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
  • F04B43/025—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms two or more plate-like pumping members in parallel
• • 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
  • F04B43/073—Pumps having fluid drive the actuating fluid being controlled by at least one valve
  • F04B43/0736—Pumps having fluid drive the actuating fluid being controlled by at least one valve with two or more pumping chambers in parallel
• • 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
  • F04B45/00—Pumps or pumping installations having flexible working members and specially adapted for elastic fluids
  • F04B45/04—Pumps or pumping installations having flexible working members and specially adapted for elastic fluids having plate-like flexible members, e.g. diaphragms
  • F04B45/043—Pumps or pumping installations having flexible working members and specially adapted for elastic fluids having plate-like flexible members, e.g. diaphragms two or more plate-like pumping flexible members in parallel
• • 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
  • F04B49/12—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 by varying the length of stroke of the working members
• • 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
  • F04B2203/10—Motor parameters of linear elastic fluid motors

Definitions

• the invention relates to pump apparatus and to the operation and control of the pump apparatus, and particularly but not exclusively to a pump control device and an air operated double diaphragm pump.
• Single diaphragm belt operated pumps can work at high pressures although they can be inefficient, large and can have difficulties conforming to current health and safety standards. If gas is present in the pumping media (for example as may occur with a leak or an insufficient seal) the pump can suffer vapour lock and can cease to operate.
• Air pumps are well known but are not commonly available for high pressure applications. Air pumps can have a single or double diaphragm design but their operation means the pump has air consumption higher than necessary for performing the pumping task alone. This is clearly inefficient and represents wasted energy.
• a diaphragm pump is defined as a positive displacement pump, most commonly a fluid pump.
• the diaphragm refers to a flexible sheet portion that moves in a reciprocating manner to provide pump action. Pumping is provided by the combination of the reciprocating action of one or more diaphragms (made for example of rubber, thermoplastic or teflon) and suitable valves either side of the diaphragm to pump a fluid.
• the one (or each) diaphragm is sealed with one side in the fluid to be pumped, and the other in air or hydraulic fluid.
• the diaphragm is flexed, causing the volume of the pump chamber to increase and decrease.
• a pair of non-return valves can be present to prevent and check any reverse flow of the fluid.
• the movement of the diaphragm can be effected by electromechanical means.
• Other diaphragm pumps can use unsealed diaphragms, which are flexed and therefore cause the volume to change.
• a pump control device for an air controlled double diaphragm pump, the pump comprising a pump housing, a pumping chamber within the housing, at least two diaphragms and a diaphragm coupling shaft, the diaphragms arranged within the chamber and operatively connected to the diaphragm coupling shaft, the control device comprising at least one ring magnet mounted within the diaphragm coupling shaft and a sensor apparatus, the sensor apparatus located within the pump housing and being arranged to detect the proximity of the at least one ring magnet and the diaphragm coupling shaft to the sensor apparatus, further comprising a programmable controller arranged to receive and respond to information from the sensor apparatus so as to control the end stroke and reciprocation of the coupling shaft.
• the pump control device operates in a double diaphragm pump using sensor apparatus to detect the position and proximity of a magnet mounted within the diaphragm coupling shaft.
• a programmable controller in the form of a Programmable Circuit Board (PCB) is responsive to the sensor apparatus and controls the direction of the diaphragms to switch them from one direction to the other and thus shuttle the diaphragm and cause the pump to operate.
• PCB Programmable Circuit Board
• AODD Air Operated Double Diaphragm
• the shuttling or switching of the diaphragms is switched with pressure applied to the back of the diaphragms to switch an integral air control valve and requires pressures of between 1 and 2 bar.
• Such high pressures are required to avoid pump stalling but are difficult to maintain and mean that the system is not energy efficient.
• the air consumption of the pump is higher than necessary to perform the pumping task alone. This is clearly undesirable and results in unnecessary cost and energy usage.
• the pressure is derived from the motive pressure delivered to the back of the diaphragms, and the volume of air is substantial in size, for example in a 2" diameter pump from Tapflo the volume is 2.3 litres, therefore if the application calls for the pump to run at say 0.5 bar, but has to peak at 1 .5 bar to switch the air control valve, 2.3 normal litres of compressed air is wasted every stoke. As the pump can stroke 3 times a second this therefore constitutes a large amount of wasted energy.
• the issue is common to all pumps with a single air supply and the improved control device addresses the aforementioned disadvantages.
