US2059630A

US2059630A - Well cleaning device

Info

Publication number: US2059630A
Application number: US3017A
Authority: US
Inventors: Weldon C Erwin
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-01-23
Filing date: 1935-01-23
Publication date: 1936-11-03
Anticipated expiration: 1953-11-03

Description

Nov. 3, 1936. w. c. ERWIN 2,059,630

WELL CLEANING DEVICE v Filed Jan. 23, 1955 5 Sheets-Sheet 1 Z4 /5c455/@MJ 8%. /55 Y 8 59/ lbfarrzey,

Nov. 3, 1936. w. c. ERW|N WELL CLEANING DEVICE Filed Jan. 23, 1955 3 Sheets-Sheet 3 Inventar Wada T/w z'lz.

Patented Nov. 3, 1936 i UNITED STATES PATENT oFFlcE 2,059,630 WELL CLEANING DEVICE Weldon C. Erwin, Huntington Park, Calif., as-y signor to John Grant, Los Angeles, Calif.

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 up such pressure actions or high velocity fluid-movements as to dislodge foreign matter which may be offering obstruction to free passage of fluid through fissures in the formation or perforations in the well casing.

While the invention is here described in connection with a device having a singlecharge lowpressure 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 valvecontrol mechanism may be applied with advantage to the inlet cf any type of low pressure chamber, irrespective of the manner in which the charged chamber is subsequentlyemptied 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 fluid 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 fluid charge. vThe 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.

Conditions under which it is desirable or neccssary to perform well cleaning operations are so well known to workers in the art that it will be unnecessary here to detail them. However, it is well recognized that cleaning devices of the general nature set forth above must have certain characteristics, not easy of attainment, in order that they may. be capable of performing efficiently and surely the services required. For instance, it is highly important that the inlet to the low pressure chamber -be kept tightly closed until the cleaner has reached the predetermined zone of operation and yet, in spite of that tight closure and in spite of the usually high fluid pressure in that zone, the vinlet must be capable of practically instantaneous full-opening, under the control of the operator, after reaching that zone. Further, 'the vcontrol mechanism must not only be sure and fast in operation, but, to be fully efcient, must be .of a nature which does not interfere with the rapid lowering or raising of the device to and from the zone of operation. Further, it must present little or no danger of accidental valve-tripping.

Therefore it is among the general objects of the invention to provide a cleaner which shall have the above desirable features, as well as others which may'be pointed out to better advantage in connection with the detailed description to follow.

It may here be pointed out, however, that the present invention relates to cleaners wherein the inlet valve is substantially balanced, that is, two oppositely disposed faces associated with the valveare exposed to well pressure, the pressure on the upwardly facing exposed pressure area (here specifically shown as on a piston depending from the valve) having the effect of substantially balancing the well pressure which is otherwise effective in a valve-closing direction, it following that the effect of well pressure may be more or less disregarded in effecting unseating of the valve when the zone of operation is'reached, even though that pressure be relatively high.

Preferably, however, though this is not essential to the invention considered in its broader aspects, there is a slight differential in the valve and piston areas exposed to well pressure, this differential being such that the well pressure has a. slight preponderance of valve-closing effect, whereby the well-pressure is utilized to a reduced or limited extent (well within the power of the valve-unseating means) to maintain proper closure of the inlet/ as the device is lowered to position. Preferably, also, a spring is employed in `connection with the valve, dependence being had well pressure becomes effective in a valve-opening direction and, in the event the well pressure is of sucient value, such pressure .is actually effective further to open the valve.

The claims of the present application are drawn to valve-balancing and valve-actuating features, as well as certain relationships between the by-pass and valve-balance-chamber.

Fig. 1 is an elevation of my improved cleaner;

Fig. 2 is an enlarged fragmentary section on line 2-2 of Fig; l1, but additionally indicating the device as being-within a perforated casing;

Fig. I3 is an enlarged section on line 3-3 of Fig. 1, and likewise showing a surrounding caslng;

Fig. 4 is an enlarged fragmentary section of that portion of the device lying immediately above the portion indicated in Fig. 3 but repeating the showing of the valve proper of Fig. 3.

