Safety recovery system of volatile material
7 claims: 5 independent, 2 dependent
- 1Patentkrav 1. System för säker återvinning av ånga, speciellt vid bränslepåfyllningsanläggningar innefattande en ledning för återförande av ånga-luftblandningen från pumpmunstycket till anläggningens under jord belägna tank, en pump driven av en elektrisk motor för insugning av nämnda blandning, en ventilator som sammanbinder botten av den underjordiska tanken med atmosfären, en ledning för överförande av över skottsånga från den underjordiska tankens dom till en ångkondensationsenhet och en återledning från nämnda enhet till domen för den kondenserande ångan, kännetecknad av att nämnda returledning för ånga-luftblandningen är försedd med en backventil nedströms pumpen och är ansluten till nämnda ventilator, som når till botten på anläggningens underjordiska tank och som är försedd med en kontrollventil mot atmosfären, varvid pumpen som verkar på returledningen är en positiv deplacementpump, vars elektriska motor är styrd av medel, vilka reglerar dess rotationshastighet ögonblick för ögonblick, som en funktion av den volumetriska material mängden utmatat bränsle, med beaktande av tryckfall, med ett eventuellt överskott av luft beroende på temperaturerna hos den underjordiska tanken och hos ång-luftblandningen, och med kontinuerlig mätning av den effektiva densiteten hos nämnda blandning och jämförande av denna med åtminstone ett begränsande värde som indikerar en blandning som är mycket utspädd med luft och därför är explosiv, varvid medel också är anordnade för förhindrande och/eller begränsande spridning av explosionen och för att säkerställa att ånga-luftblandningen i nämnda returledning är turbulent uppströms den positiva deplacementpumpen.
- 2System för säker återvinning av ånga i enlighet med krav 1, kännetecknad av att medlen för att förhindra och/eller begränsa spridningen av explosionen består av två flamfällor inplacerade en i ångreturledningen i pumpmunstycket och en nedströms den positiva deplacementpumpen, och av förlängning av returledningen från ångkondensationsenheten så långt som till botten av anläggningens underjordiska tank, varvid även en sugpump är anordnad.
- 3System för återvinning av ånga i enlighet med krav 1, k ä η n e tecknad av att medlen för reglering ögonblick för ögonblick av rotationshastigheten hos den elektriska motorn tillhörande den positiva deplacementsugpumpen för ånga-luftblandningen består av ett minnesregister i vilket värdena för ångtryck, som en funktion av temperaturen Pv(T) för det använda 501 007 bränslet är lagrade, till vars ingångar matas de uppmätta värdena Tc för det utmatade bränslet och Tm för ånga-luftblandningen, och vars utgångar är anslutna till en beräkningsenhet, till vilken de uppmätta värdena för atmosfäriskt tryck Po och för nämnda temperaturer Tc och Tm matas;utdata från nämnda beräkningsenhet, vilken beräknar de ingående data i enlighet med uttrycket 1 + Po-Pv(Tc) , Tm Po-Pv(Tm) Po Tc Po därefter matas till en komparator vilken jämför värdet med 1, och om det är mindre än 1 sätter det lika med 1 medan i andra fall det lämnas oförändrat, varvid utdata från nämnda komparator matas till en multiplikatorenhet till vilken också matas den uppmätta volumetriska materialmängden bränsle Qc som utmatats och utdata från en ytterligare beräkningsenhet vilken beräknar termen pj^p» varvid denna enhet matas med de uppmätta värdena för atmosfäriskt tryck Po och för tryckfallet Ap för ånga-luftblandningen mätt vid inloppet till den positiva deplacementpumpen;ett ytterligare minnesregister, i vilket de temperaturbaserade begränsande densitetsvärdena _fl och 2 finns lagrade, matas med den uppmätta temperaturen Tm varvid dess utgångar är anslutna till en tredje beräkningsenhet till vilken utgången från en andra multiplikatorenhet är ansluten, till vars ingångar matas utdata från ett minnesregister i vilket de experimentella värdena för K som en funktion av temperaturen är lagrade och till vars ingång matas nämnda Tm, och utdata från en ytterligare beräkningsenhet vars ingångar matas med nämnda tryckfall Δρ och med feedback-utdata från den elektriska motorn, vilket ger den aktuella rotationshastigheten hos motorn, varvid beräkningsenheten bearbetar indata i enlighet med uttrycket Δ p a /v^, varvid utdata från nämnda tredje beräkningsenhet som bestämmer termen ,ί. 1 därefter matas till en komparator av vilken lämnas oförändrad om den ligger mellan 0 och 1, sätts lika med 1 om den är större än 1, och sätts lika med 0 om den är mindre än 0 varvid komparatorn simultant ger en utsignal för avstängning av bränsleutmatning;varvid utdata från denna senare komparator matas till multiplikatorenheten, vars utgång är ansluten till en dividerare för att dividera med den kända slagvolymen C hos den positiva deplacementpumpen som används, så att dess utdata representerar den optimala pumprotationshastigheten vilken slutligen matas, tillsammans med nämnda feedback-utdata från 501 007 den elektriska motorn, till ingången hos en PID-kontroller, vars utdata ger effekt till nämnda elektriska motor via en vridmoment-strömomvandlare.
