Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05C—ELECTRIC CIRCUITS OR APPARATUS SPECIALLY DESIGNED FOR USE IN EQUIPMENT FOR KILLING, STUNNING, OR GUIDING LIVING BEINGS
  • H05C1/00—Circuits or apparatus for generating electric shock effects
  • H05C1/04—Circuits or apparatus for generating electric shock effects providing pulse voltages

Definitions

• Tetanus is physiologically described as a condition of a muscle which is in a state of persistent continuous contraction. If this condition exists for any extended period the fish would be paralyzed and may even die.
• U.S. Patent 1,974,444 by Burkey he discloses that a short pulse of current, and a longer interval for them to recover will stop the fish but not produce tetanus. This reference also teaches that the higher the voltage, the slower the interruptions may be.
• U.S. Patent 2,605,742 by Burkey it is disclosed that the optimum waveform involves a short spike at four to eight pulses per second. This pulse is produced by discharging condensers from about 800 volts.
• U.S. Patent 5,327,854 by Smith extends John C. Lilly's optimal waveform to delivering minimal injury to fish.
• U.S. Patent 5,445,111 by Smith et al introduces a microprocessor controlled fish shocking device. Special materials, such as expensive stainless steel, are recommended by the California Department of Fish and Game in prior fish screens in order to avoid corrosion. They also suggest other Corrosion protection.
• the barrier type has to be at least 27% open and needs cleaning. These requirements impede water flow and increase the cost to operate.
• Power supplies for charging capacitors and networks have usually used Past charging to the required voltage, with a flat top, until the discharge took place.
• Current mode supplies are usually modified to be voltage controlled so the voltage can be monitored continuously.
• the unified power factor correction, PFC involves all the power switching elements. The advantages of unified PFC or the use of cascade elements with low drive requirements have not been used in these applications.
• the high switching frequency for DC to DC conversion allows small efficient high frequency transformers to be used. Multiple flybacks provide higher power and higher frequencies for filtering with low cost relays.
• the application in oil wells involves steaming at the strata.
• the usual method is to steam from the surface which involves great loss of heat if the well is deep. Attempts have been made to reach the desired level with other techniques.
• the heater also has non insulated electrodes to avoid problems with water content.
• This invention combines steaming with a lowering of the viscosity of the oil by pulsing with a fast rise time. Other materials can be treated as well as the electrodes.
• Hans Conrad teaches that processes exist which permeate the whole object. Patents which cover plasma treated materials such as patent #5,473,165 by Stinnett et al. and their article on Surface Treatment by Pulsed Ion Beams claim just the surface.
• the present invention has a fish screen as it's primary load.
• the power supply, PS is a constant power device.
• Power factor correction, PFC is integrated into the switcher rather than using an add on. Multiple relays at high frequencies allows the use of slow devices.
• the time of charging the pulse forming networks is regulated so that it draws power during the whole cycle. This lowers the line current.
• the fish screen utilizes a magnetic field for the first time in publication. It was noted in operation that special materials such as copper did not have to be chosen to avoid corrosion. This feature has been studied and used. Other materials have been tried in special electrolytes and the effects permeate the whole specimen. Impurities, hardness, and crystal structure are all affected as shown by an x-ray pole figure analysis.
• the down hole application in oil wells permits placing a heater at a desired strata and thinning the oil, by pulsing, in secondary recovery.
• Use at 4,160, a standard voltage, for down-hole applications needs a revision of the voltage dependent parts in the control.
• Fig 1A is a schematic diagram of the power supply control.
• Fig IB is a schematic diagram of the power supply output.
• Fig 2 shows the power supply with a fish screen load.
• Fig 3 shows the fish screen element as material treated by the fish screen power supply.
• Fig 4 shows a down hole application in an oil well.
• All parts except the programmed programmable logic device PLD can be obtained from several sources. These include Allied Electronics, Digikey, Mouser, and Westcode. Transformer Ta, snubber Uj , and pulse forming networks, Un, and Up must be designed for the application. Standard design techniques can be found in the references .
• the start of the transformer windings have dots.
• Fig 1 shows a FS fed by the preferred embodiment of a PS.
• the symbols + and — indicate the two screens and magnet M is shown in a horizontal position.
• the load is a fish screen the normal operation is for electrical pulses to travel between the screen and ground or another screen.
• a slow rate of pulses is found to be optimum for some species.
• a magnetic field will alert migrant fish between pulses. They will learn that a pulse may come.
• This screen is unique in that no one discussing fish screens has mentioned using magnetic fields. They can be combined with electric fields. Migratory fish must distinguish the earth's field from the sun's as they are almost equal. They can be led to fish ladders as the fish go down the stream. Fish will learn the correct way to get to the hatchery and avoid the bends when they go over a high dam.
