US 3923428 A
A pump having a cylinder connected at both ends to a reservoir containing a source of material to be pumped and a double-ended piston which is reciprocally operated to alternately draw through check valves material from the reservoir and pump the material through check valves into a manifold having a single discharge port.
Description (OCR text may contain errors)
Muted States Patent 1191 1 1 3,923,428 Clark et a1. 1 1 Dec. 2, 1975 PUMPS 445,577 2/1891 Wadsworth 417/568 1,145.733 7/1915 Wright 92/205 [751 Inventors? Rmald John Clark Port Moody; 1 715,212 5/1929 Riggs 92/205 J Douglas Drummnd, Burnaby, 3,113.587 12/1963 Hendlcy .1 137/5195 both of Canada  Assignee: Western Plaster Equipment Co.
Ltd., Burnaby, Canada Primary E.raminerWilliam L. Freeh Assistant ExaminerG. LaPointe  Flled' 1974 Attorney, Agent, or Firm-Carver and Company  Appl. No.: 530,066
Related US. Application Data  Continuation-impart of Ser. No. 370,984, June 18,
1973, abandoned.  ABSTRACT  US. Cl. 417/535; 92/87; 92/205;
137/5195 A pump havmg a cylmder connected at both ends to a ] Int. F16J 1/06; F018 31/00. F04B 21/02 reservoir containing a source of material to be  Field of Search 417/534 535 568' Pumped and a double'ended Piston which is recipw' 37/519 5195 53311 533113 5 cally operated to alternately draw through check 92/2O5, 206 240 valves material from the reservoir and pump the matei rial through check valves into a manifold having a sin-  References Cited gle discharge port UNITED STATES PATENTS 4,026 5/1845 Walther 417/535 2 Claims, 2 Drawing Figures 8/7 65 L////'l /\//I// 75 we) 67 7/ f US. Patent Dec. 2, 1975 Sheet 2 of2 3,923,428
PUMPS CROSSREFERENCE TO OTHER APPLICATIONS This invention is a Continuation-In-Part application of my application Ser. No. 370,984, filed June 18, 1973 now abandoned.
. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to pumps and in particular, but not limited to, pumps for pumping fluid pastes such as plaster, stucco, cement grouts and the like.
2. Prior Art.
In the application of materials such as plaster, stucco, grouts and the like, which are fluid pastes on to other structures it is now common practice to deliver the materials by means of pumps. Pumps used for this purpose must, in order to be most effective, provide substantially uninterrupted delivery so that workmen applying the material can effectively control its placement. As material of this nature, e.g. mortar which contains sand, is highly abrasive, the pumps used must avoid metal to metal contact between piston and cylinder.
Pumps heretofore developed for pumping material of this nature usually incorporate a plurality of single acting pistons to obtain uninterrupted delivery. The piston have flexible cups usually made of leather for sealing sliding contact with the cylinder walls. Pumpsof this nature present piston alignment problems as a metal to metal contact of sliding parts should be avoided.
SUMMARY or THE INVENTION The present invention provides a pump which can provide substantially constant uninterrupted flow of material and which is so constructed that the pistons are self aligning and require no guides for straight reciprocal action:
The pump of the present invention avoids metal to metal contact of slidingparts so as to reduce water when pumping abrasive materials and, furthermoreis relatively inexpensive to manufacture and maintain.
The pump ofithe-present invention has a pair of spaced pistons; each of which has a flexible cup seal mounted at opposite ends of a connecting rod for mutual reciprocal movement in a cylinder which opens at opposite endsinto a pair-of conduits connected with a material reservoir. An operating arm connected to the connecting rod extends upwards through a slot in the cylinder and is connected to reciprocating drive means. Check valves in the conduits operate automatically as the pistons reciprocate'to direct the pumped material into a manifold having a single outlet.
A detailed description following, related to the drawings, gives exemplification of preferred embodiment of the invention which however, is capable of expression in structure other than that described and illustrated.
DESCRIPTION OF THE DRAWINGS FIG. 1 is a central sectional view of one embodiment of pump apparatus of the invention.
FIG. 2 is a central sectional view showing, partially, another embodiment of the apparatus, particularly a piston head thereof.
DETAILED DESCRIPTION Referring to FIG. 1 of the drawings, which illustrates one embodiment of the invention, the pump has a reservoir 10 for receiving material to be pumped. Openings 11 and 12 in the bottom of the reservoir open into discharge conduits l3 and 14, respectively. Both conduits lead to a manifold 15 which has a single discharge opening 16 to which flexible resilient tubing, not shown, can be connected in a conventional manner.
A cylinder 17 in which a double-ended piston assembly 18 is mounted, opens at each end into the conduits 13 and 14, respectively.
A check valve assembly 19 is positioned in the conduit 13 between the discharge opening 11 and the cylinder enabling material from the reservoir to flow into the conduits 13 but preventing return flow. The check valve assembly 19 has a spherical seat 21 for receiving a spherical valve element 22. Travel of the valve element 22 away from the seat is limited by a rod 23 extending diametrically across the conduit 13. One end 24 of the rod fits in a seat 25 in the conduit and the other end 26 of the rod tits in a seat 27 in the shank of a bolt 29 which extends into a suitably tapped opening in the wall of the conduit 13, thus permitting movement of the valve element 22 between an open position as shown in solid outline. The travel of the valve element can be adjusted by using rods 23 of varying diameters.