- 4System för säker återvinning av ånga i enlighet med något av föregående krav, kännetecknat av att nämnda medel för att säkerställa turbulent rörelse hos ånga-luftblandningen i nämnda returledning uppströms den positiva deplacementpumpen består av ett spiralelement infört i nämnda returledning uppströms pumpen.
- 5System för säker återvinning av ånga i enlighet med något av föregående krav, kännetecknat av att nämnda medel för att tillförsäkra turbulent rörelse hos ånga-luftblandningen i nämnda returledning uppströms den positiva deplacementpumpen består av granulärt material som genom limning fästs vid returledningens inre vägg, uppströms pumpen.
- 6System för säker återvinning av ånga enligt ett av de föregående kraven, kännetecknat av att nämnda medel för säkerställande av turbulent rörelse hos ånga-luftblandningen i nämnda returledning uppströms den positiva deplacementpumpen innefattar att ledningens inre vägg gjorts skrovlig genom mekanisk bearbetning eller kemisk påverkan.
- 7System för säker återvinning av ånga i enlighet med något av föregående krav, kännetecknat av att medlen för att säkerställa turbulent rörelse hos ånga-luftblandningen i nämnda returledning uppströms den positiva deplacementpumpen är anordnade i den del av returledningen som ligger inom själva pumpmunstycket, varvid denna del uppvisar ett tvärsnitt som är väsentligen mindre än tvärsnittet hos resten av returledningen. 501 007 501 007 cq σ • U-
Independent claims7
87 paragraphs in 2 sections, as filed
SWEDEN (12) PATENT (13) C2 (11)
501 007 (19) SE
<img file="SE501007C2_D0001.tif" />
(51) International class <sup>5 </sup>B67D 5/06 // B67D 5/32
PATENT AND REGISTRATION (45) Patent granted (41) Application widely available (22) Patent application received (24) Maturity date (62) Number of application (33) International Filing day (86) Filing date for European patent application (83) Deposit of microorganism
1994-10-17
1990-07-05
1989-12-28
1989-12-28 (21) Patent Application Number 3904339.7
Application received as:
χΐ Swedish patent application completed international patent application - with number □ European patent application converted with number (30)
89-01-04 IT 19016/89 (73) PATENTHAVARE Nuovopignone Industry Meccaniche e Fonderia SpA,
<td></td><td>Florence IT</td>
<td>(72) INVENTOR (74) AGENT (54) NAME</td><td>Giorgio Bergamini, Bari IT, Ernesto Paris, Bari IT AB Dahl's patent office Systems for the safe recovery of steam, especially at refueling plants</td>
(56) PUBLISHED QUOTES: - - - (57) SUMMARY: System for safe steam recovery, especially for fuel refueling <sup>An</sup>pipes in which a positive displacement pump performs controlled steam-air mixture suction in a steam return line extending to the bottom of the plant's underground tank, and provided with a check valve downstream of the pump; a special circuit is also provided for performing said controlled suction based on the amount of fuel discharged, on the difference in temperature between the underground tank and the recovered mixture, and in particular on the density of the mixture by which the degree of explosion propensity of the mixture is determined; finally, means are provided to prevent or limit the spread of explosion.
<img file="SE501007C2_D0002.tif" />
The numbers in brackets indicate international identification code, INID code. Letters in clamps indicate international document code.
501 007
The invention relates to a new vapor recovery system, especially suitable for fuel filling plants, which not only ensures efficient, safe and total recovery without the need for bellows-like sealing elements, but which, taking into account the danger of explosions, allows maximum intrinsic safety with respect to the formation of explosive mixtures at all times. and which can also operate under critical conditions, at all times it is equipped with adequate devices for preventing explosion propagation.