This view likewise includes a showing of 'surrounding casing;

Fig. 5 is a section on line 5-5 of Fig. 3;

Fig. 6 is a section on line 6-6 of Fig. 3;

Fig. 'l' is a section on line 1-1 of Fig. 2;

Fig. 8 is a fragmentary section, partially in elevation, showing the by-pass arrangement of the device;

Figs. 9 and 10 are similar to Figs. 2 and 3, respectively, but showing the parts in dilferent positions. j

As has been 'previously stated, my cleaning device is particularly well adapted, but not limited, to the dislodgment of foreign matterfrom the perforations of well-casing, and therefore I have illustrated the device in Figures 2 to 10 as positioned within such a perforated casing or screen A 'having any suitable type of perforation, here conventionally indicated at B.

The body member C of the cleaning device is here shown as made up of a pluralityA 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.

Threadably connected body or casing sections are indicated at I0, II, I2 and I3, sectionIO (Fig. 4) serving as a head or top closure for the charge-receiving or low-pressure chamber D which is annularly defined by those sections. Attachment section I4 is threadably connected to section I and serves as means whereby the body member may be attached to a suspension element-cable I5, for instance. Section II, here shown as longitudinally contracted, may be of any desired length, or, itself, may be sectional. A forty foot length gives chamber D a capacity ample for most operations. Head section I0 has a reduced, axial bore I6 from which extends a transverse passageway I'l controlled by a springclosed, outwardly-opening relief valve generally indicated at I8. The function of this valve is merely to relieve high pressure in the charge chamber as the tool is raised into zones of lower pressure. To facilitate unloadingv vof chamber D, as will hereinafter be described, I preferably provide an inwardly opening and spring-closed dump-relief valve generally indicated at I9. 'I'his valve is fully described and claimed in the copending application of W. C. Erwin, et al. on Well bailers, filed April 22, 1933, Ser. No. 667,439

wherein the valve showing is substantially iden-- tical 'with the instant showing.` It will sufce here to state that removable screw-plug 20 normally closes passageway 2|. When chamber D is to be unloaded, plug 20 is removed andpassageway 2l is then adapted to put that chamber into communication with the atmosphere when the negative pressure therein (as created by dumping of the fluid) is of a value allowing the springclosed valve I9 to open under atmospheric pressure.

Section I2 is provided with a removable dumpdoor 22, the construction and mounting of which are fully described in said copending application Ser. No. 667,439, in which application the showing of the door is substantially the same as the instant showing and which application contains claims to these features. The door is opened by loosening screws 23 (which normally press the door inwardly to compress gasket 24 and thus provide a fluid-tight seal), and then sliding the door transversely to clear lugs 25 from lips 26, which latter dene way 2l (Figs. l and 4).

Section I2 is also provided with an upwardly opening check valve 28, transverse rod 29 being spaced thereabove to serve as a stop for valveball 30.

The main inlet valve for chamber D is provided in section I3 and is generally indicated at 3I,

numerals

32, 33 indicating theseat member and ball or stopper member, respectively. 'I'he inlet opening to the chamber, normally closed by stopper 33, is indicated at 34, being particularly identified in view of the fact that its crosssectional area is a matter of significance in connection with the balance of the valve, as will appear. Of course, the stopper may be of any suitable configuration and therefore its illustrated spherical form is in no Way to be considered as limitative.

Integral with and extending `downwardly from stopper 33 is a stem generally indicated at 35 and made up of sections 36 and 3l threadably connected at 38, cross head or abutment 39 being rigidly clamped between -opposed shoulders 40 and 4I of sections 36 and 3l, respectively. Se-

cured to the lower end ofl section 3l, as by nut 42, is a piston 43 which may be of any suitable type, though here shown as made up of oppositely opening cup-

leathers

44 and 45 at opposite sides of spacer 46, nrt 42 serving to clamp the spacer and'cup assembly against stem-shoul' der 41.