• the dwell at the end of a pump stroke gives the pump a pulsed output which can be undesirable.
• control device comprises a pair of opposing ring magnets mounted within the diaphragm coupling shaft, and located in an arrangement having south terminals orientated facing the centre portion of the diaphragm coupling shaft.
• the south terminals facing the centre portion of the shaft can be aligned with detector apparatus within the pump housing and sensitive to the south terminals.
• the terminal to be detected is preferably arranged innermost such that the detection of the terminal to be detected allows full shuttle and travel of the diaphragm coupling shaft and thus fullest extent of the diaphragm.
• the pair of ring magnets are detected by the PCB and two south sensitive proximity switches are used. This provides some redundancy in the system and provides additional input for the sensor device.
• the sensor apparatus comprises at least one proximity sensor.
• the pump control of an embodiment could comprise a single proximity sensitive sensor, this would reduce the part count and the cost of the system. But may require a timing device for switching purposes.
• the sensor apparatus comprises 2 south pole sensitive proximity sensors. This provides a resilient sensor for detecting and sensing the presence and passing movement of the ring magnets mounted within the diaphragm coupling shaft.
• the controller in a preferred embodiment comprises a programmable circuit board (PCB) and programmable integrated controller (PIC) arranged to switch a solenoid operated air valve so as to control the direction of the diaphragms and coupling shaft.
• the controller is responsive to the sensor apparatus and thus the position of the diaphragm coupling shaft and the diaphragms connected to the shaft. The sensing is such that the position of the magnets in relation to the south pole sensitive proximity sensors is fed back to the PIC that in turns controls an external solenoid operated air valve.
• the solenoid valve in an embodiment is used directly to control airflow to the diaphragms so as to control the direction of the diaphragms in an embodiment. There may be more than one solenoid valve.
• a solenoid valve is arranged to pilot an air valve, the pilot air valve is provided to control the direction of the diaphragms and coupling shaft.
• the sensing of the diaphragm position and the activation of the air valve is not pressure dependent as it is controlled by detection of a magnetic field. No air from the pump itself is used or tapped and this means that there is no spike in the air pressure within the pump at the end of a stroke of the diaphragm coupling shaft. This means smoother operation and less wear and tear on the equipment due to pump activation.
• the controller is mounted within the pump housing and preferably the diaphragms are mounted directly to the pump body.
• a compact system is important for location within other equipment.
• a single seal is provided on the coupling shaft. There are no tapings required or air take offs from the pump cylinder housing so a single seal is sufficient.
• a single shaft seal is advantageous for reducing friction and allowing the system to run and operate at low pressures in both hydraulic and pneumatic applications.
• the apparatus can also be used in high pressure applications up to 40bar. The minimum operating pressure has been found in experiment to be 0.1 bar, and operation in the working example has been found to be of almost pulse free flow throughout the operating pressure range and the air consumption of the system is greatly reduced over a conventional AODD pump proving an equivalent flow.
• the movement of the shaft extends for up to 6 cm from the diaphragms.
• This allows for full movement of the diaphragm coupling shaft either side of the central location or rest position of the diaphragms and provides sufficient pump volume to be generated from the movement of the shaft and diaphragms.
• a pump comprising a pumping chamber, a double diaphragm and a pump control device as set out above.
• the pump is an Air Operated Double Diaphragm Pump.
• the operation is driven in the absence of compressed air and from one of the range; electrically, hydraulically. This is an efficient driving method.
• a method of operating and controlling an air double diaphragm pump comprising the steps of;
• the operation is achieved with activation of one solenoid valve changing states from On' to Off.
• two solenoid valves could be used, (here an initial stage would be with one solenoid valve Off and one On') and in use the states of the first and second valves would be reversed.
• methods of controlling and changing the direction of the diaphragms and coupling shaft are intended to be covered in this application.
• the pump control device can further comprise output means, which may comprise a display screen and/or a printer.
• Figure 1 is a vertical cross sectional view through a diaphragm pump with a pump control device in accordance with an embodiment of the present invention as seen from the first aspect;
• Figure 2 is a vertical cross sectional view of a portion of the diaphragm pump of Figure 1 ;
• Figure 3 is a side view of the controller and PCB apparatus in accordance with an embodiment of the present invention as seen from a first aspect
• Figure 4 is a flow diagram of a method for operating and controlling an AODD pump with a control device according to the present invention.