Steam recovery systems at fuel refueling plants are already known in the prior art, essentially comprising bellows-like elements whose purpose is to form a seal between the pump nozzle and the fuel refueling tube of the vehicles to be refueled, along with additional tubes, which leads from the judgment of the underground tank at the fuel refill plant to said motor vehicle tank to recover the steam from the latter with or without the aid of a suction pump.
However, such known systems exhibit a number of disadvantages, the most important being the critical hermetic seal which must be arranged between said bellows, which necessitates precise and relatively workable adjustments and continuous maintenance.
In this regard, if the bellows do not form a perfect seal, not only does a substantial reduction in system efficiency because not all steam is withdrawn, but also uncertain safety conditions, especially if a vapor suction pump is used, because then any uncontrolled air entrainment could dilute the vapor-air mixture too much, which, as is well known, could cause a critical explosion zone. In order to cope with this difficulty, known delivery guns have been provided with a device for switching off the gas supply if the seal is not perfect (no seal, no flow), but such devices have not met the user's understanding, especially the tank self-stations, where there are tendencies to damage connection, which causes inefficiency and danger in the system.
A further disadvantage of known systems is the difficulty of supplying the tank installed below ground, which has a lower temperature than the vehicle's fuel tank, the specific amount of air necessary to compensate for the reduction in volume of the recovered steam, which is determined by the lower local temperature. which could result in vacuum in it
501 007 below the ground of the tank and which, although normal and does not constitute a dangerous condition in plants without steam recovery, becomes very dangerous in known plants including recycling where the recycling circuits lead directly into the underground tank's judgment, due to the possibly repeated and uncontrolled the absorption of air due to defects in the seal, leading to the aforementioned consequences.
A further disadvantage is the fact that in the known recycling systems that use suction pumps or injectors, possibly excess suction, not only generate the aforementioned explosion hazards but can also generate pressure in the underground tanks, which is detrimental for the protection of the environment due to of possible leakage from the tanks.
The object of the present invention is to overcome said disadvantages by providing a system for the safe recovery of steam, especially suitable for fuel refilling plants, which do not use any type of bellows sealing elements and which enable efficient and total steam recovery without the risk of explosion or undesirable earth pressure under the tank. .
This is achieved essentially by the return line for the recovered steam-air mixture no longer feeding the mixture into the underground tank's judgment, but instead at the bottom of the tank from which the mixture bubbles up through the fuel and into the dome, providing controlled suction of the steam-air mixture. by a positive displacement pump, whose speed is continuously controlled on the basis of the volumetric amount of material delivered, to draw in a volumetric amount of steam-air mixture equal to the volumetric amount of fuel delivered plus any excess air depending on the temperature of the two tanks, continuously comparing the density of the withdrawn mixture with at least a limiting value indicating a very dilute and thus explosive mixture.
In this way, by bubbling the recovered steam-air mixture through the fuel, the temperature is quickly adjusted to the temperature of the underground tank, resulting in its rapid volumetric adjustment, thereby allowing a larger volume of volume to be withdrawn than the quantity delivered, which is especially needed when has underground tanks with a lower temperature than the recycled mixture. In addition, an extension of the return pipe to the bottom of the underground tank means that the pressure in this pipe is always positive, thereby preventing all possibilities of
501 007
IN <sub>+</sub> Po-Pv (Tc). Tm _ Po-Pv (Tm) /. Po Tc Po J
Qm = Qc undesirable infiltration of air from outside and possible pressure of the tank dam.
The use of a positive displacement suction pump makes it easy to retract the necessary specific volumetric quantity mixture. In this regard, it can be shown analytically that the volumetric amount of Qm can be expressed by the following relation:
RDs:
Qc corresponds to the volumetric amount of fuel delivered;
Po corresponds to the measured atmospheric pressure;
Δ p corresponds to the pressure drop of the vapor-air mixture measured at the inlet of the positive displacement pump;
Tc corresponds to the measured temperature of the fuel to be delivered, which in practice corresponds to the temperature of the steam-air mixture present in the underground tank of the filling plant;
Tm corresponds to the measured temperature of the vapor-air mixture drawn through the pump nozzle;
Pv (Tc) corresponds to the characteristic vapor pressure of the fuel at temperature Tc; Pv (Tm) corresponds to the characteristic vapor pressure of the fuel at the temperature T m;
represents the density of the vapor-air mixture;
and f 2 corresponds to temperature-based limit values which define the density range within which the volumetric amount of Qm must be gradually reduced to zero to avoid any danger of explosion from a mixture too diluted with air.
