US 3472171 A
Abstract available in
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Description (OCR text may contain errors)
Oct. 14, 1969 H. J. sADLl-:R
CYLINDER sLEEvE ASSEMBLY EOE PIsToN-TYPE PUMP Filed oct. 24, 1967 United States Patent O Uliio Filed Oct. 24, 1967, Ser. No. 677,600 lint. Ci. Fildb 1/00; F163 11 /04 US. Cl. 163-171 2 Claims ABSTRACT F THE DISCLOSURE An improved cylinder sleeve assembly for piston-type pumps utilizing a reciprocating positive displacement piston operating within the contines of a replaceable cylindrical sleeve, the sleeve being designed to be retained within a bore in the pump body by means of a surface portion of a cylinder head member engaging a terminal edge of the cylinder sleeve assembly. The sleeve assembly is provided with a main body member having externally arranged shoulders for controlling the axial disposition within the body bore, the portion of the main body near the terminal end having a relieved zone for receiving a clamping ring and maintaining a compressible O ring in captive abutting relationship with the inner edge of the clamping ring and the upper shoulder of the sleeve. The cylinder head exerts a force against the clamping ring which in turn expands the O ring outwardly into contact with the internal surface of the bore, thus forming an effective seal between the sleeve and the pump body without requiring close tolerance levels in the components.
This invention relates to pumps and more particularly to a pump of the piston type with positive displacement and utilizing one or more reciprocating pistons to perform the pumping operation. This invention is an improvement over that invention disclosed and claimed in U.S. Patent 3,238,890, which patent is assigned to the same assignee as is the present application.
In the manufacture of piston pumps, it is normally deemed desirable to employ a cylindrical 'sleeve for con lining the reciprocating piston. Since the `sleeve is normally exposed to high working pressures, and exposure to fluids which may adversely affect the material of construction, means are preferably provided for ease of servicing of the cylinder sleeve assembly. In addition, it is imperative that proper sealing be available between the cylinder sleeve assembly and the Surfaces within which the sleeve is received.
It is a primary object of the present invention to provide a pump which is economical in construction, and which may be serviced with minimal difficulty.
It is yet a further object of the present invention to provide an improved pump assembly which contains a removable cylindrical pumping sleeve assembly, the sleeve assembly being provided with improved seals to effectively isolate the pumping chambers from the mechanical mechanisms of the pump.
It is yet a further object of the present invention to provide an improved cylindrical sleeve assembly for a reciprocating piston type pump with positive displacement, wherein the cylindrical sleeve assembly is designed to be received within the pump structure in an effective manner, without requiring unusual or close tolerance levels.
It is still a further object of the present invention to provide a double-acting piston pump assembly in which the body cylinders are symmetrically disposed and contain identical and interchangeable parts to minimize the cost of construction and replacement.
These and other objects and advantages of this invention more fully appear in the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views and in which:
FIGURE l is a vertical sectional view of a pump structure utilizing the concept of the present invention, and .being taken along the line and in the direction of the arrows 1 1 of FIGURE 2;
FIGURE 2 is a vertical section taken along the line and in the direction of the arrows 2 2 of FIGURE l, with certain of the components being shown in full-line representation; and
FIGURE 3 is a detail view of the cylinder sleeve assembly utilized in the structure shown in FIGURES 1 and 2.
In accordance with the preferred modification of the present invention, the pump assembly shown in FIG- URES 1 and 2 includes a structure generally designated 10 comprising a housing 11, a housing head 12, and a housing foot 13. The housing 10 is in the form of a hollow closed loop shown in FIGURES l and 2, a continuous passageway 14 being formed throughout. Inwardly from housing 10 is a medial open space 15 as shown in FIGURE 1 which space is preferably open to the atmosphere.
The housing body 11 has a cylindrical bore 16 formed transversely of the closed loop housing and extending upwardly through the top 17 of housing body 11 and downwardly through bottom 18 thereof. In the form Shown in the instant application, the cylinder bore has a single vertical axis which passes through the center of the medial open space 15 within the closed loop housing. Cylindrical bore 16 thus communicates between the endless passageway 14 and the atmospheric air in space 15.
That portion of the endless passageway which lies within the housing body 11 constitutes a pair of passageways 19 and 20 to the right and the left respectively of the medial open space 15 shown in FIGURE l. Each of the upstanding passageways 19 and 20 terminates at top 17 and bottom 18 in an enlarged shouldered opening 21 as shown in FIGURE l. The housing body 11 is also provided with a threaded inlet 22 and a threaded outlet 23 communicating respectively with the passageway portions 1'9 and 20 of the endless passageway 14.
Referring now to FIGURE 2, a large boss 24 is cast integrally with the body 11 and is provided with an opening 25 adapted to receive a roller bearing structure 26. A cap or cover 27 is removably secured to the housing body 11 to cover the atmospheric opening 15 when the pump is assembled.
