Abstract: A beverage syrup pump system is disclosed including a pump housing having an internal pumping chamber, a pump motor, and a pumping mechanism driven by the motor within the pumping chamber. The pumping mechanism receives a syrup fluid at a first pressure and discharges the fluid at a second pressure which is greater than the first pressure. Connected to the pumping chamber is a cylindrical space with a spring and a plunger having a magnet. The plunger is in contact with a quantity of the fluid at a second pressure and moves along the cylindrical space against the biasing force of the spring. Once the second pressure exceeds a predetermined pressure, the corresponding fluid pressure in the cylindrical space exerts enough force on the plunger to move it past a predetermined point within the cylindrical space such that the magnet causes a reed switch in a first position switch to move to a second position and send a signal to a controller.

Abstract: An exemplary pump-head includes a pump housing having first and second housing portions forming a pump-cavity and a magnet-cavity. The pump-cavity contains a movable pumping element, and the magnet-cavity contains a driven magnet coupled to the movable pumping element. The magnet is driven by a moving external magnetic field, which correspondingly moves the pumping element in the pump-cavity in a pumping manner. The second housing portion has inlet and outlet ports and defines at least respective portions of the magnet-cavity and pump-cavity. The first housing portion is detachable from the second housing portion to allow the pumping element to be accessed and carried away with the first housing portion, without disturbing the second housing portion.

Abstract: A fluid pump having a pump housing that includes at least one expansion joint, provides volume compensation, as needed, to adjust for changes in pressure in the pump housing. Various embodiments automatically and passively reduce static pressure in the pump housing associated with a freezing event, thereby preventing damage to the pump head. Volume compensation is achieved by employing, in each expansion joint, a dynamic seal that allows relative movement of two portions of the pump housing, and a bias that provides a selected counter-force to the movement of the housing portions. The subject pumps are particularly suited for use in automotive and other rugged applications, in which fluid pumps may experience recurring freezing events.

Abstract: Various methods are disclosed for manufacturing pump-heads having a housing enclosing at least one rotary member. In an exemplary method first and second housing portions are provided that collectively, when assembled, define a pump-cavity that accommodates the rotary member(s). The rotary member(s) is assembled into the pump-cavity, along with at least one soluble spacer of a defined thickness that corresponds to a desired clearance of the rotary member relative to the pump-cavity. The spacer contacts a surface of the rotary member facing a corresponding surface of the housing portion. The first and second housing portions are attached together to form the pump-cavity containing the rotary member(s). The soluble spacer is dissolved to provide the desired clearance of the rotary member in the pump-cavity. As the housing portions are attached together, e.g., by adhesive bonding, the spacer establishes the desired clearance of the rotary member(s) in the pump-cavity.

Abstract: Valveless piston pumps are disclosed that are magnetically driven, thereby eliminating a troublesome dynamic seal used on conventional valveless piston pumps. An exemplary embodiment includes a housing defining a bore having a bore axis. A piston is situated in the bore so as to be movable in the bore in a reciprocating manner along the bore axis and in a rotational manner about the bore axis. A magnet is situated in the bore and is coupled to the piston. The magnet is engageable magnetically with a magnet-driving device configured to cause the magnet, and thus the piston, to move in the reciprocating manner and in the rotational manner. An exemplary magnet-driving device is a stator assembly.

Abstract: A fluid dispense system having a computer control system that operatively controls a stepper motor driving a nutating pump. The stepper motor actuates the nutating pump piston through partial revolutions. The computer control system determines the number of stepper motor steps required to pump a desired amount of fluid by the nutating pump by rotating the piston through segments which are less than a full revolution.

Abstract: A fluid dispense system having a computer control system that operatively controls a stepper motor driving a nutating pump. The stepper motor actuates the nutating pump piston through partial revolutions. The computer control system determines the number of stepper motor steps required to pump a desired amount of fluid by the nutating pump by rotating the piston through segments which are less than a full revolution.

Abstract: A system and a method are provided for velocity modulation to create pulseless delivery of a fluid by a pump, particularly a piston pump. The system and method require input of data, such as a user-entered dispense rate or analog current or voltage input proportional to a desired output rate. A timer or counter is pre-loaded from a lookup table stored in a processor. The time or counter is started and, upon detection of an overflow condition, the motor and table pointer are incremented one step. As a result, pulseless operation of a pump is achieved.