In the formula, the first term within squeeze shows the excess amount of air to be drawn in to compensate for the volume reduction which is due to the temperature of the underground tank being lower than the temperature of the mixture to be recovered. This is true only for Tm> Tc, while for Tm <Tc this is set equal to 1. The second term within clamps indicates whether the mixture is dangerous due to being too diluted, so that the volumetric amount of Qm must be reduced; this is true only for £ 2 <<gl, while for ζ>> 1 it is set equal to and for p <2 is set equal to 0.
in
Po-4p
501 007
This term therefore allows the system to be protected even in the event of improper handling during dispensing, such as extraction of the pump nozzle from the vehicle's fuel refill pipe during refilling, or if faults or special devices are present in the structure of the vehicle tank. From the aforementioned it is also clear that fuel dispensing can easily be turned off in all non-normal cases which involves excess dilution of the mixture.
Finally, the last term is the pressure drop of the mixture drawn into the return line from the pump nozzle at the entrance to the positive displacement pump, which is used to obtain the mixture density.
In this regard, the density is calculated using an empirical formula of the type:
<img file="SE501007C2_D0003.tif" />
where v indicates the velocity of the mixture in the return line, which is substantially proportional to the rotational speed n of the positive displacement pump, K (T) is a variable which is a function of temperature and type of fuel used, 21 p is said pressure drop, and exponents a and b constitute experimentally obtained values, which depend on the geometry and roughness of the return pipe, calculated from the intake point to the suction pump; this pipeline must be such that in all cases it is ensured that the movement of the withdrawn mixture is turbulent, while this is an essential condition for the validity of the formula (2).
For this purpose, according to a characteristic feature of the present invention, said conduit is provided in its interior either with an inserted spiral element or with granules glued to the inner wall, or its interior is machined or chemically attacked to provide roughness on said conduit. wall and thereby create substantial roughness of the wall and thus cause high turbulent movement.
Again in accordance with the present embodiment of the present invention, said roughness of the wall is achieved and concentrated in the rigid metal part of the return line at the pump nozzle, which has also been given a substantially smaller cross-section than the rest of the line, which is in the form of a rubber hose and therefore does not have a constant geometry.
501 007
In this way, said pressure drop in the return line from the pump nozzle to the inlet of the positive depletion pump is substantially concentrated to said portion, which exhibits a stable and solid mechanical geometry, allowing an efficient and repeatable measurement of said pressure drop, this measurement ensuring the safety of the system, accurate and repeatable evaluation of the density of the steam-air mixture withdrawn.
In order for the system to function safely, the device can be set with K (T) values obtained experimentally once and for all time, either using a summer fuel, ie. one which gives a calculated value which is always lower than or equal to the correct value and thus activates the protection against excessive mixing dilution before the hazardous state is achieved, or a winter fuel which gives lower K (T) values, where in this case ξ 1 The (T) and £ 2 (T) values are increased by a suitable margin, especially for temperatures exceeding 0 ° C.
This second procedure allows operation with greater precision at lower temperatures and with winter gasoline when the margins for variations in density around the limits of any explosion are small, and where the previous procedure would quickly lead to a shutdown of the suction.
It is obvious that if the positive displacement cement pump drive motor is rotated at a rotational speed n given by where C is the stroke volume of the pump, the pump will always draw in the optimum necessary volumetric amount.
Thus, the system for safe vapor recovery, especially for fuel refill systems, includes a conduit for returning the vapor-air mixture from the pump nozzle to the plant's underground tank, a pump operated by an electric motor for suctioning said mixture, a fan connecting the bottom portion of the underground tank, a conduit for transferring excess steam from the condenser steam condenser to a steam condensing unit and a return conduit from said condenser to the condensed steam condenser, characterized in accordance with the present invention that the steam-air mixing conduit is provided with a check valve downstream of the pump; and is connected to the fan which extends from the bottom of the underground tank and is provided with a
501 007 control valve against the atmosphere, wherein the suction pump acting on said return line is a positive displacement pump, whose electric motor is controlled by means which regulate its speed of rotation moment by moment as a function of the volumetric amount of fuel discharged, taking into account pressure drop, with a possible excess of air depending on the temperatures of the underground tank and the vapor-air mixture, and continuously measuring the effective density of said mixture and comparing it with a limiting value indicating a mixture which is highly diluted with air and which is therefore explosive, wherein means are also provided to prevent and / or limit the spread of the explosion and to ensure that the vapor-air mixture in said return line is turbulent above said positive displacement pump.