A similar check valve assembly 31 is positioned in the conduit 14 between the discharge opening 12 and the cylinder. Similar check valves 32 and 33 are positioned in the conduits Band 14, respectively, between the manifold and the cylinder for enabling one way-flow of material into the manifold but preventing return therefrom.
The piston assembly has a pair of spaced apart piston heads 35 and 36 secured at opposite ends of an elongated connecting rod 37, opposite end portions of which are reduced in diameter and threaded to provide threaded axial projections 38 and 39. The piston head 35 is mounted on the projection 38 and includes a cylindrical spacer 41 which serves as a backup plate for a piston cup 42 made of flexible material such as leather. An expansion washer 43 fits over the projection within, and against the face of, the cup. A washer 44, which fits on the projection, is forced against the expansion washer by means of a nut 45 threaded on the projection and locked by a lock nut 46. Axial compression of the expansion washer expands the latter radially outwards so as to force the cup li p into sealing engagement with the cylinder wall.
The piston head 36 is constructed in a manner similar to that described in reference to piston 35.
V The cylinder has a longitudinally extending slot 47 through which an operating arm 48, secured at one end 49 to the rod 37, extends.
A connecting rod 51 connects the opposite end 52 of the operating arm 48 and a crank 53 which is mounted for rotation and coupled to a suitable motor 54. The piston assembly reciprocates between a solid outline position and broken outline position as shown in the drawing.
Reciprocation of the piston, it is seen, results in discharge of material alternately through the conduits l3 and 14 into the manifold 15.
Pulsations of the pumped material out of the manifold are dampened by the action. of the flexible, resilient hose. If the hose is about 50 feet in length the material is ejected ina substantially constant stream.
To obtain absolute constant flow of material, second cylinder and piston can be connected in parallel to the manifold with the piston connected to. a, driven crank whichis 90 degrees outof phase to.the crank 53..
Maintenance of the flexibilityof the piston cups and lubrication of the cylinder walls is obtained by partially filling the cylinder between the pistons with a suitable fluid lubricant. Due to the sealing effect obtained by compression of the expansion washers, oil cannot flow freely between the piston cups and the cylinder walls.
FIG. 2 shows, partially, another embodiment 60 of the pump. The pump 60 is the same as a pump 9, except in respect of configuration of a piston head and piston rod.
In pump 60 the piston rod 6l which is cylindrical is I reduced at eachend, one end only being shown to provide a cylindrical projection 62 extending axially from an annular shoulder 63, the projection 62 being threadedvat its outer end 64. A cylindrical guide 65 which has a snug slideable fit in thecylinder l7 and has an inner face 66, slideably fits on the projection flush against the piston shoulder 63 and is reduced in diameter at its outer end to provide an annular seat 67 and an annular outer face 69 A plurality of oil passages,
severally.71, extend through the guide and are ported out of the inner and outer annular faces thereof. The annular seat 67 receives a felt washer 73 which fits against the annular face 69 over the oil passages 7l and I cup due to the provision of the guide 65, Furthermore, the felt washer 73 which is in constant communication '35 the apparatus reduces lateral forces against the piston through the passages 71 with the liquid fluid lubricant,
with which thecylinder can be partially filled, serves to maintain the cylinder walls free of grit during apump- I ing operation without allowing excess lubricating fluid to flow into the mortar or grout being pumped.
We claimz l. A pump including:
a. a reservoir for receiving materialsto bepumped,
b. a cylinder disposed below the reservoir,
c. intake conduits connecting each end of the cylinder and the reservoir for permitting flow of material from thereservoir to the cylinder,
(1. discharge manifold having a discharge opening disposed adjacent the cylinder, e. discharge conduits connecting each end of the cylinder with the manifold for enabling flow of material from the cylinder to the manifold,
f. a double-headed piston assembly mounted inthe cylinder for reciprocal movement, said piston assembly including:
i. a piston disposed axially of the cylinder and being of smaller diameter than the cylinder and having axially disposed cylindrical projections ateach end thereof,
ii. a cylindrical guide mounted on the cylindrical projection slideably engaging the cylinder walls,
iii. oil passages extending through an opening out of opposite faces of the guide,
iv. a felt washer having slideable fit with the cylinder mounted on the projection against the outer face of the guide,
v. a pressure washer against the outer face of the felt washer,
vi. a piston cup formed of a flexible material mounted on the projection against the pressure washer,
vii. an expansion washer fitted over the projection against the cup,
viii. a nut threaded on the projection adapted to be tightened against the expansion washer so as to obtain radial expansion of the expansion washer against the cup and radial expansion of the felt washer against the cylinder,
means for reciprocating the piston, check valve assemblies in the intake and discharge conduits for preventing return flow of material from the cylinder back to the reservoir and for preventing return flow of fluid from the manifold back to the cylinder so that material is drawn from the reservoir and pumped into the manifold at each stroke of the piston assembly.
2. A pump as claimed in claim 1 in which each of the checkvalve assemblies includes:
a. a spherical valve seat central of its associated con- 1 duit,
b. a ball check valve element disposed in the conduit at the valve seat for movement into and out of engagement with the seat between valve open and valve closed positions,
0. a seat in the conduit wall,
d. a threaded opening in the conduit wall in diametric opposition to the conduit seat,
e. a threaded member, having a seat, threaded into the threaded opening,
f. a cylindrical rod seated in the conduit wall seat,
and the'threaded member seat for limiting movement of the ball check valve element from the valve closed to the valve open position. 2