Reciprocating Pump

Abstract

A positive displacement pump can include a pump mechanism having a shaft configured to rotate about its long axis; a screw rod having a continuous thread around the circumference of the screw rod, the thread configured with an upward and downward thread component wherein the screw rod is operatively coupled to the shaft and reticulates along the long axis when the shaft is rotated about the long axis; a stylus positioned to engage the thread of the screw rod; cylindrical body forming a cavity configured to house at least a portion of the screw rod and allow movement of the screw rod along the long axis of the cylindrical body providing a pumping action in the cylindrical body cavity; an inlet and an outlet provided in the cylindrical body walls fluidly coupling the cylindrical body cavity with one or more external fluid paths.

Claims

1. A positive displacement pump comprising a pump mechanism having: (i) a shaft configured to rotate about its long axis; (ii) a screw rod having a continuous thread around the circumference of the screw rod, the thread configured to have an upward thread component and a downward thread component, wherein the screw rod is operatively coupled to the shaft and reticulates along the long axis when the shaft is rotated about the long axis; (iii) a stylus positioned to project into the cavity and engage the thread of the screw rod; (iv) cylindrical body forming a cavity configured to house at least a portion of the screw rod and allow movement of the screw rod along the long axis of the cylindrical body providing a pumping action in the cylindrical body cavity by expanding and displacing the volume of the cylindrical body; and (v) one or more inlets and one or more outlets provided in the cylindrical body walls fluidly coupling the cylindrical body cavity with one or more external fluid paths.

2. The pump of claim 1, further comprising a pump motor aligned along the long axis of the pump mechanism configured to rotate the shaft when in use.

3. The pump of claim 1, wherein one or more inlet, one or more outlet, or one or more inlet and outlet is coupled to a valving mechanism.

4. A system comprising a plurality of pumps of claim 1.

5. The system of claim 4, wherein the pumps are configured in a series with respect to fluid flow.

6. The system of claim 4, wherein the pumps are configured parallel with respect to fluid flow.

7. The system of claim 4, wherein the system includes both pumps in series and in parallel.

Description

DESCRIPTION OF THE DRAWINGS

[0019] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of the specification embodiments presented herein.

[0020] FIG. 1 illustrates an example of a diamond screw pump at the initiation of a stroke.

[0021] FIG. 2 illustrates an example of a diamond screw pump mid stroke.

[0022] FIG. 3 illustrates an example of a diamond screw pump at the bottom of a stroke.

[0023] FIG. 4 illustrates a system with multiple pumps in a vertical or linear configuration, minimizing the pump mechanism footprint.

[0024] FIG. 5 illustrates another system with multiple pumps in a horizontal configuration connected to a motor via a bearing mechanism.

DESCRIPTION

[0025] The following discussion is directed to various embodiments of the invention. The term “invention” is not intended to refer to any particular embodiment or otherwise limit the scope of the disclosure. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.

[0026] One of the most common types of pumps is a positive displacement pump, which is a type of pump that uses a mechanism to entrap a certain amount of fluid and force it in a direction. A specific type of positive displacement pump is a reciprocating pump, which utilizes a component that repeatedly enters and exits a cavity. When the component enters the cavity, it displaces the fluid that is in the cavity, and when the component exits the cavity, it draws new fluid into the cavity. The flow of fluid into and out of the cavity are usually regulated by one-way valves. One example of a reciprocating pump would be the cylinders/pistons in a car engine.

[0027] FIG. 1, FIG. 2, and FIG. 3 illustrate one embodiment of a positive displacement or reciprocating pump having a diamond screw mechanism (a threaded surface regulating the movement of the screw rod in a cylinder). FIG. 1 illustrates one example of the pump mechanism at about the top of a stroke, FIG. 2 illustrates one example of the pump mechanism mid-stroke, and FIG. 3 illustrates one example of the pump mechanism at about bottom stroke. The reciprocating pump comprises shaft 101, screw rod 102, cylindrical body or cylinder 103 forming a cavity 105, stylus 104, and valving system (106, 107). Screw rod 102 forms or has a thread or groove 108 spiraling around the circumference of screw rod 102 down the length of screw rod 102 and back to the top forming a continuous diamond screw pattern (e.g., a diamond screw). The thread or groove 108 can engage with stylus 104. When in operation with the shaft being rotated about its long axis the stylus engaging with the thread or groove results in rotation of the screw rod 102 as it extends into and retracts from cavity 105 formed by cylindrical body 103.

