and mounted for vertical movement with respect to the tube, the lower ends of the tube and closure being adapted to be exposed to well-pressure and the tube normally engaging the closure, means for releasing vthe holding means to allow upward movement of the tube and closure under the influence of well pressure, and a stop on the body limiting the extent of upward movement of the tube to less than that of the closure.

14. In a well-cleaning device, a body having a low pressure chamber, a seat member embodying a tube having sliding t in a body-bore below and with its bore in communication with the chamber, a closure in the tube-bore above the tube and mounted for vertical movement with respect thereto, releasable means holding the closure against upward movement in the bodybore, the lower ends of the tube and closure being adapted to be exposed to well-pressure and the upper end of the tube normally engaging the closure, means for releasing the holding means to allow upward movement of the tube and closure under the influence of well-pressure, a stop on the body limiting the extent of upward movement of the tube to less than that of the' 10W-pressure chamber, a seat member 'embodying 75 a tube mounted for vertical movement through a body-bore below the chamber, the tube-bore being in communication with said chamber, an upwardly facing annular seat on the tube, a closure above and mounted for relative vertical movement with respect to the tube to open and close the tube-bore at the seat, means on the body limiting the extent of upward movement of the tube to less than that of the closure, a sleeve mounted on the exterior of the body for limited longitudinal movement, and a pin connected to said closure and extending through angular slots in the body and sleeve, all in a manner whereby relative longitudinal movement of the body and sleeve allows relative longitudinal movement between the body and closure.

16. In a well-cleaning device adapted to be lowered through a well-casing, a body having a low-pressure chamber. a seat member embodying a tube mounted for vertical movement through a body bore below the chamber, the tube bore being in communication with said chamber, an upwardly facing annular seat on the tube, a closure above and mounted for relative vertical movement with respect to the tube to open and close the tube bore at the seat, means on the body limiting the extent of upward movement of the tube to less than that of the closure, a sleeve mounted on the exterior of the body for limited longitudinal movement, a pin connected to the closure and extending through angular slots in the body and sleeve, all in a manner whereby relative longitudinal movement of the body and sleeve allows relative longitudinal movement between the body and closure, and means engageable with the wellcasing to eil'ect such relative longitudinal movement upon withdrawal movement of the body.

17. In a well-cleaning device, a body having an external packer and having a low-pressure chamber and an inlet thereto, there being a bypassage through the body and around the packer, a valve for said inlet, means for opening and closing said valve. and means carried by said valve for controlling the ow of uid through said by-passage.

18. In a well-cleaning device, a body having an external packer and having a low-pressure I chamber and an inlet thereto, there being a bypassage through the body and around the packer, a valve for said inlet, means for opening and closing said valve, and means carried by said valve for controlling the ilow of fluid through said bypassage, the last mentioned means operating to open the by-passage when said valve is closed, and to close the by-passage when the valve is opened.

19. In a well cleaning device, a body having an external packer and having a low-pressure chamber and an inlet thereto, there being a by-passage through the body and around the packer, a valve movable vertically of the body member to and from inlet-closing position, and means carried by said valve in its movement for controlling the ilow of uid through said passage.

20. In a well-cleaning device adapted to be lowered through a well-casing, a body having a low-pressure chamber, an external packer on the body, there being a normally open by-passage in the body around the packer, means actuatable to admit iluid to said chamber to charge it, the charge thereafter being releasably retained in the chamber, and means actuable to close the by-passage while the first mentioned means is actuated to admit the charge to the chamber, both said means being actuated by virtue of withdrawal movement of the body, and the second named means being actuated to give a delayed reopening of the by-passage during subsequent withdrawal movement of the body.

. WELDON C. ERWIN.