Also constituting a part of the closed loop housing 10 is the housing head 12 which may be bolted thereon by means of cap screws 28 as shown in FIGURES 1 and 2.
An endless groove 29 may be cast in face 30 and provided with a continuous sealing gasket 31 as shown. It will be observed that a portion 32 of the surface 30 extends marginally over the passageway openings 21 for a purpose to be subsequently disclosed. A contoured recess 33 is formed in the housing head 12 so as to complete the endless passageway 14 and provide communication between passageways 19, 20, and cylinder bore 16.
The housing food 13 is similarly bolted to the housing body 11 by such means as cap screws 28 and the foot 13 is similar in construction to housing head 12 with the eX- ception of the legs 34 which may be utilized to support the entire pump if desired. The housing foot 13 is provided with a marginally projecting surface 32, a contoured recess 33, groove 29, sealing gasket 31 and surface 30 for sealing against the opposed surface 18 of housing body 11, all as previously described in connection with the housing head 12.
At the upper and lower ends 17 and 18 respectively of housing body 11 and within the traversing cylinder bore 16 are positioned a pair of cylinder sleeves, these being in the form of sleeve assemblies generally designated 35. The bodies 36 have shouldered abutment at 39 with the bore 16 so that the outer terminal edge 40 lies generally flush or slightly recessed with the plane of housing body top 17 and bottom 18 as shown. The axial dimension of the ring 37 is such that significant compression of the O ring 38 will occur when the ring 37 is forced into place, and clampingly held by the appropriate head member 12 or 13. Thus, the tolerance levels are not diicult since the ring 37 must merely be sufficiently long in its axial dimension so as to cause deformation and accordingly expansion of the O ring 38 into contact with the bore in the housing body 11. Correspondingly, the axial distance from the terminal edge 40 to the shoulder 40a is not critical, it 'being su'icient that the distance will provide for expansion of the O ring 38 into contact with the wall of the body portion. Sleeve 35 may be provided with skirt extensions which project slightly into the atmospheric space as shown in FIGURE l.
A piston assembly 41 has a connecting rod 42 and a piston 43 disposed at each end thereof as shown in FIG- URES 1 and 2. Where the cylinder sleeves 35 are diametrically opposed as in the instant structure, a single connecting rod 42 may be employed as shown in FIG- URE 2. Further, the rod 42 may be made of shaft material and formed with pins 44 at each end thereof. A piston backing plate 45 is positioned at each end of the connecting rod 42 upon the pins 44 and a piston cup 46 is in turn positioned upon the backing plate. A piston cup spreader 47 is then placed over the piston cup 46 and the spreader 47 is provided with a circumferential groove and O ring cup spreader 48 as shown. A piston cap screw 49 extends axially through the piston assembly and is threadably received in the end of the connecting rod 42 so as to hold each of the piston assemblies in secured relation with respect to the rod. One assembly which has been found to be extremely useful in connection with this structure is that certain assembly disclosed and claimed in U.S. Patent 3,092,427, which patent is assigned to the assignee of the present invention.
A notched area 50 which is substantially in the form of a longitudinal cylindrical segment is cut out of the connecting rod 42 as shown in FIGURE 1 so as to create a flattened surface 51 formed at the side of the connecting rod and a pair of longitudinally spaced bearing surfaces 52 extending laterally outward from the flattened surface 51. The notched out portion 50 of course leaves a substantial connecting portion 53 so that the connecting rod 42 will not be unduly weakened by the presence of the notch.
In order to drive the piston assembly in reciprocation within the cylinder bore, a drive assembly 54 is provided. The drive constitutes a shaft 55 journaled in bearing 26 as shown in FIGURE 2 and the shaft may be provided with a coupling extension 56 as shown. Shaft 55 may be keyed with respect to bearing by such means as snap rings 57. If desired, a pair of spaced bearings may be utilized in order to reduce the radial thrust which may be set up between the coupling extension 56 and the crank, the crank arrangement being discussed hereinbelow.
Eccentrically located with respect to the inner end 58 of shaft 55 is a crank pin 59 as shown in FIGURE 2. The crank pin 59 has a roller 60 rotatably mounted thereon and needle bearings 61 may be suitably interposed between pin 59 and roller 60 as shown in FIGURE 1. Roller 60 is adapted to intert in the notch 50 with its outer circumference engaging the lateral bearing surfaces 52 as shown in FIGURE 2. The circumference of roller 60 may be convexed slightly in axial cross-section so that it will be self-aligning with respect to the bearing surfaces 52 on the connecting portion 53.
The flattened surface 51 lightly contacts or is closely positioned to the exposed end face 62 of roller 60 so that the flattened portion 51 will be keyed thereagainst and the connecting portion 53 prevented from rotating. The opposed bearing surfaces 52 will thus be kept in contact with the roller- 60 at all times during operation of the pump.