[0028] A diamond screw, sometimes referred to as a level-wind screw or reversing screw, is a rod that has a single screw thread or groove (e.g., 108) that turns both clockwise and counterclockwise. The clockwise and counterclockwise threads are routed into each other at each end of the rod. The rod is typically fixed (with the ability to rotate about the axial direction) and a component (stylus 104), which mates with the diamond screw thread, is placed on it. As the rod turns, the component slides back and forth from rod end to rod end. Because of the diamond screw thread, the rod only needs to rotate in one direction in order to move the component in both directions. In certain aspects the clockwise pitch and counter-clockwise pitch are the same or approximately the same (the term “pitch” refers to the vertical distance between adjacent turns of the separator at corresponding locations). In other aspects the clockwise pitch and the counter-clockwise pitch differ. The clockwise pitch can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm, cm, dm, or m (depending on the size of the pump), including all values and ranges there between. The counter-clockwise pitch can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm, cm, dm, or m (depending on the size of the pump), including all values and ranges there between. The clockwise thread angle can be 0.5 to 89.5, 1 to 89.5, 10 to 89.5, 20 to 89.5, 30 to 89.5, 40 to 89.5, 50 to 89.5, 60 to 89.5, 70 to 89.5, 80 to 89.5, 0.5 to 70, 1 to 70, 10 to 70, 20 to 70, 30 to 70, 40 to 70, 50 to 70, 60 to 70, 0.5 degree to 50, 1 to 50, 10 to 50, 20 to 50, 30 to 50, 40 to 50, including all values and ranges there between, degree with respect to the long axis of the screw rod. The counter-clockwise angle can be 0.5 to 89.5, 1 to 89.5, 10 to 89.5, 20 to 89.5, 30 to 89.5, 40 to 89.5, 50 to 89.5, 60 to 89.5, 70 to 89.5, 80 to 89.5, 0.5 to 70, 1 to 70, 10 to 70, 20 to 70, 30 to 70, 40 to 70, 50 to 70, 60 to 70, 0.5 degree to 50, 1 to 50, 10 to 50, 20 to 50, 30 to 50, 40 to 50 degree, including all values and ranges there between, with respect to the long axis of the screw rod.

[0029] The idea for a diamond screw pump is to use the diamond screw rod 102 to displace a fluid. By rigidly fixing the stylus 104 the rotation of the rod 102 will cause rod 102 to move in and out of cavity 105, linearly along the shaft 101. The end of the reciprocating screw rod can be positioned in cavity 105, ultimately drawing fluid in and pushing fluid out of the cylindrical body 103. When used in combination with a stationary motor to drive a diamond screw pump, shaft 101 needs to be inserted to the screw rod 102. Shaft 101 will slide in and out of screw rod 102 as it reciprocates and moves in and out of cavity 105. Shaft 101 can be operatively coupled to a motor 110 or other type of drive or control mechanism. In certain aspects the pump can have 1, 2, 3, 4 or more cylindrical bodies and 1, 2, 3, 4, 5, 6, or more valves operatively coupled to various flow paths within or between cylindrical bodies.

[0030] In certain aspects 1, 2, 3, 4, 5, 6, 7, or more pumps can be fluidically couple or operatively couple to form a pump system. Multiple pumps can be oriented, with respect to each other, vertically, horizontally, circumferentially, staggard, or in any other configuration.

[0031] In one embodiment two or more screw rods can be assembled and connected to the same motor 110 and shaft 101 (see FIG. 4 for an example). In certain configuration the assembly can have an optional wall 420 separating the cylinder body 103 into multiple compartments, e.g., a top and bottom compartment. In the top compartment valving system 106a/107a can provide for inlet flow A and outlet flow B for Screw Rod 102a and the in the bottom compartment valving system 106b/107b can provide for inlet flow C and outlet flow D for Screw Rod 102b. In certain aspects outlet flow B could feed into inlet floe C to pump fluid twice. Without a wall 420 separating the cylinder body into multiple compartments inlet flow A and outlet flow B for Screw Rod 102a and Screw Rod 102b inlet flow C and outlet flow D for Screw Rod 102b could not exist; so only fluid being pumped would be from A to B by both screw rods 102a and 102b. Inlet flow A and inlet flow C could come from same reservoir, and/or outlet flow B and out flow D could go to same reservoir. Screw rods 102a and 102b would rotate at same rate, but move at different axial rates determined by thread 108a and 108b. Threads can be configured to have inconsistent spacing to create nonlinear flow rates (e.g., the right-handed thread could start at 0.5″ spacing and finish at 0.125″ spacing). The motor can have variable speed to create nonlinear flow rates. In other aspects, the threads on different screw rods can be configured differently. The cylindrical bodies can be configured with additional inlets and/or outlets. Each screw rod can be configured to pump different fluids (or multiple different fluids depending on number of inlet or outlet ports). Various system or pump configurations can use, implement, or incorporate one more design features of a screw pump as described herein.

[0032] FIG. 5 illustrates an example of a horizontal configuration. In certain aspects two or more pumps 102a and 102b positioned on separate axis are connected to one or more motor 110 via different shafts 101a and 101b via gears 511a, 510, 511b. In certain aspects the gear ratio can be adjusted to alter rotation speeds of each screw rod 102a, 102b independently. A motor 110 can have variable speeds to create nonlinear flow rates. As illustrated in FIG. 5, A represents the inlet flow through valve 107a and B represents the outlet flow through valve 106a for Screw Rod 102a while C represents the inlet flow through valve 107b and D represents the outlet flow through 106b for Screw Rod 102b. In certain aspects, outlet flow B can feed into inlet flow C to pump fluid twice, inlet flow A and inlet flow C can come from same or different reservoirs, outflow B and outlet flow D can go to same or different reservoir. In certain aspects the gearing and groove pitch can be selected independently so that the screw rods could rotate at same or different rates, and move at same or different axial rates determined by threading 108a, 108b. Threads can have inconsistent spacing to create nonlinear flow rates (e.g., the right-handed thread could start at 0.5″ spacing and finish at 0.125″ spacing). Threads on different screw rods could be the same or different. Additional inlets and outlets can be added to cylindrical body(s) 103a and/or 103b. Each screw rod 102a, 102b could pump the same or different fluids (or multiple different fluids depending on number of inlet or outlet ports). Certain designs or configurations can implement any design features of single screw pump described herein.

