US2521164A - Pump spray - Google Patents

Description

Patented Sept. 5, 1950 UNITED STATES PATENT OFFICE PUMP SPRAY Stanley A. Hayes, Pasadena, Calif.

Application September 24, 1945, Serial No. 618,285

15 Claims. 1

This invention deals with hand-operated -pump sprays, spray guns and the like in which a sprayhead or other discharge device tends to drain liquid from a container through a pump if it is left at a level below that of the liquid in the container and siphoning is permitted to occur. The invention provides a simple but reliable structure which automatically prevents such siphoning action, and in its preferred form, also provides automatic means for agitating the contents of the container.

A common type of hand spray useful for spreading insecticides, detergents and the like in liquid solution or suspension comprises a container, such as a glass fruit jar, a piston type pump with a hand-operated plunger mounted on the top of the container and projecting downwardly into it, and an oulet line such as a flexible hose or tube fastened to the pump at its inlet end and having a spray-head or nozzle on its discharge end. Such devices are simple to construct and operate, and have a Wide eld of usefulness. However, many such devices are so constructed that the contents of the container will Siphon through the pump and out the outlet line or conduit if the discharge end is left at a level below that of the liquid in the container. This is annoying and may be dangerous when the liquid is oi toxic or corrosive character.

I have developed a spray apparatus of the general type described but provided with a combination of structural elements which cooperate 'to prevent siphoning, and which in its preferred modification is provided with means for automatically agitating during the pumping operation the liquid to be pumped. This latter feature is particularly useful when dealing with slurries or suspensions of iinely divided solids in water-for example such widely applied plant sprays as lime-sulphur or Bordeaux mixture. Moreover, my preferred structure is rugged, inexpensive to construct, and requires less force for operation than guns or sprays of this general type heretofore available.

In essence, my invention contemplates apparatus of the type described having a container for liquid, and a pump mounted on the container with a cylinder projecting downwardly into the container. A tubular plunger is mounted in the cylinder. Its upper end projects outside the container and is connected to a discharge conduit, preferably a ilexible tube, which may have a spray-head or the like on its free end. There is a vent to atmosphere in an upper portion of the wall of the cylinderl and springing means, preferably mounted within the cylinder, are provided for holding the lower end of the plunger at a level above the vent in the cylinder wall except when exterior pressure is exerted to force the :plunger down and thus operate the pump. Should the discharge end of the conduit be left below the level of liquid in the container no siphoning can occur because the lower end of the plunger will draw air from the vent and break the Siphon.

These and other features of the invention are made plain in the following detailed description and the accompanying single figure which is a fragmentary elevation, partly in section, of a preferred type of spray gun.

The apparatus illustrated comprises a container, for example an ordinary glass fruit jar I0 having a neck with an outside thread to which a pump assembly is screwed. l

The pump assembly has an upright cylinder H of circular cross-section which extends concentrically of the jar from a point above its mouth to a point within a short distance of its bottom.

An annular foot valve seat l2 is sweated on the lower end of the cylinder and is provided with an interior raised tubular portion having a flat annular upper face upon which a valve disk I3 sits when the apparatus is at rest. An annular cage or keeper I4 is disposed `within the cylinder above the valve seat, and has an inside diameter such that the valve disk is free to rise in the cage under the inuence of a current of liquid passing upward through the seat. The upper face of the keeper is perforated to permit the passage of water from the jar to the pump cylinder.

A retainer sleeve I5 having an inner flange 15A on its upper end is slidably fitted within the cylinder and rests on the cage or keeper of the foot valve. A frusto-conical helical spring l'l rests its larger end on the flange and extends upward to bear against the under side of a plunger assembly I8. The lower end of the spring is only slightly smaller in diameter than the inside of the cylinder, whereas the upper end is smaller so as to hug the plunger assembly. When the plunger assembly is pushed down, the successive coils of the spring tend to collapse within each other, thus oiering minimum resistance to compression and thrust against the cylinder wall, with the result that the pumping is accomplished with less force than would be the case if the spring hugged the wall of the cylinder for a substantial distance.

