Patent Application
20080149671
1. Field of the Invention
This invention relates broadly to pump sprayers preferably of the trigger-actuated hand-operated type. More particularly, this invention relates to the pressure build-up discharge assembly, and spring biased valve therefor, located at the fluid discharge nozzle end of such sprayers.
2. State of the Art
Many known pump sprayers have discharge valves at the nozzle end of the discharge passage for throttle valving the fluid pressure during pumping. The discharge valve forms part of an assembly including a spinner probe having spin mechanics of some type to effect a spinning or swirling action of the pressurized fluid to produce a spray discharge out of the orifice. Resilient means in the form of a separate coil spring or an integral plastic molded spring is provided for urging the valve onto its seat into a closed position. The valve opens in response to fluid pressure in the discharge passage which exceeds the closing force of the spring.
Such known sprayer discharge valves are typically of the throttling type, permitting the operator to control the actuation rate of the trigger sprayer, and such actuation rate determining the flow velocity. The flow velocity through the spin mechanics determines the size of the spray plume or more precisely the rotational velocity of the annular fluid sheet exiting from the orifice. The greater the velocity (the more energy in the spray plume) the thinner the annular sheet and the finer the particles created by breakup in the atmosphere. Thus the operator's pumping stroke rate varies the size and distribution range of the spray particles.
New product formulations require a narrow distribution range of particles and a predicted mean particle size. Thus, it was desirable to effectively regulate the operator's pumping stroke velocity and thereby produce a well-defined particle size and distribution range of fluid issuing from the discharge orifice as a fine mist spray.
Co-owned U.S. Pat. No. 5,522,547 to Dobbs, the teaching of which is hereby incorporated by reference herein, achieves this objective by the provision of a two-stage pressure build-up discharge valve assembly mounted at the end of the discharge nozzle surrounded by a nozzle cap. A high pressure throttle valve incorporating a valve and coil spring is coupled with a second stage low pressure sliding piston. The two stage valve member provides a predetermined pressure threshold which when exceeded by fluid pressure generated by the operator's finger force on the trigger actuator opens immediately permitting the fluid pressure to act upon the low pressure secondary piston abruptly snapping the valve assembly to a fully open flow position. At such position the operator's fingers are effectively caused to travel all or through most of the pump actuation stroke distance before the finger muscles can compensate and adjust to the lower force permitted by the second stage piston. However, when the finger muscles adjust to the lower actuation force and relax, the coil spring abruptly snaps the two-stage valve closed at a predetermined pressure.
At both the beginning of the pumping pressure stroke and at the end of pumping actuation, the two-stage valve snaps open and snaps closed immediately thereby eliminating the formation of large droplets at the beginning and at the end of each pressure stroke, thereby resulting in a uniform, repeatable mist spray.
While the discharge valve assembly described in Dobbs functions very well, the necessity of separate valve and coil spring in the assembly described therein increases the part count. It would be desirable to integrate the valve seat, spring and piston to reduce the number of components required for the assembly.
Several patents disclose a valve, compression spring and piston integrally molded for use in discharge valve assemblies. See, e.g., U.S. Pat. No. 4,153,203 to Tada, U.S. Pat. No. 4,273,290 to Quinn, U.S. Pat. No. 4,958,754 to Dennis, U.S. Pat. No. 4,989,790 to Martin et al., U.S. Pat. No. 5,234,166 to Foster et al., and U.S. Pat. No. 5,716,008 to Nottingham et al. However, such integrated components have disadvantages when used in the discharge valve assembly of the type described in Dobbs.
For example, it is desirable for the spring in a two-stage Doobs type discharge valve assembly to have a limited repeatable throw. Wave-shaped compression springs, which are common in integrated designs, are capable of a relatively large amount of compression. Further, it is desirable for the spring to be stably held within piston chamber in a manner which prevents spring buckling. Standard wave-shaped compression springs are subject to buckling. In addition, an integrated valve, spring and piston should be easy to manufacture. Double helix spring designs like that shown in U.S. Pat. No. 5,234,166 to Foster et al. are difficult to manufacture.
It is therefore an object of the invention to provide an integrated valve and compression spring for use in a discharge valve assembly of a pump sprayer.
It is another object of the invention to provide an integrated valve and compression spring that is easy to manufacture.
It is a further object of the invention to provide a discharge valve assembly in which the compression spring therein has a limited repeatable throw.
It is also an object of the invention to provide a discharge valve assembly in which the compression spring will not buckle within the valve chamber.