Duplicate valve assemblies 63 are positioned in the open ends of each of the upstanding passageways 19 and 20 formed in the housing body 11. The valve assemblies 63 are retained against shoulder 21 so that their outermost ends 64 will lie flush with the respective surfaces 17 and 18 at the top and bottom of housing body 11. The valve assemblies 63 are thus retained in position by the overhanging margins 32 of the housing head and foot portions 12 and 13. Similarly, the head and foot margins 32 bear against the outermost ends 37 of sleeves 35 and retain them in the ends of cylinder bore 16. As indicated, the sleeve assemblies 35 comprise a body portion 36 and a clamping ring 37, and are provided with an O ring sealing element as at 38. Clamping pressure forces the clamping ring against the sleeve and thereby the O ring is expanded outwardly against the surface of the bore 16, for example. The valve assemblies 63 are shown in detail in U.S. Patent 3,238,890.
In the assembly of the pump, body housing 11 first is provided with the bearing 26 and drive assembly 54, the eccentric crank pin and roller bearing being secured to the inner end of the shaft 55 as shown in FIGURE 1. The piston assembly 41 is then placed in position with the pistons 43 lying in the cylindrical bore 16 and the notchedout portion 50 of connecting portion 53 interftting over the roller 60, as shown in FIGURES l and 2. The cylinder sleeves 35 with their O rings 38 and sealing rings 37 attached thereto are then inserted into the cylinder bore 16 at each end, the sleeves serving to abut and hold the bearing assembly 26 in place within the boss 24. Poppet valve assemblies 63 are then inserted into the opened shouldered ends of passageways 19 and 20, the poppet valves in passage 19 permitting llow outwardly thereof by checking the return flow therethrough. The valve assemblies 63 which are inserted into the ends of passageway 20 are inverted so as to permit flow of fluid into the ends thereof but to check the ilow reversely outward. The housing head 12 and foot 13 are then provided with sealing rings 31 vand fastened securely by means of cap screws 28 to the housing body 11 so as to abut and retain the valve assemblies and cylinder sleeves in firmly seated relation. -It will be observed that cap screws 28, once removed, will permit disassembly of the pump, including the sleeve assemblies 35.
In the operation of the pump, fluid enters the inlet 22 and when shaft 55 is rotated the piston assembly 41 will be reciprocated to cause alternate ilow of tluid into the respective cylinder sleeves 35 and ejection thereof when the piston assembly reverses its direction, the iluid being discharged from outlet 23 for each half revolution of the shaft 55.
Since the roller 60 has a slightly convex bearing surface, it is not essential that the cast housing body 11 be machined to a high degree of accuracy. Slight misalignment will be automatically compensated for by the character of the roller bearing surface. Since the crank pin and roller as well as the shaft 55 and bearing assembly 26 are not located within, or subjected to, direct contact with the endless passageway 14, no material pumped into the unit will come in contact with these members nor is there any opportunity for fluid to leak from the pump into the drive parts.
In a. typical assembly, a sleeve assembly is provided having a body portion with an axial length of about 1% inches, with an ID of one inch. The relieved zone adjacent the outer terminal end is typically 1A inch in length, and the sleeve assembly utilized in combination therewith has an axial length of about 7/32 inch. The O ring utilized iu this system is preferably 1% x 1% x /l 5 inches. O rings of that dimension are commercially available.
It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of the invention `as set forth in the appended claims.
What is claimed is:
1. A piston type pump comprising:
(a) a housing body and at least one housing head secured thereto, said housing body and head defining a closed loop and having an endless passageway formed therein, said closed loop surrounding an inner open space;
(b) an inlet in said body communicating with said endless passageway, an outlet in said body spaced from said inlet, and also communicating with said endless passageway;
(c) a pair of open ended cylinders lying mutually in spaced relation between said inlet and said outlet, each communicating with the endless passageway and with said inner open space;
(d) a piston reciprocably positioned in each of said cylinders;
(e) valve means in said passageway interposed between said inlet and each of said cylinders, and valve means in said passageway interposed between said outlet and each of said cylinders; and
(f) a sleeve assembly disposed coaxially within said open ended cylinders, abutment means along said housing head overhanging said valve means and said sleeve assemblies and being arranged to abut and retain said valve means and sleeve assemblies within said pump housing, said sleeve assemblies including a body portion having an outer terminal end contacting said abutment means and further having an externally relieved zone disposed along said body portion and terminating in a shoulder spaced from said outer terminal end by a certain predetermined axial dimension, a sealing ring having an axial length slightly less than said predetermined axial dimension and being disposed in said relieved zone coaxially with said body portion, and an O ring interposed between said sealing ring and said shoulder, the arrangement being such that said retaining means is arranged to contact said abutment means to normally urge said sealing ring toward said shoulder to expand said O ring into sealing contact with the inner surface of said open ended cylinder.
2. The piston type pump as defined in claim 1 being particularly characterized in that the shoulder formed along the surface of said body portion is disposed ad- 20 jacent said outer terminal end.
References Cited UNITED STATES PATENTS 0 HENRY F. RADUAZO, Primary Examiner Us. C1. xn.