Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
• • 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
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
  • F04C28/28—Safety arrangements; Monitoring
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D16/00—Control of fluid pressure
  • G05D16/20—Control of fluid pressure characterised by the use of electric means
  • G05D16/2006—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means
  • G05D16/208—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means using a combination of controlling means as defined in G05D16/2013 and G05D16/2066
• • 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
  • F04B2201/00—Pump parameters
  • F04B2201/12—Parameters of driving or driven means
  • F04B2201/1201—Rotational speed of the axis
• • 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
  • F04B2201/00—Pump parameters
  • F04B2201/12—Parameters of driving or driven means
  • F04B2201/1202—Torque on the axis
• • 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
• • 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
  • F04B2205/11—Outlet temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2270/00—Control; Monitoring or safety arrangements
  • F04C2270/03—Torque
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2270/00—Control; Monitoring or safety arrangements
  • F04C2270/05—Speed
  • F04C2270/052—Speed angular
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2270/00—Control; Monitoring or safety arrangements
  • F04C2270/18—Pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
  • F04C2270/00—Control; Monitoring or safety arrangements
  • F04C2270/19—Temperature

Definitions

• the invention relates to control apparatus and to a control method, for use particularly, though not exclusively, with compressors.
• compressors are well known. Although the invention has wide applications, it was specifically developed for use in preventing damage to compressors used in the discharge of product, for example liquid or particulate product, from a road vehicle tanker.
• the invention provides control apparatus for use with a fluid displacement device, the control apparatus comprising means to detect the temperature of fluid being displaced by the device, and means to control the device in dependence upon the sensed temperature.
• control means has means to preset at least one temperature control limit such that if fluid temperature rises above this limit, the apparatus operates to lower the working pressure.
• control apparatus may continue to monitor the temperature for a predetermined period before increasing the working pressure again.
• the control apparatus may have means to preset at least one pressure limit, the control apparatus being arranged to drop the pressure if the pressure rises above this limit.
• the control apparatus may be arranged to monitor pressure for a predetermined period.
• the apparatus may also be arranged to monitor the torque associated with a device being controlled by the apparatus.
• the apparatus may also be arranged to monitor the speed associated with a device being controlled by the apparatus.
• control apparatus may also be used with other fluid displacement devices such as pumps and blowers.
• control apparatus has a pressure relief valve movable between a closed position in which pressure is contained, and a relief position in which fluid can vent to reduce pressure.
• the pressure relief valve is solenoid operated.
• the control means may have means to receive an electric power supply, for example from a tanker vehicle.
• the power supply may be from 24 to 30 V DC.
• the control means may have means to receive an air supply, for example from a tanker vehicle.
• the air may be supplied at from 6 to 8 bar.
• the control means preferably has means to receive a temperature signal and a pressure signal.
• the control means preferably has a conduit to supply control air from the air supply to the pressure relief valve, under the control of the solenoid.
• the invention includes a method of controlling the pressure of a fluid comprising means to detect the temperature of the fluid and means to control the pressure of the fluid in dependence upon a sensed temperature.
• the pressure of the fluid is also sensed, a combination of temperature signals and pressure signals being utilised for control purposes.
• the invention includes a displacement device having control apparatus according to the invention.
• the invention also includes a tanker vehicle having control apparatus according to the invention.
• Figure 1 illustrates an embodiment of control apparatus according to the invention, including a pressure relief valve shown in cross-section and associated control means;
• Figure 2 is an internal view of the control means
• Figure 3 is a graph illustrating how the apparatus and method according to the invention might operate under one particular set of circumstances.
• control apparatus The basic components of the control apparatus are a pressure relief valve 10 and a control unit 11.
• the pressure relief valve 10 comprises a housing 12 in which there is slidingly and sealingly mounted a valve member having a head 13 and a shank 14.
• the housing 12 is connected by bolts 15 to a valve seat plate 16 having an aperture 17 therein.