In accordance with a further feature of the present invention, said means for preventing and / or limiting the spread of the explosion consists of two flame traps inserted into the steam return manifold of the pump nozzle and a positive displacement pump below said, and of extending said return line from the steam condensing unit to the bottom. in the underground tank of the plant, and also to supply it with an intake pump.
In this way, any explosion over the pump cannot propagate downstream of the pump where the pipes are under positive pressure, or into the vehicle tank being filled, the bubbling of the recovered steam from the condensing unit into the fuel in the underground tank at the latter's temperature. , and thus without cooling the steam, protects the recovery operation from any explosion hazard.
A further feature of the present invention is that said means for controlling the rate of rotation of the electric motor associated with the instantaneous displacement suction pump instantaneous vapor-air mixture consists of a memory register in which the vapor pressure values as a function of the temperature Pv (T) have the fuel. stored, to whose inputs are fed the measured values of temperature Tc on the discharged fuel and temperature of the steam-air mixture Tm, and whose outputs are connected to an operating unit to which the measured values of the atmospheric pressure Po and of said temperatures Tc and Tm are input; wherein output from said operating unit which processes input in accordance with the expression
501 007
<td></td><td>7 η</td>
<td> 1 <sub>(</sub> Po-Pv (Tc). tm</td><td>Po Pv (Tm)</td>
Po Tc Po is then fed to a comparator that compares this value to 1, and if the value is less than 1 sets it equal to 1, while in other cases it is left unchanged, the output of said comparator being fed to a multiplication unit to which the measured volumetric quantities of discharged fuel Qc and the output of another operating unit which calculates the Po term p<sub>O</sub>whereby the measured atmospheric pressure Po and the pressure drop Δ p of the steam-air mixture measured at the inlet to the positive displacement pump are fed to the input of this unit; a further memory register in which the temperature-based boundary density values £ 1 and J> 2 are stored, which is fed with the measured temperature Tm and its output connected to a third operating unit to which the output of a second multiplication unit is connected, to which the inputs are output from a memory register in which the experimental values of K, as a function of temperature, are stored and whose input is fed with said Tm, and the output of a further operating unit whose inputs are fed with said pressure drop p and with feedback data from the electric motor, which provides the effective rotational speed of the motor, said operating unit processing input data in accordance with a <sub>D</sub>a hot with the expression -g, wherein the output of the third operating unit that determines the term is then fed to a comparator in which it remains unchanged if it is between 0 and 1, set equal to 1 if greater than 1, and set equal to 0 if is less than 0 wherein the comparator also provides an output for shut off fuel output; the output of this latter comparator being fed to the multiplication unit whose output is connected to a divider for division with the known stroke (cylinder displacement) of the positive displacement pump, so that the output corresponds to the optimal pump rotation speed which is finally fed, together with said feedback data from the electric motor, to the input of a PLC controller whose output is fed to the electric motor via a torque converter.
This, therefore, ensures that the output of said multiplication unit provides the expression (1) in which the density j is precisely determined by the expression (2), so that the real rotational speed of the motor is compared with the optimum value given by the expression (3) in the PID controller. It's safe
501 007 also states that fuel discharge is shut off each time the vapor-air mixture is too diluted.
In accordance with a further feature of the present invention, the means for ensuring turbulent movement of the vapor-air mixture in said return line comprises upstream of the positive displacement pump of a spiral element inserted into said return line upstream of the positive displacement pump, or of granular material glued to the inner wall of the conduit, or of roughness of said wall by mechanical machining or chemical machining.
Finally, in accordance with the preferred embodiment of the present invention, the means for effecting turbulent movement of the vapor-air mixture in said conduit upstream of the positive displacement pump are provided in the portion of the return conduit located within the pump nozzle, the portion having a cross section substantially narrower than the rest. of the return line.
The invention described in detail below with reference to the accompanying drawings, which illustrate a preferred embodiment thereof, is given as a non-limiting example, while technical and structural modifications thereof can be made without departing from the scope of the present invention.