Piston 43 is mounted for reciprocation in cylinder 48 which is open at its upper end 50 and closed at its lower end I, a valve-closing spring 52 being disposed in closed, atmospheric-pressure-chamber 53 vertically defined by the piston and end 5I. As will appear, the under face of stopper 33 and the upper end of piston 43 are exposed to well pressure, and when the stopper is member C. It is also utilized to provide a duct 55 for directing well-fluid from certain chosen zones to inlet valve 3| and to support a packer or barrier 56 utilized in connection with certain cleaning operations, a pilot nose 51 and a centering guide 58, but the fact that the drawings illustrate the cylinder-supporting means as utilized for performing the additional functions is not to be considered as limitative on its broader inventive aspects, considering it as a cylindersupport which need not have these additional functions to render it fully operative as such a support.

Barrel 54 is made up of an outer tubular section 59 which is threaded into body section I3 below valve 3| at 60, and an inner tubular section 6| whose top and bottom terminate short of the ends of section 59, sections 59 and 6| being secured rigidly together by screws 62 (Figs. 3 and 5). Lateral ports 63 extend through the sections to put well-fluid into communication with duct 55 which comprises the bore of section 6|.A

Space 64, between valve 3| and the upper .end of section 6| may be considered a part or continuation of duct 55 or as a valve chamber.

Cylinder 48 is fitted within the lower end of section 59, being held in position by tubular nose 51 which is threadably connected to the section and holds the upwardly-facing cylinder shoulder 65 tightly engaged with the lowerA end of the section.

Stern 35 extends axially and with annular clearance through duct 55 and preferably, though not necessarily, through a stuffing box 66 provided at the lower end of section 6|, the stufling box closing off the duct 55 from chamber 61 defined by section 6| above cylinder 48. Lateral ports 68 open through guide 58 and section 59 to put chamber 61 and hence the upper end of cylinder 48 in communication with well-fluid, both for the valve-balancing effect and for by-passing uid, as will hereinafter be made apparent.

Guide 58 consists of a tubular body member 69 having angularly spaced and longitudinally extending guide ribs 10, preferably having oppositely tapering ends, the member being clamped between section-shoulder 1| and nut 12.

Cross-head 39 is adapted to play longitudinally of the body through diametrically opposite slots 13 in sections 59 and 6|, the ends of the cross head extending outwardly beyond section 59. Upwardly facing shoulders 14 serve to limit the downward movement of said cross-head and hence of the valve stem and valve with respect to the body member. Vertical clearance is left between the cross-head and the upper ends o f the slots, when in the valve-closed position of Figs. 2 and 3, to insure that the cross-head will not interfere with full valve-closure, even after reasonable wear of the valve parts. Preferably, I provide in chamber 64 a centering spider 15 for stem 35 and stopper 33, said spider here being preferably shown as fixed to thestem and sliding with relation to sectionl 59.

Coacting with cross-head 39 to provide a valveopening or actuating device, is a shoe 16 mounted for limited longitudinal sliding movement on barrel 54. While ths shoe may be of any suitable design, it is here shown as made up of a pair of spaced rings 11 to which are attached the opposite ends of outwardly bowed leaf-springs 18, or the like, serving as gripping members adapted frictionally to engage well casing A. As the cleaner is lowered through the well casing, these gripping'members retard the shoe so the barrel the shoe is spaced above cross heads 39.

ever, this spacing, though preferable, is not essential to the operation ofthe device, it only-being necessary that the shoe does not bear against the cross-head in a manner to holdthe valve open during descent of the tool.

As mentioned above, in certain cleaning operations it is desirable to use packer 56 at a point above lateral ports 63, thus isolating these ports from the well iiuid within casing A above the packer and more or less localizing the effectof fluid4 movement (as created by the sudden charging of chamber D) at the casing perforations adjacent said lateral ports. Where the casing perforations are exceedingly tightly plugged it may sometimes be desirable to localize more definitely such effect by providing a packer in place of guide 58, the two packers then serving to deiine ends of a zone isolated both top and bottom from the main iiuid column within the casing. However, such provision is not essential lto ordinary operation and therefore the showing is not complicated by such an addition, it being evident that the certain features of the invention are applicable with equal advantage irrespective of packer particularities.

While packer 56 may be of any suitable character and does not necessarily have to make'a seal but only a fairly close constriction, it is here shown as a type well known in the art, being made up of a collar 19, shouldered at on section 59, an upwardly opening and radially expansive rubber or composition cup 8|, and a sleeve 82 adapted t0 thrust the'cup-bottom against collar 80. Nut 83 is threaded on section 59 and serves to clamp the elements of the packerassembly in iixed positions on the section. Spring reinforcing wires 84 may be provided for the packer rubber.