• Fig 2 shows a load where the control output can be several thousand volts down hole in an oil well.
• Enhanced Oil Recovery by Latil et al . (1980) indicate earlier methods. It may be lowered to the desired strata to steam and lower the viscosity of the oil. There will be little loss of heat. If the frequency is raised the pulses will change the molecular structure of the oil. The thinner oil will be easier to pump. A rise time of under 20 microseconds increases the speed of this process .
• Fig 3 shows a load where an object is subjected to the pulsing of a PS. It was noted that there was little corrosion of the part of the fish screen in the water. This was investigated further and found to be a change in the material which penetrated throughout the part. Pole figure analysis has been done on treated parts confirming this. It has also been found that the di/dt of the discharge was important and the necessary plasma in the solution occurred faster with a peak at 10 ⁇ seconds than the original 20 ⁇ seconds.
• Fig 3 also shows a load incorporating a material in an electrolyte.
• the pulses will create a plasma which can remove impurities and make the crystal structure more uniform throughout the material as shown by its pole figure. This will delay corrosion of the pipes used in the fish screen.
• Patent #5,473,165 (1995) and Surface Treatment With Pulsed Ion Beams, by Stinnett, et al. (1992) indicate treatment which changes surface characteristics. This also applies to that of fig 2. None of these claims the complete penetration of the present invention.
• Fig 4A shows the control section COa of the power supply PS. This feeds an output section Oa, shown in Fig 4B, with a direct current link between them.
• the output section incorporates pulse forming networks to form trapezoidal pulses. These have more energy in the high voltage peak than a simple capacitor discharge as the pulse is squarer.
• the electrolyte load has a small voltage across it while charging, compared to the discharge voltage.
• a conventional input, Ua where A and G are be fed from a source of AC or DC electric power. It may use a RFI filter, switch, surge suppressor, and a bridge rectifier to provide the main output voltage. Regulated low power voltages are provided for control. A reference voltage is shown which is compared with a fraction of the output voltage by comparator Ub.
• Ua are three flyback PS in this embodiment which consist of transformer, Ta, turn off snubber Uj , high and low voltage relays Ka, Kb.
• the inductance in Ta tends to maintain the current through them and produce a high voltage, as in a spark coil, when Kb turns off.
• the outputs from Ta charge a pulse forming network Up, through diode, Df .
• the relay Ka, Kb, and Kc are MOSFETs or IGBTs in the preferred embodiment however they can be other devices including tubes for high power loads .
• Filter capacitor Ca only filters 3 times 40Khz so it is small. The low frequency ripple left in the output is no problem in this application.
• the current in the low voltage relay Kb is monitored by resistors Rn and Rm resulting in current sense Ic.
• the diode Dg from the junctions of the current sense resistor to the outputs of PLD, Ue hold down the current sense when relay Kb are turned off.
• Resistor Rr holds the positive end of Kb at the voltage of Zener Dk when Kb turns off Ka.
• Output voltage Vc is compared with reference Vr by comparator Ub and changes PLD Ue pin 17 to low if the required output voltage is reached before Kc discharges. Capacitor Ch makes this change take several cycles of the low frequency. This yields a constant current during charging.
• Comparator Ub compares Iw and relay current, Ic and speeds up the high frequency oscillator in Schmitt trigger, Uf if it is larger than Iw.
• the increased frequency allows transformer, Ta less current to build up in Ka and Kb. Then the current follows the variation in resistor Ra from the bridge in input, Ua.
• the fast correction in current reference, Ir gives PFC. Said correction is now required in Europe and will be elsewhere.
• the slow change in timer multiplier, I determines the charging time.
• the output load may need a DC link from the input if the load is a fish screen or in a down hole application.
• Transmitter Uk and receiver Um provide a DC link using RS485 or RF techniques.
• the DC link allows the charging current to be sent to the output which is normally much lower than the discharge current permitting smaller wire.
• RF transmission requires fewer wires and permits an easier change in polarity for drivers.
• RF also allows power to be sent to the drivers. It requires one coaxial cable for both high voltage and control . Remote control as used in model aircraft can be used for complex systems.
• the driver for relay, Kc uses a constant current generator to generate a pulse for the start of switching so it uses a low voltage .
• the output from Kc has a saturating choke La to delay firing until after the wafer is fully excited from the driver.
• Patent #5,442,539 by Slobodon CuK, Aug. 17 1995 describes a PS with PFC and follows a long chain of his patents.
• the major use of flyback PSs has been in television sets.
• a description of their properties are in Power Electronics by Mohan et al.
• the design technique is shown in Simplified Design of Switching Power Supplies by Lenk (1995). Pulse forming networks are well

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Citations (6)

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• 1997
  • 1997-12-23 EP EP97953542A patent/EP1013154A4/de not_active Withdrawn
  • 1997-12-23 WO PCT/US1997/024165 patent/WO1998028970A2/en not_active Application Discontinuation

Patent Citations (6)

Non-Patent Citations (1)

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