• the pump comprises a cylindrical housing 1 , a pumping chamber 2, a pump region 3 arranged to accommodate a volume of air, a diaphragm coupling shaft 4, and at least two diaphragms 5, 6.
• the diaphragms 5, 6, are operatively connected and mounted to the diaphragm coupling shaft 4 and are able to move under the action of the diaphragm coupling shaft 4.
• the diaphragms 5, 6 are mounted directly to the pump housing body.
• the shape of the diaphragms 5, 6, at rest, is such that they are parallel to each other.
• Input IN and output OUT ports are provided in the pump apparatus.
• the control device portion of the pump comprises ring magnets 10 and 12.
• the ring magnets in the illustrated embodiment are a pair of opposing ring magnets 10, 12 orientated with their south terminals facing the centre or innermost portion of the diaphragm coupling shaft 4.
• the ring magnets 10, 12 are located and mounted within the diaphragm coupling shaft 4 as illustrated in Figures 1 and 2.
• the sensor apparatus portion 14 of the control device is located in recess 16 within the pump housing 1 .
• the recess 16 accommodates the cables and wiring for the apparatus.
• the apparatus is connected to a power supply, solenoid switching valve, control and output devices (not shown).
• the sensor apparatus 14 comprises 2 south pole terminal sensitive proximity detectors.
• the control device further comprises is a controller (PCB) 18 and a Programmable Intergrated Controller (PIC) 20 operable to switch direction and operation of the diaphragm coupling shaft 4 and the diaphragms 5, 6.
• PCB controller
• PIC Programmable Intergrated Controller
• wear rings 30 are provided around the diaphragm coupling shaft 4 for smooth operation and movement.
• a single seal 40 Is provided between the inner pump housing 1 and the diaphragm coupling shaft 4.
• the sensor apparatus 14 housed and secured within the recess 16 picks up on and senses the position of the ring magnets.
• the scheme of operation is set out with reference to Figure 4 and steps 101 to 108.
• ring magnets 10 and the 12 mounted on diaphragm shaft 4 move in a direction back and to the right hand side of the view shown in Figures 1 and 2 they in turn pass the first proximity sensor and the position of the shaft 4 is noted.
• the second proximity sensor detects the ring magnets and acts by the functionality of the programmable controller to activate a solenoid valve to change the direction of movement of the shaft 4.
• the portion 14 features the back to back mounting of two south sensitive proximity switches as available commercially.
• the sensor switches act as set out above to detect the proximity of two opposing south facing ring magnets 10, 12 mounted within the diaphragm coupling shaft 4.
• the extent of the magnetic field in the example provided is around 25 to 30 mm, so the sensors are located within this range.
• the position of the magnets with in the pump and in relation to the sensors 14 is fed back to the PIC and the control program and firmware.
• the PIC in turn acts to operate an external solenoid operated air valve and to control the direction of the diaphragms.
• the PCB and PIC are held within a pocket and recess area within the pump housing 1 . Cables lead from the PCB to power supply and to the solenoid valve.
• the cable length can be up to 3 m.
• the dimensions of the PCB of the embodiment are 25 mm x 16 mm.
• the width of the proximity sensor region is 4 mm.
• the extent of the shuttle distance of the diaphragm coupling shaft is around 6cm.
• the switching and direction change is not pressure dependent, once the diaphragms 5, 6 and the diaphragm coupling shaft 4 has moved sufficiently for the ring magnet 10 or 12 to be so-called visible and detectable to the proximity sensor 14 it acts to change its state and send it in the opposite direction to the existing direction of travel. There is no spike in pressure at the end of a stroke of the diaphragm coupling shaft 4.
• the method of direction change is indirect and remote and does not require pressure tapings from within the pump chamber 2 or structural changes to the pump housing 1 . A single seal is required and this in turn reduces movement pressure and friction within the system.
• the pump can run and operate at very low pressure, compared with existing pump systems, around 0.1 bar, this represents a very low starting pressure for the system.
• the pump provides operation in a pulse free manner and thus without the need for a pulse damping device or retro fitted device to reduce pump discharge.
• a single seal is compatible with a hydraulic design and use with a hydraulic power supply pack (not shown).
• the pump has operated at pressures of up to 40 bar, flows up to 25 litres a minute and with a motor power rating as low as 90 watts.
• the external air control valve described in the example above is a commercially available externally piloted 5/2 solenoid/spring valve.
• the valve in this embodiment has control pressure and pump pressure connections, this means that the valve can be piloted at a higher pressure than the pressure of the pump.