The packer lls the annular space between the barrel 'and well-casing A and when the packer is moved upwardly thel fluid column thereabove tends to expand it radially into tight frictional contact with the well casing. In lowering or raising the cleaner it is therefore desirable to by-pass the well-fluid around the packer, for obvious reasons. It is further desirable that the by-pass extend to a point below the zone of immediate operation, that is, around the zone into which lateral ports 63 open so, when chamber D is suddenly opened to duct 55, well iiuid from above the packer may not have access to that duct through the by-pass, which would otherwise have the result of minimizing the localizing effect.

The by-passage is formed in the following manner. Section 6| has a reduced-diameter portion 85 (Figs. 3 and 6) which, with section 59, defines an annular chamber 86 closed at its upper end 'by annular shoulder 81. Lateral ports 88 extend through sections 59-6I from this chamber to the exterior of the barrel at a point, in effect, above packer 56. Below chamber 86 and extending to chamber 61, the diametrically opposite sides of section 6| are milled away flush with the outside diameter of reduced portion 8-5 to provide longitudinal passageways 89 (Figs. 6, 'l and 8). In raising or lowering the cleaner, uid is by-passed in one direction or the other around the packer and the charge-intake-extent of barrel 65 through the following path, which may be termed a bypass duct, ports 68, chamber 61,passageways 89.

chamber 86 and ports 88. Stuffing box 66 serves to prevent direct communication between ports 68 and intake duct 55 so, upon the charging of chamber D, well-fluid may not be drawn in through the by-pass ports and thus minimize the localization of the cleaning effect, though when such localization is not essential (as is true in certain cleaning operations) chamber 61 and ports 68 may as well be in communication withl duct 55.

I will now describe a typical operation of the tool, noting in the course ofthe discussion certain pressural effects gained by virtue of chosen relative pressure areas.

The tool is lowered with the parts in the positions of Figs. 1, 2, 3 and 4, it following that chambers D and 53 contain air at atmospheric pressure, spring 52 acting through the piston and stem 35 to hold valve 3| closed. It Will rst be assumed that the diameters of inlet openings 34 and of piston 43 are substantially equal, it following that there is an atmospheric balance at the upper side of the valve stopper and the lower end of the piston, and the effective pressure-taking areas presented by the under face of the stopper and the upper facel of the piston are substantially equal and therefore under well-pressure balance. The eiective areas presented by the under face of the stopper and the upper face of the piston are equal to the cross-sectional area of inlet 34 (or the bore of cylinder 48) minus the .cross-sectional area of stem 35.

as the device is lowered through the well-fluid, the pressure of that iluid is eiective equally in a valve opening and closing direction, it following that the valve is-substantially balanced, as far as fluid pressure directed thereagainst is concerned, and the stopper is held to seat under the constant pressure ofl spring 52. The power of that spring and the resistance to valve-opening movement oiered by the air body in chamber 53 may be readily overcome by the valve opening means whose operation is now to be described.

When the predetermined zone of operation is reached, the driller checks the descent of the tool and then imparts limited withdrawal movement thereto by reeling-in cable I5. Body member C and extension 54 are thus lifted, while the frictional engagement of members 'i8 with casing A holds shoe 16 stationary, the lower ring v`|`| thereof forming a stop with which cross-head 39 contacts whereby further upward movement of the body member moves seat 32 away from stopper 33 (Figs. 9 and 10) This relative movement4 opens valve 3| to allow a sudden inrush of welluid, under relatively high pressure, into chamber D, its path being through inlet 63, duct 55, chamber 64 and inlet 34. The inrushing uid carries with it foreign matter (which is to be bailed) into the chamber, and where the device is used as a perforation cleaner, the inrush sets up such movement in the well fluid surrounding the tool below the packer as to dislodge slugs of foreign matter in casing perforations B. The slugs (which sometimes are broken up by the fluid action and sometimes are removed intact) usually, though not necessarily are carried into chamber D along with the inrushing fluid.