The piston assembly comprises a concentrical- 3 ly disposed tubular stem I9 with a threaded lower end bearing an upper nut 2S (which bears against a light upper shoulder 2l on the stem, s0 that its position is easily xed in assembly) followed successively by an upper washer 22, a single pump leather 23 (with its edge turned down against the cylinder wall), a lower washer 24, and a head valve cage 25, threaded on the lower end of thestem@ i x .1 E. The need.. valve ee., has ein chamber with a hemispherical seat upon which rests a ball 26, preferably of resilient material such as semi-hard natural or synthetic rubber (prefer: ably neoprene) thus closing a bore 2l in the bottom of the seat. Vertical grooves (npi hwll) are cut on the end of thestemuover which the cage is screwed to permit 'the Lpassage f liquid around the ball when the latter leaves the seat and rises against the en d of the tube.

4 slanting front face 42 which serves to deflect a stream of liquid ejected from the pipe and spread it as a fan-shaped spray.

The spring within the pump cylinder is of such strength and length that it always forces the upper nut of the plunger assembly up against the lower end of the bushing through which the stem extends, i. e. to the extreme upward position'hof the plrmger assembly. Preferably the 10 s'pri''g is under slight compression even when the plunger is in such position, thus giving a greater degree of positiveness to the action of the device. inside vent or :breather hole i3 of relatively :srlall diameter is Kprovided in the wall of the l5 .pugnppcylinder a short distance below the bottom of the plunger assembly, i. e. the bottom of 'cage 2'5; 'considering the assembly to be in itsmextreme upper position with the upper nut in contact with the bushing. An outside Vent or 30 brieather hole 4d is provided in thecap.- This v "also fis of small diameterfa'nd preferably is p d outjr linje oith'e interior Vent, so that l squi'rte'd thiy l ugh thefinterior ventwill rt haveljas 'apprenne pam tothe outside. gj; 4,' Ihe le'gt'hofstem 'projecting above thelow'er vent as the spring pushes the plunger up from its lower position. In the apparatus described, the liquid thus ejected is simply by-passed back into the jar, for the outside vent is out of the line in which the liquid is propelled from the inside vent.

When suspensions of solids in liquid are placed in the jar, there is a tendency for the solids to settle to the bottom, especially upon standing, so that a restricted amount of agitation of the liquid in the jar is desirable. This is accomplished in the apparatus described by means of a small agitator hole 45 in the disk of the foot valve. As the plunger is lowered, the foot valve closes, but

a small jet of liquid is forced down through the i hole to provide agitation in the jar, especially in the Vneighborhood of the foot Valve, thus inhibiting clogging in that Zone and generally agitating the contents oi the jar. As in the case of the breather holes, the hole or by-pass in the disk should be large enough to project an adequate volume but not so large that pumping efficiency is seriously impaired. In a quart fruit jar sprayer a hole in diameter or even smaller has proved adequate.

The agitator hole could be placed in the wall of the pump cylinder proper or in the valve seat. However, it is preferable to place it in the disk itself and to make the disk of exible material, since in this way the iiexing of the disk and its ilutter up and down tend to keep solid particles from clogging the agitator hole.

The foot valve need not be placed at the bottom of the jar. It could, for example, be placed at the level 0r the flange on the retainer sleeve, but in such case the effect of the jet through the agitator hole in the valve disk would be largely damped; and agitation at the bottom of the jar would be much diminished. The structure illustrate-d is, therefore, to be preferred over the modification suggested, although both are within the scope of the invention.

Ii desired, the spring, instead of being mounted in the cylinder below the plunger, can be placed around the stem between the upper and lower handles, and various other modifications can be made, such as the use of a tension-type coil spring in the cylinder between bushing and plunger proper or a compression-type leaf spring between the handles, the essential being that the spring hold the suction end of the plunger assembly above the breather.