In accord with these objects, which will be discussed in detail below, a trigger actuated sprayer is provided with a two-stage pressure build-up discharge valve assembly mounted at an end of a discharge nozzle. The valve assembly is provided in a valve chamber and includes an integrated poppet valve, spring and volume reducer. The volume reducer is intended to take up space within the valve chamber to reduce priming volume.
The spring includes more than one full angular omega-shaped form with relatively flat sides. The flat sides define longitudinally displaced spaces between adjacent omega-forms. Portions of the spring are preferably sufficiently wide to substantially extend across the valve chamber to provide stability to the spring and prevent buckling. The flat sided omega-form construct is relatively easy to manufacture via molding and the ends of such construction provide suitable locations for integrated molding with the valve and the volume reducer.
The valve includes an end seal cone which seats within a small hole in the valve seat of the valve assembly, and a larger poppet which seats against or near the valve seat. In addition, in accord with various embodiments of the invention, the valve may be provided with or without a chevron; i.e., a flange.
Furthermore, the relative locations of the spring and volume reducer can be interchanged. That is, the spring may be located between the valve and volume reducer, or the volume reducer may be located between the valve and spring.
The integrated valve, spring and volume reducer function to permit the valve to operate as a two stage system, as generally described in previously incorporated U.S. Pat. No. 5,522,547 to Dobbs. A predetermined high pressure threshold is initially required to move the seal cone from the valve seat. Such pressure is generated by the operator's finger force on the trigger actuator. Once the valve opens, the fluid pressure is permitted to act upon the low pressure secondary poppet snapping the valve assembly to a fully open flow position. At such position the operator's fingers are effectively caused to travel all or through most of the pump actuation stroke distance before the finger muscles can compensate and adjust to the lower force permitted by the second stage poppet. However, when the finger muscles adjust to the lower actuation force and relax, the integrated flat-sided omega-form spring abruptly snaps the two-stage valve closed at a predetermined pressure.
At both the beginning of the pumping pressure stroke and at the end of pumping actuation, the two-stage valve snaps open and snaps closed immediately thereby eliminating the formation of large droplets at the beginning and at the end of each pressure stroke, thereby resulting in a uniform, repeatable mist spray.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
Turning now to
Referring to
The volume reducer 42 operates to reduce the priming volume of the chamber 32; i.e., to reduce the number of times the trigger must be operated the first time the sprayer is used before spray is discharged from nozzle. In the embodiment shown, the volume reducer 42 is structured as a series of discs 50 displaced along a longitudinal cruciform 52. The discs 50 are smaller than the transverse dimensions of the cruciform 52 to allow fluid flow past the reducer 42 in the axial direction through the chamber 32. A nipple 54 is preferably provided to the forward end of the volume reducer 42.
The poppet valve 46 includes a flat poppet 56 and a central generally frustoconical seal cone 58 located thereon. The seal cone 58 is positioned to be centered relative to the hole 38 in the valve seat 37, and is sized so that it extends at least partially into the hole. In addition, referring to
Referring back to
The relative locations of the spring 44 and volume reducer 42 can be interchanged. That is, the spring 44 may be located between poppet valve 46 and volume reducer 42, as shown in the prior Figures, or turning to
Referring back to
At both the beginning of the pumping pressure stroke and at the end of pumping actuation, the two-stage valve 46 snaps open and closed immediately, thereby eliminating the formation of large droplets at the beginning and at the end of each pressure stroke, and resulting in a uniform, repeatable mist spray.
There have been described and illustrated herein several embodiments of a trigger sprayer, a discharge valve assembly therefor, an integrated valve, spring and volume reducer for the discharge valve, and a particular spring design. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while several variations to certain embodiments of the invention have been disclosed, it is anticipated that alternative embodiments described in the specification may be interchangeably used with any other described embodiments as well. In addition, while certain exemplar size ratios have been disclosed with respect to the spring, it is appreciated that such ratios are exemplar and not meant to limit the invention disclosed herein. Also, while a spring with two and a half omega-forms has been shown, the spring could have fewer or more omega-forms, although it should have more than one full form (i.e., at least one and a half forms so as to generate at least two gaps). Furthermore, while the integrated valve, spring and volume reducer have been described with respect to a trigger actuated sprayer, it is appreciated that such component can be used in the discharge valve assembly of sprayers and even pumps actuated by other means, including but not limited to battery-powered motor-actuated means. Also, where a ball valve is disclosed as a one-way valve, it is appreciated that other one-way valve may be used including but not limited to duck-bill valves. In addition, it is recognized that a spring of the design described, apart from the integrated valve element, may have utility on its own within a discharge valve assembly or otherwise. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed.