Since valve 3| is substantially balanced, the force necessary to open that valve is only such as will compress spring 52 and the air in chamber 53, and it is well within the capacity of the actuating mechanism to exert such force. Furthermore, since the pressures on top the stopper and beneath the piston 43 are initially equalized, the

Consequently,

extent of air-compression necessary to crackl the valve is negligible. Additionally, the instant the valve is cracked, the pressure of the well fluid on top the stopper has a preponderant valve opening effect (aiding in the further compression of the spring and air in chamber 53) due to the .additional effective exposure to well pressure of -of the entire upper end of the stopper to welluid after the valvehas been cracked, the effective wellpressure may be of such value as actually to force the valve to full open position against the pressure of spring 52 and of the air in chamber 53. It follows-that the arrangement illustrated and so far-described is one in which the well pressure is substantially ineffective either to resist or to cause initial valve opening movement but, once the valve has been started open by the mechanically operated actuator, the well lpressure becomes effective further to open or aid in the opening of the valve, a feature which, so far asl am aware, is entirely new in connection with piston-balanced valves. It will be understood, of course, that dependence need not be -had on this fluid-pressure effect to move the l'valve to full open position, for a continued upward pull on cable I5 acts through the cross head to open the valve fully and positively.

Now it is contemplated by my invention, and, in fact, it may be considered as my preference, that the effective cross-sectional area of inlet 34 may be slightly greater than that of piston 43 so, when valve 3| is closed, the valve-closing effect of the well pressure is slightly preponderant. I have not separately illustrated this situation, as` it would be represented merely by a dimensional change of slight degree, and this is .readily understandable without specific illustration. I have chosen to describel the situation of full-balance first .merely because it lends itselfbetter to initial description.

Where such a diiferential in pressure-taking areas is provided, spring 52 need be depended upon only to hold the valve closed until the well pressure, acting upon the larger effective pressure-taking face, is suiiicient to hold the valve `seated. This arrangement has an advantagev in that as the cleaner is lowered-to zones of increased well-pressure, whereby the likelihood of leakage through valve 3| into chamber D is increased, that-well pressure is correspondingly increasingly effective to hold. the valve to'seat and thus prevent such leakage. However, in spite of this differential, when the valve is cracked" by withdrawal movement of cable l5, the exposure of the top of the valve stopper to well pressure will give said pressure an advantage in `a valveopening direction just as described in connectionv with the fully balanced valve.

Check valve 30 opens, of course, during the inrush -of fluid to chamber D, and thereafter closes to form a foot-valve to hold the charge. As the cleaner is subsequently raised, there arises a differential in the internal and external pressuresv imposed on the cleaner body, but relief valve I8 allows a bleeding of chamber D to reduce the well, door 22 is opened to unload chamber D, such built-upinternal pressure as remains in the chamber and generally as measured by the strengthof the relief valve spring, giving the material an initial outward impulse. To prevent a substantial negative pressure from de-v veloping in the chamber, which would otherwise prevent complete unloading, Plug 20 may be relmoved to permit inflow of air through valve I9 'to the top of the chamber.

As distinguished from arrangements wherein a balancing piston is provided above the inlet valve, it is to be noted that here the valve and all parts associated therewith in no way complicate or obstruct the low pressure chamber or inlet thereto and are easily accessible for inspection or replacement without disturbing the charge-receiving barrel, which, since it is to be leak-proof, should be disassembled as infrequently as possible. Furthermore, the specified relative arrangement not only renders it possible to gain the fluid-pressure, valve-opening eiect described above, but it also prevents leakage from the balancing cylinder past the pistonin to thechargereceiving chamber.

Preferably, I provide shoe 51 and cylinder 5| with bleedport 51a, normally closed by plug 51h. In the event iluid leaks into chamber 53, the chamber may be emptied by removing plug 51h.

While I have illustrated and described-specific embodiments of the invention, it will be under'- stood such illustration and description are mere- 'ly illustrative of andv not limitative on said 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 member having a low-pressure chamber -and an inlet opening therefor, a downwardly opening valve for the inlet, s'aid valve having a pressure-takingface adapted to be exposed to fluid within the well, a stem depending from the valve, a. piston on said stem and having a pressure-taking-face in effective opposition to said valve face, an abutment on the stem between the valve and piston, and an actuating member movably mounted on the body member and engageable with the abutand an actuating member movably mounted onV the body member and engageable with the casing and' abutment.