• valve head 13 can be urged against the valve seat 16, to seal the aperture 17, by the application of pressure to an inlet 18 via a conduit 19.
• valve seat plate 16 is bolted to a component 20 at a location where the aperture 17 will be subject to the working pressure of the compressor to be controlled.
• the conduit 19 leads to the control unit 11.
• the control unit is also connected by a conduit 21 to a bore in the component 20 and the conduit 21 is connected to a pressure transducer 22 (see figure 2) to enable the compressor pressure to be monitored. This pressure is illustrated on a digital display 23.
• the control unit 11 is also capable of sensing the temperature of the compressed air via a lead 24. The temperature is displayed on a bar graph 25.
• a power supply 26 from a tanker vehicle (not shown) at 24 to 30 V DC.
• the same tanker vehicle provides an air supply 27 at 6 to 8 bar.
• the air supply conduit 27 and pressure supply conduit 19 are connected to a solenoid valve 28.
• the solenoid valve also has a vent 29.
• the solenoid valve 28 connects the air supply 27 to the conduit 19 so that air pressure forces the valve member 14 into the closed position shown in Figure 1. In this configuration, the vent 29 is closed by the solenoid valve.
• solenoid valve is movable to a second position in which the air supply 27 is closed and pressure vents from the valve via the conduit 19, solenoid valve, and solenoid vent 29.
• compressor pressure causes the valve head 13 to lift off the valve seat 16, relieving compressor pressure.
• the control unit 11 has also a SET button 30, an up SET POINT button 31 , a down SET POINT button 32, and lamps 33, 34 to warn an operator of a signal fault or a control fault respectively.
• Figure 3 illustrates graphically how the apparatus might operate under a particular set of circumstances. Temperature is measured in degrees centigrade on the left vertical axis 35. Pressure is measured in bar on the right vertical axis 36. Time is measured on the horizontal axis 37.
• Line 38 shows how pressure varies with time.
• Line 39 shows how temperature varies with time.
• the operator sets acceptable pressure limits at points 40 and 41. Acceptable temperature limits are set at points 42 and 43.
• the pressure control zone 44 illustrates an area in which some degree of pressure control is required, possibly because of a temporary blockage.
• Reference numeral 45 indicates a temperature control zone over which temperature control is exerted, because of an unexpected rise in temperature, for example caused by a faulty fan.
• the solenoid is actuated to reduce pressure. Pressure is dropped in steps of 0.1 bar until the temperature falls below the lower limit 42. Even then, the temperature is monitored over the period 46 to make sure that there is no recurrence before normal-operationis resumed.
• the limits 40, 41 , 42 and 43 are set using the buttons 31 and 32.
• the apparatus provides very sophisticated and sensitive control, which means that discharge from a tanker vehicle does not have to be continually monitored by an operator.
• control fault lamp If relief of pressure fails to rectify a situation, the control fault lamp is illuminated and a signal is sent to shut down the vehicle engine.
• the control unit can be arranged to log pressure, temperature and output states at regular intervals, for example one minute, during a period of operation, for example the most recent 16 hours of operation.
• the control unit can also store cumulative operation time for the compressor.
• the data is preferably stored in a non-volatile form available for download from a PC programme via a custom communication interface unit.
• the temperature display 25 may be arranged to flash as a single bar to indicate when limit 42 has been reached, display two flashing bars when limit 43 has been reached, and display three flashing bars to indicate that the temperature has reached a critical level and that engine shut-down is imminent.
• control unit stores the operating pressure which prevails when temperature reaches the lower limit 42.
• the control unit uses this as the upper pressure limit, instead of limit 41.
• the pressure control loop then continues as described above, with the displays indicating the severity of the problem. Failure to control the problem causes the engine to be shut off when the upper temperature limit 43 is reached.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Control Of Positive-Displacement Pumps (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9893255

Family Applications (1)

Country Status (8)

Families Citing this family (3)

Citations (6)

Family Cites Families (3)

• 2000
  • 2000-06-09 GB GBGB0014003.8A patent/GB0014003D0/en not_active Ceased
• 2001
  • 2001-05-16 WO PCT/GB2001/002154 patent/WO2001095048A1/en not_active Application Discontinuation
  • 2001-05-16 CA CA002412135A patent/CA2412135A1/en not_active Abandoned
  • 2001-05-16 AU AU2001258542A patent/AU2001258542A1/en not_active Abandoned
  • 2001-05-16 CZ CZ20024226A patent/CZ20024226A3/cs unknown
  • 2001-05-16 PL PL36230501A patent/PL362305A1/xx not_active Application Discontinuation
  • 2001-05-16 EP EP01931849A patent/EP1297399A1/en not_active Withdrawn
  • 2001-05-16 US US10/297,655 patent/US20040013530A1/en not_active Abandoned

Patent Citations (6)

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