The present disclosure relates, generally, to diaphragm pumps and, more particularly, to hydraulically actuated diaphragm pumps.
Pneumatic diaphragm pumps have been used for pumping one or more fluids. Pneumatic diaphragm pumps generally include at least one pumping chamber having a diaphragm separating a motive fluid chamber for moving a motive fluid and a pump chamber for pumping a working fluid. Compressed air is fed into the motive fluid chamber to expand the diaphragm, which, in turn, causes the working fluid to be pumped through an outlet of the pump chamber. While pneumatic diaphragm pumps utilizing compressed air are effective, they may also be very inefficient and, thus, very costly.
According to one aspect, a diaphragm pump may comprise a housing defining a first pumping chamber, a second pumping chamber, and a hydraulic fluid chamber, a first flexible diaphragm separating the first pumping chamber from the hydraulic fluid chamber, a second flexible diaphragm separating the second pumping chamber from the hydraulic fluid chamber, a rod mechanically linking the first flexible diaphragm and the second flexible diaphragm such that an expansion of one of the first and second flexible diaphragms exerts a contraction force on the other of the first and second flexible diaphragms, and a piston disposed within the hydraulic fluid chamber and configured to reciprocate to cause a hydraulic fluid contained within the hydraulic fluid chamber to alternately exert an expansion force on the first and second flexible diaphragms.
In some embodiments, the diaphragm pump may further comprise a motor operatively connected to the piston to cause reciprocal movement of the piston. The motor may comprise a rotatable output shaft, an arm having a first end attached to the output shaft, and a roller bearing attached to a second end of the arm opposite the first end. The piston may comprise a cavity receiving the roller bearing, such that rotation of the output shaft causes movement of the roller bearing within the cavity, thereby causing reciprocal movement of the piston.
In some embodiments, the diaphragm pump may further comprise a mechanism configured to deactivate the motor upon detection of a stall in the pump. The mechanism may comprise one or more motion sensors configured to sense ends of a stroke of the piston. The mechanism may comprise a motor overcurrent detection circuit configured to measure a current drawn by the motor and to deactivate the motor when the current is greater than a pre-determined level. The mechanism may comprise a clutch disposed between the output shaft of the motor and the piston, the clutch being configured to disengage when a torque between the output shaft and the piston exceeds a mechanically-set threshold.
According to another aspect, a diaphragm pump may comprise a housing defining a first working chamber and a second working chamber, a first flexible diaphragm separating the first working chamber into a first pump chamber and a first motive fluid chamber, a second flexible diaphragm separating the second working chamber into a second pump chamber and a second motive fluid chamber, a channel in fluid communication with the first and second motive fluid chambers, a rod mechanically linking the first and second flexible diaphragms, a piston disposed within the channel and configured to reciprocate to cause a hydraulic fluid contained within the channel and the first and second motive fluid chambers to alternately exert an expansion force on the first and second flexible diaphragms, a motor operatively connected to the piston and configured to drive reciprocal movement of the piston, and a clutch operatively connected between an output shaft of the motor and the piston, the clutch being configured to deactivate the motor upon detection of an overload condition.
In some embodiments, the rod may be configured to simultaneously contract one of the first and second flexible diaphragms as the other of the first and second flexible diaphragms expands. The motor may further comprise an arm having a first end attached to the output shaft and a roller bearing attached to a second end of the arm opposite the first end. The piston may comprise a cavity receiving the roller bearing, such that rotation of the output shaft causes movement of the roller bearing within the cavity, thereby causing reciprocal movement of the piston. The clutch may be configured to be engaged when a torque between the output shaft and the piston is below a mechanically-set threshold and to be disengaged when the torque between the output shaft and the piston exceeds the mechanically-set threshold.
According to yet another aspect, a method of operating a diaphragm pump comprising a housing defining first and second pumping chambers and a hydraulic fluid chamber, a first flexible diaphragm separating the first pumping chamber from the hydraulic fluid chamber, a second flexible diaphragm separating the second pumping chamber from the hydraulic fluid chamber, a rod mechanically linking the first and second diaphragms, a piston disposed within the hydraulic fluid chamber, and a motor operatively connected to the piston is disclosed. The method may comprise activating the motor to drive reciprocal movement of the piston, the reciprocal movement of the piston causing alternating expansion of the first and second flexible diaphragms, the rod causing alternating contraction of the first and second flexible diaphragms, and deactivating the motor upon detection of a stall condition within the pump.
In some embodiments, deactivating the motor may comprise disengaging a clutch operatively connected between an output shaft of the motor and the piston when a torque between the output shaft and the piston exceeds a mechanically-set threshold. Deactivating the motor may comprise measuring a current drawn by the motor and deactivating the motor if the measured current is greater than a pre-determined level. Deactivating the motor may comprise sensing motion of the piston near an end of a stroke of the piston and deactivating the motor if motion of the piston has not been detected for a pre-determined period of time.
The concepts described in the present disclosure are illustrated by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference labels have been repeated among the figures to indicate corresponding or analogous elements.
While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.