The drawings show:
Figure 1 is a diagrammatic cross-sectional view of a fuel filling plant using the steam recovery system according to the invention;
Figure 2 shows a block diagram of the instant-to-moment control circuits of the rotational speed of the positive displacement pump associated with the recycling system according to the invention.
In the drawings, 1 refers to the pumping column at a fuel filling plant and 2 to the underground tank belonging to the plant, the fuel 3, which is drawn in through the supply line 4 and the filter cartridge 5 by means of the feed pump 6 driven by the electric motor 7, is passed through the exhaust gas 8, the volumetric material flow meter 9 and thence to the discharge line 10 provided with a pump nozzle 11.
The meter 9, which measures the volumetric amount of material Qc of the fuel being discharged, is connected to the counter 12 and, via line 13, to the logic unit 14 to which is fed, via line 15, the measured temperature Tc of the fuel to be discharged, which is considered to be essentially the same
501 007 with that of the steam-air mixture contained in the judgment 16 belonging to the underground tank 2, and via conduit 17 the measured atmospheric pressure Po.
The pump nozzle 11 is provided with a second rigid conduit 18 for withdrawing the vapor-air mixture from the fuel filler tube of the vehicle tank to be filled (not shown in the figure), said conduit being connected to the return line 19 which transfers the mixture, through a filter cartridge 20, to the bottom of the the underground tank 2, from which it bubbles up in the judgment 16. This forced supply is effected by a positive displacement pump 21 and by connecting the manifold 22 with which the return lines of all the pumps of the plant communicate, to the fan of the plant 23, which in a known way connects the bottom of the underground tank 2 with the atmosphere.
Since said manifold 22 is always pressurized to prevent any steam-air mixture leakage into the atmosphere through the nozzle or fan, a non-return valve 24 is provided downstream of positive displacement pump 21 and a further control valve 25 is provided at the free end of fan 23. Again, to prevent the propagation of explosion, two flame valves 26 and 27 are provided at the end of channel 18 of the pump nozzle 11 which is connected to said return line 19 and downstream of the positive displacement pump 21.
In addition, in order to prevent and / or limit damage from any explosion in the steam condensing unit 28 which is of a conventional type and connected to a four-way two-position valve 29 and the conduit 30 to the judgment 16 in the underground tank 2, the return line 31 from this unit is provided with a suction pump 32 and is extended to the bottom of the underground tank 2 so that the recovered steam is forced, without having previously cooled, to reach the judgment 16 by bubbling, and in this way is cooled; of the fuel 3 in the underground tank 2.
The temperature Tm of the suction vapor-air mixture is measured upstream of the positive displacement pump 21, this measurement value is fed to the logic unit 14 via line 33, and the pressure drop A p of the return line mixture between the pump nozzle and the positive displacement pump is measured and fed to said logical unit 14 via wire 34.
In addition, since the accuracy of the Δρ measurement depends on the accuracy with which the effective values for the density of the withdrawn mixture are calculated, and on which the safety of the plant depends, the inner wall of the rigid channel 18 has been arranged in the pump nozzle 11.
501 007 for withdrawal of the vapor-air mixture artificially made, for example, by attaching granular material by gluing, so that, in addition to ensuring a turbulent movement of said mixture, since it is necessary for the validity of formula (2), a fixed artificial high pressure drop is created which makes all other pressure drops that occur along the return line 19 between the pump nozzle 11 and the pump 21 due to temporary reasons practically negligible. This artificial pressure drop is therefore what should be determined as the value Δ p.