Abstract: An encapsulated magnet assembly has a magnet encapsulated during a two-step molding process. The first step includes molding a first molded section over a magnet assembly. The second step of the process includes molding a second molded section over the magnet and the first molded section in such a manner that the entire magnet is covered by the two molded sections completely. A first parting line is defined between the first and second molded sections along an elongate tapered section of the first molded section at the one end of the assembly. A second parting line is defined between the first and second molded sections at a dovetail on the first molded section. An outwardly tapered surface is provided on the dovetail. The two parting lines define leak-free seams between the two molded sections thereby sealingly encapsulating the magnet within the two molded sections.

Abstract: An apparatus for manufacturing herringbone gears with an injection molding process is provided. The apparatus involves the use of two separable mold halves each of which include a mold cavity for molding one half of the gear. Moldable material is injected into the mold halves when they are in a sealing abutting engagement. After the material solidifies, the mold halves are separated and the gear is simultaneously unscrewed from each mold cavity.

Abstract: A method of manufacturing herringbone gears using an injection molding process is provided. The process involves the use of two separable mold halves each of which include a mold cavity for molding one half of the gear. Moldable material is injected into the mold halves when they are in a sealing abutting engagement. After the material solidifies, the mold halves are separated and the gear is simultaneously unscrewed from each mold cavity.

Abstract: A reciprocating piston pump provides pulseless delivery of liquid. It is suitable for use in compact environments or for the delivery of small amounts of liquid, as in chromatographic analysis devices. The pump includes two pistons with pumping chambers that are alternately connected to inflow and outflow lines through a control valve. The control valve moves between a first position in which inflow is directed to the first piston chamber and outflow to the second piston chamber, and a second position in which outflow is directed to the first piston chamber and inflow is directed to the second piston chamber. Each outflow pulse from the piston is sustained longer than each inflow pulse, and the outflow pulses are staggered and partially superimposed to provide substantially pulseless delivery of liquid from the pump. A rotating cam moves the pistons of the pumps and the control valve between their operating positions described above.

Abstract: A gear pump is disclosed having an integrated gear cavity and bearing receptacle that includes a fluid path for lubricating the bearings. The preferred embodiment includes a helical gear pump having a manifold with inlet and outlet ports. The integrated gear cavity and bearing receptacle are located in a one piece molded end cap. The bearing receptacle receives a coupled bearing assembly. Together, the coupled bearing assembly and the bearing receptacle define a supply path outside the bearings along the bearing receptacle and a return path through the bearings so that fluid can pass by, and lubricate, the bearing-axle interface.

Abstract: A pump motor controller for making pump motor speed independent of fluid pressure at the inlet and outlet of the pump. A first embodiment employs feedback to cause pump motor speed to converge to a desired speed established with a reference input signal. Based on this feedback, forward and reverse drive amplifiers in the first embodiment cause the pump motor speed to track the desired speed. A second embodiment employs a controller that produces drive signals to a stepper motor in proportion to a reference frequency. The controller and stepper motor in the second embodiment achieve speed control at low speeds without the use of a feedback control loop.

Abstract: A modified elliptical gear defined by a modified elliptical shape having perpendicularly disposed major and minor axes, and bulged portions projecting outwardly beyond the contour of a true ellipse in peripheral regions between the major and minor axes. A computer is preferably used to rotate a simulated hobbing rack having a row of hobbing teeth around the modified elliptical shape. The outline of the hobbing rack is traced at selected positions during the rack rotation to produce a profile of a modified elliptical gear with projecting gear teeth. A topping shape is superimposed upon the gear profile to selectively top the gear teeth. The modified elliptical gear profile is transmitted to a machining device operable to produce a modified elliptical gear.

Abstract: Pump heads comprising at least two gear-pump chambers are disclosed. Each chamber comprises a housing which defines a corresponding pump cavity. Each cavity contains a driving gear and at least one driven gear and has a separate inlet and outlet. The pump cavities are hydraulically interconnected by a fluid conduit allowing passage whenever the pump chambers are pumping a fluid so as to generate a higher pressure in one cavity relative to the other cavity, of the fluid from the higher-pressure cavity to the lower-pressure cavity sufficient to maintain hydraulic prime of both cavities. The invention is particularly useful for ink jet printing applications.