Referring now to
In an illustrative prior art embodiment, as seen in
The shaft 30 illustrated in
The pump 10 includes one or more inlets 32 for the supply of a motive fluid (e.g., compressed air, or another pressurized gas) to the first and second motive fluid chambers 26, 28 to drive reciprocation of the diaphragms 18, 20 and the shaft 30. The pump 10 may be alternately connected to the inlets 32. Alternatively, one or more valves 34 may be connected to one or more inlets for alternately supplying the motive fluid to the first and second motive fluid chambers 26, 28. When the valve 34 supplies motive fluid to the motive fluid chamber 26, the valve 34 places an exhaust assembly 36 in communication with the other motive fluid chamber 28 to permit motive fluid to be expelled therefrom. Conversely, when the valve 34 supplies motive fluid to the motive fluid chamber 28, the valve 34 places the motive fluid chamber 26 in communication with the exhaust assembly 36. In the illustrative embodiment of the pump 10, movement of the valve 34 between these positions is controlled by a solenoid valve. As such, by controlling movement of the valve 34, the solenoid valve of the pump 10 controls the supply of the motive fluid to the first and second motive fluid chambers 26, 28.
During operation of the pump 10, as the shaft 30 and the diaphragms 18, 20 reciprocate, the first and second pump chambers 22, 24 alternately expand and contract to create respective low and high pressure within the respective first and second pump chambers 22, 24. The pump chambers 22, 24 each communicate with an inlet manifold 38, 40 that may be connected to a source of fluid 41, 43, respectively, to be pumped and also each communicate with an outlet manifold, or fluid outlet, 42, 44 that may be connected to a receptacle for the fluid 41, 43 being pumped. Check valves 46, 48 ensure that the fluid 41, 43 being pumped moves only from the inlet manifold 38, 40 toward the outlet manifold 42, 44 when an appropriate amount of vacuum pressure is stored within the respective motive fluid chamber 26, 28. Referring to
Referring now to
The shaft 130 illustrated in
Referring to
Prior to operation of the pump 100, an amount of motive fluid F1 in the motive fluid chamber 126 and a portion of the channel 160 in fluid communication with the motive fluid chamber 126 may be generally the same as an amount of motive fluid F2 in the motive fluid chamber 128 and a portion of the channel 160 in fluid communication with the motive fluid chamber 128.
As the electric motor 162 rotates an output shaft 164, the arm 166 and the roller bearing 168 rotate with the output shaft 164. The roller bearing 168 moves back and forth along the cavity 170 of a piston 172 to accommodate the rotation of the arm 166. When the roller bearing 168 reaches a first edge 180 of the cavity 170, and the arm 166 continues to rotate, the piston 172 is moved along the channel 160 toward the chamber 114. Likewise, as the roller bearing 168 reaches a second edge 182 of the cavity 170, and the arm 166 continues to rotate, the piston 172 is moved along the channel 160 toward the chamber 116. The piston 172 may be positioned within the channel 160 such that the motive fluids F1, F2 may be prevented from passing the piston 172. In an illustrative embodiment, a seal may be formed around one or more portions of the piston 172 to prevent movement of motive fluid F1, F2 past the piston 172, while still allowing movement of the piston 172. As the piston moves, the overall space in which the motive fluids F1, F2 are held increases and decreases, thereby causing alternating low and high pressure against the flexible diaphragms 118, 120, which, in turn, causes the flexible diaphragms 118, 120 to contract and expand.
As seen in
A mechanism for overload or stall protection may be implemented within the pump 100 of
In an illustrative embodiment of stall protection, as seen in
In a further illustrative embodiment, the stall protection may be implanted within circuitry as a motor overcurrent detection circuit that may deactivate the motor 162 when a measured current drawn by the electric motor 162 is greater than a pre-determined safe level.
In a still further illustrative embodiment of stall protection, a position of the piston 172 may be monitored by motion sensors (e.g., Hall effect sensors) mounted at or near an end of each piston stroke. If no signal is received from a sensor within a particular time interval (e.g., due to a blockage in the system, breakage of the connection between the motor 162 and the piston 172, etc.), the motor 162 may be deactivated.
In illustrative embodiments, the pump 100 may include one or more mechanisms for compensating for leakage within the pump 100, for example, from the motive fluid chambers 126, 128. At times, motive fluid F1 or F2 may escape from the pump 100, which can create issues with operation of the pump 100. It is therefore desirable to replace lost motive fluid F1, F2. Referring to
While a single portion 300, 302 is shown in conjunction with each motive fluid chamber 126, 128, multiple fluid ports may alternatively be used. Still further, while two motive fluid reservoirs 306, 308 are depicted, a single reservoir may alternatively communicate with both (or all, if more than two total) ports 300, 302. In any of the embodiments described herein, the rod 130 may be positioned toward the inlet manifolds 200, 202 or toward the outlet manifolds 208, 210. In alternative embodiments, any other suitable mechanism or method for compensating for leakage may be additionally or alternatively used within the pump 100.
While certain illustrative embodiments have been described in detail in the figures and the foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, systems, and methods described herein. It will be noted that alternative embodiments of the apparatus, systems, and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the apparatus, systems, and methods that incorporate one or more of the features of the present disclosure.