Finally, said positive displacement pump 21 is driven by an electric motor 36 connected via lines 37 and 38 to logic unit 14 and is operated instantaneously for instant control of this latter at a rotational speed n expressed by expression (3). For this purpose, the logic unit 14 (see Figure 2) comprises a memory register 39 which, when fed at its input with measured values of temperatures Tc and Tm via lines 15 and 33, at its outputs 40 and 41 provides the vapor pressure values Pv (Tc) and Pv (Tm) at the two temperatures. These two outputs 40 and 41 are then fed, together with the measured atmospheric pressure value Po, derived from line 17 via line 42 and said values of Tc and Tm obtained from lines 15 and 33 through lines 43 and 44, to the input of a calculation unit 45 (operational unit) that calculates the expression <sub>+</sub> Po Pv (Tc) <sub>e</sub> Tm Po-Pv (Tm)
Po Tc Po
<img file="SE501007C2_D0004.tif" />
Output from the computing unit 45 is then fed to a comparator 47 which compares the value with I, and if it is less than 1 sets it equal to 1, otherwise the value is left unchanged. Output 48 from comparator 47 is fed to a multiplier unit 49 along with the measured value of the volumetric quantity Qc of fuel delivered via line 13, and with output Po from a further computing unit 51 which calculates the term ρθ &, and is fed at its inputs by lines 17 and 34 which provides the measured values for Po and for the pressure drop A p. A further memory register 52, which is fed by the value Tm derived from line 33 via line 53, provides at its outputs 54 and 55 the limiting density values g 1 and 2 which are fed to a third computing unit 56 to which output 57 of a second multiplier unit 58 is also fed. which essentially determines the value of the effective density? in accordance with the expression (2). In this regard, the multiplier unit 58 is output with output 59 from a memory 501 007 register 60 which, fed by the value Tm via said line 53, yields the value K (T), and output 61 from a further computing unit 62 which calculates the expression p<sup>A</sup>/ v ^ or, the same, the expression p<sup>A</sup>/ nb, by feeding with the value p derived from line 34 via line 63, and with feedback line 38 from electric motor 36 (see Figure 1) which provides the motor rotation speed n.
Output 64 from the third computing unit 56, which is essentially the value of the expression / 1 - · Π · ~ / is fed to a comparator 65 which does not change the value if it is between 0 and 1, sets the value equal to 1 if it is greater than 1, and sets it equal to 0 if the value is less than 0 and simultaneously emits a signal to shut off fuel output via line 66. Output 67 from comparator 65 is then also fed to said multiplier unit 49, whose output 68, which is essentially the value of the volumetric quantity Qm expression of (1), is divided by the known impact volume C of the positive displacement pump 21 in the divider 69, its output 70 provides the optimum rotation speed n of the positive displacement pump. Finally, output 70, along with said feedback line 38 from electric motor 36, is fed to a PID controller 71, the output of which is fed via a torque converter 72 to provide power to electric motor 36 via line 37.
501 007
Contents2
6 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6
23 members in 12 offices
Priority claims4
| Document | Office | Kind | Date |
|---|---|---|---|
| 1901689 | Italy | A | |
| 1901689 | Italy | A | |
| 1901689 | – | – | – |
| IT19890019016 | – | – | – |
Members23
| Document | Office | Kind | |
|---|---|---|---|
| IT8919016A0 | Italy | A0 | |
| IT8919016D0 | Italy | D0 | |
| SE8904389D0 | Sweden | D0 | |
| GB9000085D0 | United Kingdom | D0 | |
| DE4000165A1 | Germany | A1 | |
| SE8904389L | Sweden | L | |
| FR2641267A1 | France | A1 | |
| GB2226812A | United Kingdom | A | |
| NL9000011A | Netherlands (Kingdom of the) | A | |
| JPH02242798A | Japan | A | |
| BE1002735A4 | Belgium | A4 | |
| IT1228284B | Italy | B | |
| CH677920A5 | Switzerland | A5 | |
| US5038838A | United States of America | A | |
| FR2641267B1 | France | B1 | |
| ES2027089A6 | Spain | A6 | |
| GB2226812B | United Kingdom | B | |
| SE501007C2This record | Sweden | C2 | |
| DE4000165C2 | Germany | C2 | |
| RU2025464C1 | Russian Federation | C1 | |
| JP2789049B2 | Japan | B2 | |
| NL193588B | Netherlands (Kingdom of the) | B | |
| NL193588C | Netherlands (Kingdom of the) | C |
1 legal event, as the office reported them to INPADOC
Events
| Event | Code | |
|---|---|---|
| Patent has lapsedLapsedNUG | NUG |
Numbers
- Publication, DOCDB
- 501007
- Publication, EPODOC
- SE501007
- Application
- 8904389
- Application, DOCDB
- 8904389
- Application, EPODOC
- SE19890004389
Titles2
- Swedish
- System för säker återvinning av ånga, speciellt vid bränslepåfyllningsanläggningar
- English
- Systems for the safe recovery of steam, especially at refueling plants
Classification
- CPC, 3
- B67D7/0486
- B67D7/0476
- Y10T137/86324
- IPC, 2
- B67D7 04
- B67D7 76
