Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
  • F04B43/04—Pumps having electric drive
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
  • F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/0009—Special features
  • F04B43/0081—Special features systems, control, safety measures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
  • F04B43/06—Pumps having fluid drive
  • F04B43/067—Pumps having fluid drive the fluid being actuated directly by a piston
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
  • F04B49/06—Control using electricity
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
  • F04B49/06—Control using electricity
  • F04B49/065—Control using electricity and making use of computers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
  • F04B49/08—Regulating by delivery pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B2203/00—Motor parameters
  • F04B2203/02—Motor parameters of rotating electric motors
  • F04B2203/0201—Current
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B2203/00—Motor parameters
  • F04B2203/02—Motor parameters of rotating electric motors
  • F04B2203/0207—Torque
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B2205/00—Fluid parameters
  • F04B2205/05—Pressure after the pump outlet

Definitions

• the present invention is directed to a control system for pumps and in particular to a control system to a controller using current to maintain a constant fluid pressure.
• Diaphragm pumps are used for a variety of purposes and applications and often require maintaining constant fluid pressure even under varying load conditions.
• Diaphragm pumps generally include a diaphragm, a pumping chamber, and a piston acting on hydraulic fluid on a first side of the diaphragm and separated from the pumping chamber by the diaphragm.
• the piston assembly is adapted to reciprocate and move between a first position and a second position to actuate the diaphragm.
• the diaphragm flexes away from the pumping chamber allowing the pumping fluid to be drawn into the pumping chamber through an inlet passage.
• the diaphragm flexes toward the pumping chamber and causes the fluid of the pumping chamber to be discharged through a discharge passage.
• the present invention is directed to a pump system includes a positive displacement pump, such as a diaphragm pump, an electric motor directly coupled to the positive displacement pump, and a programmable controller configured to maintain a desired current to the electric motor.
• the programmable controller is adapted to sense the current to the motor and to maintain constant current.
• the controller may be a variable frequency drive controller. It has been found that constant current provides constant torque and constant torque achieves constant fluid discharge pressure from the pump.
• the programmable controller utilizes an absorbed power formula to determine the correct current to achieve the necessary torque for a desired fluid discharge pressure.
• the programmable controller includes a power saving mode with minimal current and the pump is "dead headed" with no flow. When demand resumes from the power saving mode, the programmable controller detects acceleration from the power saving mode and is operably configured to apply the desired current.
• the system is configured for connecting to an external application solely with a current connection to the motor and a fluid connection to the pump.
• a method for controlling the system includes programming the controller to control the system in a power saving mode with minimum current and torque with the pump having no flow. Using an absorbed power formula and setting a desired pump fluid discharge pressure, the current and torque requirements for the desired constant fluid pressure are determined. The controller then provides constant current to the motor corresponding to the torque for the desired constant fluid pressure. The controller maintains the current for the corresponding torque and fluid discharge pressure. The controller may be programmed to return the system to a power saving mode when demand ends. Moreover, as the torque automatically accelerates from the power saving mode when there is demand on the pump, the programmable controller senses the acceleration and returns to the current for the desired constant fluid discharge pressure.
• Figure 1 is a perspective view of a pump, motor and control system according to the principles of the present invention
• FIG. 2 is a flow diagram for operating the system shown in Figure 1;
• Figure 3 is a side sectional view of a diaphragm pump for the system shown in Figure 1 ;
• Figure 4 is a graph of torque versus current.
• the system (10) includes a positive displacement pump, such as a diaphragm pump (20).
• the pump is driven by an electric motor (12).
• An inverter (14) with a programmable logic controller (16) provides overall control of the system (10).