• the higher pressure circuit is minimised to requiring just a few millilitres (ml_).
• the high pressure circuit does not therefore add significantly to the pressure required by the system and reduces the energy required by the system to the minimum, with overall operating pressures of 0.1 to 40 bar. Positive suction pressures of up to 18.5 bar can be withstood by the system.
• the output to the solenoid valve mentioned above is modulated to reduce further the energy consumption.
• modulation details of 50% duty after an initial spike it was found electrical power consumption reduced by 75%. A totally electric diaphragm pump can thus be achieved.
• the PCB and PIC firmware described has an output that can be utilised for further functionality, for example by a further control such as an external controller with additional components, for example a display or output screen.
• the pump and control may comprise any shape or orientation.
• the location of the control device portion and the ring magnets could be in a different position to that shown and described above.
• the positions of the sensors could be altered to take account of different magnetic field strength of different ring magnet combinations.
• Other types of magnet or other types of sensing system could be used.
• a greater or lesser distant of travel of diaphragm shaft could be envisaged.
• Alternative types or combinations of solenoid valves may be used.
• a totally hydraulic system without compressed air is also envisaged.
• This volume is substantial in size, for example in a 2" Tapflo pump is 2.3 litres, therefore if the application calls for the pump to run at say 0.5 bar, but has to peak at 1 .5 bar to switch the air control valve, 2.3 normal litres of compressed air is wasted every stoke. As the pump can stroke 3 times a second constitutes a massive amount of wasted energy.
• This dwell at the end of stroke also gives the pump a pulsed output as no flow occurs whilst the pressure builds to switch the valve.
• AODD Air Operated Double Diaphragm
• the single seal method allows for hydraulic operation, thus giving an electrically operated double diaphragm pump with all the qualities of an air operated pump without the use of compressed air.
• the PCB incorporates two south sensitive proximity switches (data sheets available) mounted back to back that detect the proximity of two opposing south facing ring magnets mounted within the diaphragm coupling shaft. The position of the magnets in relation to the sensors is fed back into the PIC firmware that in turn controls an external solenoid operated air valve that in turn control the direction of the diaphragms. See TPUK 00216 & 00217 below.
• This method of sensing the diaphragms position is not pressure dependant, once the diaphragm has moved sufficiently for the magnet to be visible to the proximity sensor it changes its state and sends the diaphragm in the opposite direction towards the opposing sensor and so on. Therefore there is no spike in pressure at the end of stroke.
• this method is indirect it does not require any pressure tapings from within the pump, therefore we only need one main seal, thus the friction is significantly reduced and the pump can run at very low pressure circa 0.1 bar, which is unique in the market.
• the single seal was selected for both pneumatic and hydraulic applications, so the design was suitable for the high pressure application as the means of switching the control valve on a hydraulic power pack. This has been tested at pressures up to 40 bar, and flows of up to 25 l/min, at motor ratings as low as 90 watts. This also appears unique in the market. As the position sensing is indirect removing the end of stroke pulse the resultant flow from a diaphragm pump using the LEAP technology is practically pulse free. Pulses are common to all AODD pumps so there are a number of pulsation dampeners available on the market that are retro fitted to the discharge of AODD pumps to reduce the pulsing. The need for a complimentary dampener is eradicated using LEAP technology.
• the external air control valve is an externally piloted 5/2 solenoid/spring valve (available from a variety of manufacturers). By having a control pressure and a pump pressure connection the valve can be piloted at a higher pressure than the pump. The higher pressure circuit is minimised to a few mL reducing the energy required to the bear minimum. Therefore the pump can be operated at any pressure from 0.1 to 40 bar.
• the output to the solenoid valve is modulated to minimise energy consumption still further. Especially important on the hydraulically driven pumps as the control valve coil wattage is circa 30 watts. By modulating at 50% duty after an initial spike the electrical power consumption is reduced by a further 75%.
• the PCB/firmware has an output that can be used by an external control system such as a PLC to offer additional control features. This would normally require an additional component, but is incorporated in the LEAP design.
• Hydraulic operation can be started/stopped by turning the power pack supply on/off.

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• 2013
  • 2013-09-20 GB GB1316750.7A patent/GB2518411B/en active Active
• 2014
  • 2014-09-18 EP EP14772199.7A patent/EP3047149A1/de not_active Withdrawn
  • 2014-09-18 WO PCT/GB2014/052839 patent/WO2015040404A1/en active Application Filing

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