[0033] In other embodiments a vertical and horizontal configuration can be combined in a single pumping system. Depending on the pump (or combination of pump) designs, any flow profile could be created: a constant flow, waveform flow (square, sinusoidal, etc.), linear ramp up/down flow, nonlinear ramp up/down flow, intermittent flow, or any combination of the above.

[0034] As with any positive displacement pump, the fluid's direction needs to be regulated. One example of regulating fluid flow is by using appropriate valving (e.g., 106 and/or 107). In one example fluid flow can be achieved with two one-way valves. One valve would be oriented so that it only lets fluid enter the cavity and the other valve would be oriented so that it only lets fluid exit the cavity. This allows the reciprocating rod to pull fluid into the cavity as it retracts (up stroke) and push fluid out of the cavity as it extends (down stroke).

[0035] In certain embodiments multiple inlets and/or outlets can be incorporated into the cylindrical body. This configuration can allow for different fluids and/or different sources of the same fluid to move through the cylindrical body. In certain aspects fluids can be mixed in cavity 105a/105b. In certain aspects, a flow regulating feature can be incorporated on the bottom of the piston (e.g., propeller blades or fins) that would capitalize on the rotating motion of the piston to increase mixing of a fluid in the cylindrical body cavity (whether it's one fluid or multiple fluids). If there was an arm attached to the piston that extended out to the side of the device, then it would move up and down with the piston. If the outlet was routed into a line/tube/hose that was connected to that arm, then the device would essentially spray fluid in a sweeping motion. In certain aspects, if the threads are not machined symmetrically, then it will alter the in/out stroke of the piston. For example, if the right-hand threads had 2 rotations and the left-hand threads had 3 rotations. This would mean it could pull fluid in at one rate and push fluid out at another rate (or vice versa).

[0036] In other embodiments a pump described herein can be one component of a system. The system can include a fluid reservoir fluidically coupled to the pump and other downstream components.

[0037] The relationship between motor torque (T) and the force (F) applied to the fluid can be calculated if the linear distance of rod travel for one rotation (pitch, L), pitch angle (α), mean diameter (d.sub.m), and friction (f) are known. That relationship is shown in the following equation:

[00001]$T=\frac{{\mathrm{Fd}}_m}{2}\left(\frac{L+\pi d_m\mathrm{fsec}\alpha }{\pi d_m-\mathrm{fLsec}\alpha }\right)$

Dividing that force by the surface area of the end face of the screw rod will provide the maximum potential pressure of the fluid. Dimensions of the device can vary depending on application. The circumferences, lengths, and diameters can range from millimeters to meters or more as guided by the relationship shown.

[0038] The device will be manufactured from any rigid materials. Components can be plastic, glass, aluminum, steel, or other rigid material. In certain aspects, the material is selected to be compatible with the fluid to be pumped. In certain aspects, seals (e.g., 0 rings, gaskets, etc.) will be employed and can be chosen based on the character of the fluid been pumped as well.

[0039] Pump devices described herein can be employed in various applications such as but not limited to:

[0040] Vacuum pumps. A vacuum pump incorporating a mechanism described herein can be designed, manufactured, and used to pull fluid out of a location or container.

[0041] Compressors. A compressor incorporating a mechanism described herein can be designed, manufactured, and used to push fluid into a location or container.

[0042] Medical devices. Any medical application that needs to move fluids, either gas or liquid can use or incorporate a device as described herein. It would be particularly helpful for liquid pumping applications that are in need of flow control within the 100 μL/min-1 L/min orders of magnitude. For example, this could be used to drive a flow loop for dialysis, extracorporeal membrane oxygenation, or resuscitation.

[0043] Power generation, oil, or gas. A device as described herein can be used or incorporated into a device or system used to deliver combustible fluids, propellants, water in heat exchangers, or water recirculation.

[0044] The device(s) described herein can be used to extract oil and gas, or transport it via pipelines. The device(s) can be used in irrigation, for example to deliver water and/or pesticides to crops or vegetation.

[0045] The device(s) can be used in water treatment, for example, to transport wastewater to and/or within a water treatment facility or transport clean water away from a water treatment facility.

[0046] In certain aspects the device(s) described herein could be used in amusement parks, for example, to deliver/circulate water to swimming pools, lazy rivers, water slides, etc.

[0047] The device(s) described herein can be used vehicles, for example, to deliver/circulate fuel, engine coolant, refrigerant, windshield wiper fluid, heated/conditioned air, etc.

[0048] The device(s) described herein can be incorporated and/or used anywhere that a normal fluid (gas or liquid) pump is used.