Pump apparatus and method

Abstract

Pump apparatus and method. The pump can include a valve assembly and a diaphragm. In some embodiments, the diaphragm can include a convolute that can deform in order to increase a volume of a pumping chamber to provide an internal fluid bypass when a pressure in the pumping chamber exceeds a bypass pressure. In some embodiments, the pump can include a fluid reservoir at least partially defined by a wall with a flow-restrictive conduit in fluid communication with an outlet chamber. A shut-off switch can include an actuator in fluid communication with the fluid reservoir. The fluid reservoir and the flow-restrictive conduit can substantially isolate the shut-off switch from pressure pulses in the outlet chamber.

1 . A pump comprising:
 a valve assembly partially defining a pumping chamber; and   a diaphragm coupled to the valve assembly, the diaphragm partially defining the pumping chamber, the diaphragm including a convolute, the convolute deforming in order to increase a volume of the pumping chamber to provide an internal fluid bypass when a pressure in the pumping chamber exceeds a bypass pressure.   
     
     
         2 . The pump of  claim 1 , wherein the convolute deforms by at least one of stretching and flexing in order to increase the volume of the pumping chamber. 
     
     
         3 . The pump of  claim 1 , wherein the convolute flexes from a concave shape to a convex shape in order to increase the volume of the pumping chamber. 
     
     
         4 . The pump of  claim 1 , wherein the convolute enables low-stress deformation of the diaphragm. 
     
     
         5 . The pump of  claim 1 , wherein the diaphragm includes a piston integrally formed with the diaphragm by the convolute. 
     
     
         6 . The pump of  claim 1 , wherein the diaphragm includes three pistons and three convolutes. 
     
     
         7 . The pump of  claim 1 , wherein the diaphragm includes a piston and the convolute includes a trough portion, and wherein a distance between the piston and the trough portion is substantially constant around the piston. 
     
     
         8 . The pump of  claim 1 , wherein the diaphragm includes a piston and the convolute includes a trough portion, and wherein a first distance between the piston and the trough portion at an interior portion of the diaphragm is greater than a second distance between the piston and the trough portion at an exterior portion of the diaphragm. 
     
     
         9 . The pump of  claim 1 , wherein the diaphragm includes a piston and the convolute includes an inner annulus extending from the piston. 
     
     
         10 . The pump of  claim 8 , wherein the inner annulus extends from the piston substantially tangentially. 
     
     
         11 . The pump of  claim 1 , wherein the diaphragm includes a piston, and wherein the piston has a gradually changing diameter with a substantially continuous curved profile extending from the convolute. 
     
     
         12 . The pump of  claim 1 , wherein the convolute includes an annulus that flexes from a concave shape to a convex shape above the bypass pressure. 
     
     
         13 . The pump of  claim 1 , wherein the convolute is positioned at an angle of about two degrees to about four degrees with respect to a plane of the diaphragm. 
     
     
         14 . The pump of  claim 1 , wherein the diaphragm is constructed of a single piece of resilient material. 
     
     
         15 . The pump of  claim 1 , wherein the diaphragm includes a channel to form a seal with the valve assembly. 
     
     
         16 . A method of operating a pump, the method comprising:
 receiving fluid into a pumping chamber;   increasing pressure in the pumping chamber;   exceeding a bypass pressure; and   increasing a volume of the pumping chamber by deforming a convolute in order to provide an internal fluid bypass.   
     
     
         17 . The method of  claim 16 , and further comprising deforming the convolute by at least one of stretching and flexing in order to increase the volume of the pumping chamber. 
     
     
         18 . The method of  claim 16 , and further comprising flexing the convolute from a concave shape to a convex shape in order to increase the volume of the pumping chamber. 
     
     
         19 . The method of  claim 16 , and further comprising enabling low-stress deformation of the diaphragm. 
     
     
         20 . The method of  claim 16 , and further comprising increasing a first distance between a piston and a trough portion of the convolute at an interior portion of the diaphragm and decreasing a second distance between the piston and the trough portion of the convolute at an exterior portion of the diaphragm. 
     
     
         21 . The method of  claim 16 , and further comprising flexing an annulus of the convolute from a concave shape to a convex shape above the bypass pressure. 
     
     
         22 . A pump comprising:
 a pump head assembly defining an outlet chamber;   a fluid reservoir at least partially defined by a wall including a flow-restrictive conduit in fluid communication with the outlet chamber; and   a shut-off switch having an actuator in fluid communication with the fluid reservoir, the fluid reservoir and the flow-restrictive conduit substantially isolating the shut-off switch from pressure pulses in the outlet chamber.   
     
     
         23 . The pump of  claim 22 , wherein the shut-off switch disconnects power from a motor. 
     
     
         24 . The pump of  claim 22 , wherein the shut-off switch is actuated when a second fluid pressure in the fluid reservoir exceeds a shut-off pressure after a first fluid pressure in the outlet chamber has already exceeded the shut-off pressure. 
     
     
         25 . The pump of  claim 22 , wherein the shut-off switch is biased with a spring and the shut-off pressure is adjustable by varying a preload on the spring. 
     
     
         26 . The pump of  claim 25 , wherein the spring is coupled to an adjustment screw that rotates to vary the preload. 
     
     
         27 . The pump of  claim 22 , wherein the shut-off switch is a normally-closed switch. 
     
     
         28 . The pump of  claim 22 , wherein the actuator is a diaphragm actuator. 
     
     
         29 . The pump of  claim 22 , wherein the fluid reservoir is a pressure-dampening reservoir that impedes movement of the actuator. 
     
     
         30 . The pump of  claim 22 , wherein the flow-restrictive conduit is a pinhole aperture with a diameter of about 0.025 inches and a length of about 0.30 inches. 
     
     
         31 . The pump of  claim 22 , wherein a length of the flow-restrictive conduit is greater than a thickness of the wall of the fluid reservoir. 
     
     
         32 . A method of operating a pump, the method comprising:
 receiving fluid within an outlet chamber;   restricting flow into a fluid reservoir in fluid communication with the outlet chamber;   actuating a shut-off switch in fluid communication with the fluid reservoir when a pressure in the fluid reservoir exceeds a shut-off pressure; and   isolating the shut-off switch from pressure pulses in the outlet chamber.   
     
     
         33 . The method of  claim 32 , and further comprising disconnecting power from a motor when the pressure in the fluid reservoir exceeds the shut-off pressure. 
     
     
         34 . The method of  claim 32 , and further comprising actuating the shut-off switch when a second fluid pressure in the fluid reservoir exceeds the shut-off pressure after a first fluid pressure in the outlet chamber has already exceeded the shut-off pressure. 
     
     
         35 . The method of  claim 32 , and further comprising biasing the shut-off switch. 
     
     
         36 . The method of  claim 32 , and further comprising adjusting the shut-off pressure. 
     
     
         37 . The method of  claim 36 , and further comprising rotating an adjustment screw to adjust the shut-off pressure.