• the controller (16) may be a variable frequency drive controller. It can be appreciated that the system (10) is particularly suited for providing and maintaining constant fluid pressure.
• the components have a modular configuration and may be adapted to a larger fluid system and provides "plug and play" connections with such connections only needed for power for the motor (12) and liquid for the pump (20). Therefore, the system (10) of the present invention is easily adapted and retrofitted to existing systems. It can also be appreciated that the motor (12) may include forced cooling for advantageous operation. The system may be adapted to multiple different systems such as providing constant pressure for tools without requiring special modifications to the system receiving the pumped fluid.
• a positive displacement fluid pump such as a hydraulically driven diaphragm pump, generally designated (20).
• the diaphragm pump (20) is driven by a crankshaft (36) mounted in a crankcase (22).
• the manifold (26) includes an inlet passage (76) and a discharge passage (74).
• the manifold (26) also includes one or more inlet check valves (72) and one or more discharge check valves (70).
• the pump (20) is a diaphragm pump and includes a diaphragm (46) mounted on a valve stem (44).
• the diaphragm pump (20) may be a metering pump with very low flows that requires reliable precision inlet and discharge valves to achieve precise flow rates.
• the diaphragm (46) is hydraulically driven by a plunger (42) connected to a slider (40) on connecting rod (38) to the crankshaft (36).
• the diaphragm system includes an overfill check valve (48) and an underfill check valve (50).
• the diaphragm (46) receives fluid in a pumping chamber (34) and the fluid is pumped while the diaphragm deflects back and forth between an extended position and a fully retracted position.
• the manifold (26) includes separate inlet check valves (72) and discharge check valves (70).
• the torque at the pump shaft is controlled by motor current. Absorbed power formulas are utilized to measure the torque in relation to different electric currents. It has been found that the torque is directly proportional to the discharge pressure. Therefore, as torque is also linearly proportional to current, simple and reliable control is attained by providing a constant current to the motor (12), constant discharge fluid pressure may be achieved.
• achieving a constant discharge pressure may begin with the pump in a "dead headed" operating state. In such a mode, there is only a very small current provided and it is envisioned that the system (10) will require only 150 watts in this mode.
• the torque required and therefore the current required is calculated.
• the controller (16) applies the current to the motor (12) to drive the pump (20) at the desired torque to achieve the constant discharge fluid pressure.
• the logic controller (16) then maintains the proper current to achieve the fluid pressure.
• the programmable controller (16) again decreases the current so that a very slight trickle current is utilized.
• the present invention utilizes direct drive of the motor (12) to the pump (20) without a gearbox. Moreover, no pressure sensors are required after initial parameters and relationships are determined. The constant fluid pressure is maintained with simple operation of the programmable logic controller (12).
• the programmable logic controller (12) also provides for a metering/dosing control with different control software.
• the logic controller (12) is able to operate with the pump (20) dead headed, in which there is no flow, and is able to enter the sleep or power saving mode where current is reduced to a bare minimum for energy savings.
• the minimal torque causes an acceleration, which is automatically detected and torque is therefore again applied at the desired level by the controller (16).
• the controller (16) generally utilizes an absorbed power formula to set and maintain the motor (12) to drive the pump (20) to achieve the desired flow rate.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Control Of Positive-Displacement Pumps (AREA)
• Reciprocating Pumps (AREA)
• Control Of Electric Motors In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=60990826

Family Applications (1)

Country Status (7)

Families Citing this family (5)

Family Cites Families (13)

• 2017
  • 2017-09-15 CN CN201780070983.8A patent/CN111279077A/zh active Pending
  • 2017-09-15 CA CA3040627A patent/CA3040627A1/en not_active Abandoned
  • 2017-09-15 WO PCT/IB2017/001471 patent/WO2018051192A2/en unknown
  • 2017-09-15 RU RU2019111251A patent/RU2019111251A/ru not_active Application Discontinuation
  • 2017-09-15 US US15/706,374 patent/US20180080442A1/en not_active Abandoned
  • 2017-09-15 KR KR1020197010824A patent/KR20200019590A/ko unknown
  • 2017-09-15 EP EP17829686.9A patent/EP3513073A2/de not_active Withdrawn

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