3. In a well cleaning device, a casing having a low-pressure chamber and an inlet opening therefor, a valve for the inlet, said valve having a pressure-taking-face adapted to be exposed to fluid within the well, a piston connected to the yvalve for movement therewith and positioned therebelow, said piston having a pressure-takingface disposed in eiective opposition to said valve face and adapted to be exposed to fluid within the well, and a spring below the valve and operatively associated therewith to urge it towards closed position.

4. In a well cleaningA device, a body member having a low-pressure chamber and an inlet opening therefor, a downwardly opening valve for the inlet, said valve having a pressure-takingface adapted to be exposed to fluid within the well, a cylinder closed at its lower end and open at its upper end to the fluid in the well, means supporting said cylinder below said valve,a piston in the cylinder, and a stem connecting said valve and piston.

5. In a well cleaning device, a body member having a low-pressure chamberl and an inlet opening therefor, a downwardly opening valve for the inlet, said valve having a pressure-takingfaceadapted to be exposed to fluid within the well, a cylinder closed at its lower end and open at its upper end to the fluid in the well, means supporting said cylinder below said valve, a piston in the cylinder, a stem connecting said valve and piston, and a spring in the cylinder below the piston and adapted to urge said piston, stem and valve upwardly.

6. In a well cleaning device, a body member having a low-pressure chamber and an inlet opening therefor, a downwardly opening valve for the inlet, said valve having a pressure-takingface adapted to be exposed to iluid within the well, a cylinder closed at its lower end and open at its upper end to the fluid in the well, means supporting said cylinder below said valve, a piston in the cylinder, a stem connecting said valve and piston, an abutment on said stem, and a lwell, a cylinder closed at its lower end and open4 at its upper end to the fluid in the well, tubular means extending from the body member and supporting said cylinder below said valve, a piston in the cylinder, and a stem connecting said valve and piston, the bore of said supporting means forming an inlet duct to said inlet opening.

8. In a well cleaning device, a body member having a' low-pressure chamber and an inlet opening therefor, a downwardlyopening valve for the inlet, said valve having a pressure-takingface adapted to be exposed to fluid within the well, a cylinder closed at its lower end and open at its upper end to the fluid in the well, tubular means extending from the body member and supporting said cylinder below said valve, a piston in the cylinder, a stern connecting said valve and piston, the bore of said supporting means forming an inlet duct to said inlet opening, and a packer on said supporting member, there being a by-pass comprising a pair of openings, through said supporting member, one above and one below the packer and a passageway extending longitudinally of the supporting member and connecting said openings. f

9. In a well cleaning device, a body member having a low-pressure chamber and an inlet opening thereior, a downwardly opening valve for the inlet, said valve having a pressure-takingface adapted to be exposed to uid within the well, a cylinder closed at its lower end and open at its upper end to the iluid in the well, tubular means extending from the body member and supporting said cylinder below said valve, a piston inthe cylinder, a stem connecting said valve and piston, the bore of-said supporting means forming an inlet duct to said inlet opening, and a packer on said supporting means, there being transverse inlet ports in said supporting member opening to said duct below the packer, and there being a bypass comprising a pair of openings through said supporting member, one above the packer and the other below the lowermost lateral port, and a passageway extending longitudinally of the ,X supporting member and connecting said openings.

10. In a well cleaning device, a body member having a low-pressure chamber and an inlet opening therefor, a downwardly opening valve for the inlet, said valve having a pressure-takingface adapted to be exposed to iiuid within the well, a cylinder closed at its lowerv end and open at its upper lend to the fluid in the well, tubularA means extending from the body member and supporting said cylinder below said valve, a pistonin the cylinder, a' stem connecting said valve and piston, the bore of said supporting means forming an inlet duct to said inlet opening, and a port, and a passageway extending longitudinally of the supporting member and connecting said openings, the communication of the upper end of said cylinder with the well fluid being by way of a portion of said by-pass.