The spray gun illustrated in the ydrawing has been designed with a view toward operation with pressure that can be exerted easily by the average hand. To this end a simple deiiector` type fan-spray head is employed, since this gives a relatively ne spray with minimum effort. To the same purpose the spring in the cylinder is designed to avoid wall friction and only a single plunger leather is provided. It will be understood, however, that other types of spray-heads, springs and plunger leathers may be employed in the practice of the invention.

The spray gun illustrated is particularly useful for wetting surfaces with DDT solutions and the like. Such insecticide solutions should be applied as a spray, as distinguished from a inist, since the lethal effect upon insects is furthered by applying the solution as a nlm to wall surfaces and the like so asA to furnish maximum contact, whereas a mist which hangs in the air does little damage to insects, but is injurious if breathed by higher forms of life.

1. In apparatus of the class described, the combination which comprises a container for liquid, a pump having a cylinder projecting downwardly into the container, and a tubular plunger in the lcylinder having an inlet from the cylinder, an exterior conduit connected to the tubular .plunger having a discharge end which may bedisposed` below the level of liquid in the container, a valve in the tubular piston above the inlet and so constructed that it opens when the plunger is lowered but otherwise remains closed, a vent to atmosphere from a point in the upper portion oi the cylinder chamber, and

Vspring means for holding the inlet above the vent container, a valve in the tubular piston above the inlet and so constructed that it opens when the plunger is lowered but otherwise remains closed, a vent to atmosphere through an upper portion of the wall of the container, a second vent con.- necting an upper portion of the container with an upper portion of the cylinder interior, and spring means for holding the inlet above the vent point when exterior pressure on the plunger is relaxed.

3. Apparatus in accordance with claim 1 in which the valve comprises a cage with a seat and a, ball disposed in the seat but free to move upwardly within the cage.

4. Apparatus according to claim l in which the Vent to atmosphere comprises an orifice through an upper portion of the Wall of the container and a second orice through an upper portion of the wall of the pump cylinder.

5. Apparatus according to claim 1 provided with a foot valve disposed in a lower portion of the pump cylinder and connecting the latter with the container and operating in opposition to the valve on the plunger, and a restricted vent connecting a lower portion of the cylinder with a lower portion of the chamber.

6. Apparatus according to claim 1 provided with a foot valve disposed in a lower portion of the pump cylinder and connecting the latter with the container and having a movable member which acts in opposition to the valve on the plunger by opening as the plunger is raised, and a restricted vent in the member connecting the container with the lower portion of the cylinder.

7. Apparatus according to claim 1 in which the springing means is a coil spring disposed in the cylinder below the plunger and so proportioned that it is continuously under compression.

8. Apparatus according to claim 1 in which the springing means is a coil spring describing the frustrum of a cone and disposed in the cylinder below the plunger.

9. Apparatus according to claim 1 in which the springing means is a coil spring describing the frustrum of a cone and disposed in the cylinder below the plunger with its big end down.

10. In apparatus of the class described, the combination which comprises a container for liquid, a pump having a cylinder projecting downwardly into the container, a tubular plunger in the cylinder with an inlet from the cylinder, an

exterior conduit connected to the tubular plunier and having a discharge:v end that may be disposed below the level of liquid inthe container, a venting means to atmosphere in an. open portion of the cylinder, and springing means for holding the plunger inlet above the vent.

11. Apparatus according to claim 10 provided with a disk-type foot valve at the bottom `of the cylinder, the disk of the vaive :being resilient and having a small orifice therein for electing a iet of .iluid into the container.

12. Apparatus according to claim 10 in 'which the springing means is a hel-ical coil wound in frusto-conical shape and disposed inthe cylinder below the plunger.

13. Apparatus according to claim 10 provided with a ball-type check valve in the tubular plunger above the inlet, with Ia ball of resilient material that seats when the plunger is raised.

the venting means mmprises an orifice inthe cyl- REFERENCES `CIIED The following references are of record in the ''le of this patent:

UNITED STATES PATENTS Number Name Date 262.561 Bennett Aug. l5, 18.82 1,831,384 .Gromestein Nov. 10, 1931 2,169,209 Anderson Aug. 415, 1939 *kn* 4.4 l

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