Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2001-11-16
2003-04-29
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S412000, C092S096000, C092S129000, C092S099000
Reexamination Certificate
active
06554587
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to pumps, and more generally to diaphragm pumps and diaphragms used in such pumps.
BACKGROUND OF THE INVENTION
Diaphragm pumps that are driven by an electromagnetic device are well known to those skilled in the art. Diaphragm pumps are often not optimized for certain applications. For example, diaphragm pumps are often single acting (i.e., the working piston or diaphragm of the pump effectively pumps fluid only during a portion of its movement). As another example, diaphragm pumps are designed for pumping only one fluid at a time, despite the fact that it may often be desirable to pump two fluids simultaneously or closely in time. The rapid cycling of the drive mechanisms of such pumps can produce significant operation noise. Further, effectively sealing the electromagnetic or other drive mechanisms from the fluid being pumped is often essential to maintaining safe and effective pump operation, but can be difficult and costly and can adversely impact pump life.
It would be advantageous to provide an electromagnetically driven pump that addresses one or more of these concerns.
SUMMARY OF THE INVENTION
A number of pump embodiments according to the present invention are advantageously dual or double acting, thereby increasing pumping capacity. In addition, some of the pumps of the present invention reduce noise during operation. In some embodiments, the pumps of the present invention have self-priming capabilities. In certain embodiments, the pumps do not rely upon the fluid being pumped for lubrication, can be “run dry” for relatively long periods without incurring damage or without incurring significant damage. The diaphragms of the present invention are preferably configured to effectively seal the fluid being pumped from the electromagnetic drive assemblies, and in some embodiments can instead or in addition function to separate one fluid path through the pump from another. Many of the pumps and pump diaphragms according to the present invention are significantly more efficient, quiet, compact, have relatively long lives, and can be manufactured and assembled at relatively low cost.
In some preferred embodiments of the present invention, the pump includes a housing, a diaphragm, and an electromagnetic assembly. The pump housing has an inlet port, an outlet port, and a chamber in fluid communication with the inlet port and outlet port. As described in greater detail below, such pumps are capable of extended operation, can operate very effectively at high pressures, and have self-priming capabilities.
The diaphragm is preferably sealingly secured in the chamber and extends in at least one direction (and more preferably in both directions) to a sealed relationship with the housing. Some embodiments of the diaphragm have a central portion, a peripheral portion, and first and second projections. The central portion is adapted for movement relative to a housing of the pump to pump a fluid through the housing. The peripheral portion is preferably joined to the central portion and is adapted to be sealingly secured to the housing of the pump. The first and second projections (if employed) preferably extend generally axially outwardly from the central portion. Each of the first and second projections can include a sealing region that is adapted to be secured to the pump housing.
Although a number of different diaphragm shapes are possible, the diaphragm preferably has a central axis generally circumscribed by the peripheral portion. The first and second projections (if employed) preferably also circumscribe the central axis, and can be tubular structures or can have other shapes as desired.
Preferably, the diaphragm extends axially in either or both directions into apertures shaped to receive the axially-extending parts of the diaphragm. The diaphragm is preferably sealingly secured within first and second apertures located on respective axial sides of the diaphragm, and cooperates with the housing to define a fluid passageway between the inlet port and the outlet port. Specifically, some preferred diaphragm embodiments of the present invention include first and second seal portions configured to fluidly isolate the first and second apertures, respectively, from the fluid passageway between the inlet and outlet ports. The first and second seal portions extend axially away from each other and are preferably secured to the housing.
In some embodiments, the diaphragm includes an inner element or central portion that is more rigid than an outer portion of the diaphragm substantially surrounding the inner element. Force is preferably exerted by the plunger and a biasing assembly (described below) against the relatively rigid inner element of the diaphragm. For example, the relatively rigid inner element can be contacted and pushed or pulled by the plunger and the bias assembly, which lends sufficient strength and rigidity to the diaphragm such that the diaphragm can provide effective pumping action to pump fluid through the chamber. The relatively flexible outer portion of the diaphragm preferably allows the diaphragm to be sealingly secured to the housing while allowing oscillation of the diaphragm within the chamber to provide the desired pumping action. Preferably, the outer portion includes a radially extending peripheral zone that is sealingly secured to the housing. The diaphragm preferably has sufficient flexibility to deflect in response to movement of the plunger and the bias assembly without compromising the seals between the diaphragm and the housing.
Any of the diaphragms of the present invention can be structured such that when they are in a relaxed state, they are either substantially neutral or substantially biased in one direction. Thus, in some embodiments, the diaphragm is structured to be neutral when there are substantially no external forces applied thereto. In this respect, the diaphragm can be configured such that the central portion is spaced an equal distance from axially extending distal ends of the first and second projections of the diaphragm, although other relationships between such a central portion and distal ends is possible. In any case, this “neutral” type of diaphragm can be configured so that the central portion is substantially centrally located in the chamber when the pump is non-operative. In other embodiments, the present diaphragm is structured to be biased toward one end of the housing when there are substantially no external forces applied to the diaphragm. In other words, the diaphragm is configured to be biased toward one of the discharge position and the intake position of the pump. In this respect, the diaphragm can be configured such that the central portion is positioned closer to the distal end of the first projection relative to the distal end of the second projection. Such biasing of the diaphragm can provide enhanced pumping efficiency relative to a similar pump with a neutral diaphragm. For example, a diaphragm biased toward the intake position is effective in assisting a bias assembly (described in greater detail below) in returning the diaphragm to the intake position so that fluid flows efficiently into the fluid chamber. The diaphragm can be made of any suitable material effective to provide a diaphragm that functions as described herein. In some embodiments, the diaphragm is made of at least one polymeric material.
The diaphragm of the present invention is movable between a discharge position in which fluid in the fluid chamber is discharged to an cutlet port of the pump, and an intake position, in which fluid is passed from an inlet port of the pump into the fluid chamber.
In some embodiments of the present invention, the pump includes an inlet valve assembly positioned generally upstream of the chamber and adapted to control fluid flow between the inlet port and the fluid passageway. The pump can also include an outlet valve assembly positioned generally downstream of the chamber and adapted to control fluid flow between the fluid passageway and the outlet port. Also, some pu
Dinh Jonathan
Paolini Louis J.
Pascual Joseph A.
Freay Charles G.
Gray Michael K.
Michael & Best & Friedrich LLP
SHURflo Pump Manufacturing Company, Inc.
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