11. In a well cleaning device, a casing having a low-pressure chamber and an inlet opening therefor, a valve for the4 inlet, said valve having a pressure-taking-face adapted to be exposed to fluid within the well, a piston connected to the valve for movement therewith and positioned therebelow, said piston having a pressure-takingface disposed in effective opposition to said v'alve face and adapted to be exposed to fluid within the well, and a foot-valve in the chamber above the inlet valve.

12. In a well cleaner, a casing having a lowpressure chamber and an inlet opening therefor, a valve for said inlet opening and having a pressure-taking-face adapted to be exposed to :duid in the well, said casing having a second low-pressure chamber out of communication with the first chamber, and, a piston .connected to thev valve for movement therewith and having one end face adapted to be exposed to fluid in the well and having its other end face exposed in said second chamber.

13. In a well cleaner, a casing having a lowpressure chamber and an inlet opening therefor, a valve for said inlet opening and embodying a seat member and a cooperating stopper member, one of said members having` a pressure-takingface adapted to be exposed to fluid in the well,

said casing having a second low-pressure chamber out of communication with the rst chamber, and a piston connected to said one member for movement therewith and having one end adapted to be exposed to uid in the well and having its other end exposed in said second chamber.

14. In a well cleaner, a casing having a lowpressure chamber and an inlet opening therefor, a valve for said inlet opening'and embodying a seat member and a cooperating stopper member,

said stopper having a pressure-talring-face` pressure chamber and an inlet opening therefor,

a valve for said inlet opening and having a pressure-taking-face adapted to be exposed to iluld in the well, said casing having a second lowpressure chamber out of communication with the first chamber, a piston connected to the valve for movement therewith and having one end face adapted to be exposed to fluid in the well and having its other end face exposed in said second chamber, and a spring in said 'second chamber adapted to urge the piston and valve in a valveclosing direction.

16. In a. well cleaner, a casing having a lowpressure chamber and an inlet opening therefor, a valve for said inlet opening and having a pressure-taking-face adaptedto be exposed to fluid in the well, said casing having a second lowpressure chamber out of communication with the rst chamber, a piston connected to the valve for .movement therewith and having one end face adapted to be exposed to fluid in the well and having its other end face exposed in said second chamber, and a spring adapted to urge the valve in a closing direction.

17. In a well cleaner, a casing having a lowpressure chamber and an inlet opening therefor, a valve for said opening and having a given pressure-taking face adapted to be exposed to fluid in the well when the'valve is closed, and a balancing piston connected to the valve for movement therewith and having a pressure-taking face adapted to be exposed to fluid in the well, said valve having another face exposed,4at least in part, to the low pressure chamber when the valve is closed and adapted to be exposed to fluid in the well when the valve is open, said last named face being of greater. effective area when the valve is open than is the given face.

18. In a. well cleaner,l a casing having a lowpressure chamber and an inlet opening therefor, a valve for said inlet opening and having a pressure-taking-face adapted to be exposed to fluid in the well, said casing having a second lowpressure chamber out of communication with the rst chamber, and a pistonconnected to the valve for movement therewith and having one end face adapted tobe exposed to fluid in the well and having its other end face exposed in said second chamber, there being a differential in the areas ofy the faces exposed to the ud in the well whereby said fluid is effective', when the valve is closed, in a valve-closing direction.

19. In a well cleaning device, a body member having a low-pressure chamber and an inlet opening therefor, a downwardly opening valve for the inlet, said valve having a downwardlyl facing pressure-taking-face adapted to be exposed to fluid within the well, a stem depending from the valve, a piston on said stem and having an upwardly facing pressure-taking-face in eiec- .tive opposition to said valve face, an abutment on the stem between the valve and piston, and an actuating member movably mounted on the body member and engageable with the abutment.

aeeeeo W 20. In a well cleaner, a casing having a lowpressure chamber and an inlet opening therefor, a downwardly opening valve for said inlet and having an upwardly facing area exposed within the chamber and a downwardly facing area adapted to be exposed to uid in the well, said casing having a second. low-pressure chamber out of communication with the rst chamber, and a piston connected to the valve for movement therewith and having an upwardly facing area exposed to fluid in the Well and a downwardly facing area exposed in said second 5 chamber.

WELDON C. ERWIN.