Vapour recovery system

Abstract: A vapour exhaust system has a volumeter 5 and an air pump 7 mechanically coupled therewith, to let the volume of the amount of fluid pumped over correspond with the amount of air pumped out of a fuel tank. A translating and rotating move­ ment provides the signal to maintain the correspondence, in which cases the crankshaft 10 of the volumeter 5, is coupled to the air pump possibly being formed as a gear-wheel pump. At wish coupling can take place via a gear transmission.

Description: The invention relates to a system for pumping over a fluid and an equal corresponding quantity of vapour in opposite direction, said system having a tank, a pump and a mechanical volumeter, which are mutually coupled by means of conduits for transferring fluid from said tank to another tank, and having a mechanical air pump being connected to both tanks via air conduits, said volumeter, which is a double-acting volumeter, has a piston rod, whose translating motion contains a measure for the momentaneous fluid yield of the volumeter, and a piston to which a further rod and a further piston of the air pump are connected, said further piston dividing the cylinder of the air pump into parts, on each of which parts two valves are provided for realizing a double-acting air pump. Such a system is known from US-A-4 223 706 and is e.g. used in pumping stations on e.g. factory grounds, where more or less toxic, or possibly volatile fluids must be pumped over from the one storage tank to the other, without the vapour formed or being formed in the receiving tank finding its way into the enviroment via the inlet. Not only does this have a pollution effect, but also, since the vapour originates from said fluid, the loss of vapour constitutes a taste of said fluid. It is obvious that said environmental pollution as well as said waste are inadmissible. In order to keep ahead of these problems the known system has employed two generally known cylinder-piston pumps, whereby the one pump is located inside the fluid channel, whilst the other pump is accommodated in an air conduit. When the fluid pump is set going also the air pump is set going, whereby during operation of the system a volume of fluid which has been pumped during a certain period of time corresponds with the volume of air transferred. The object of the invention is to provide a system for pumping over fluids which can be manufactured in a simple manner and at a relatively low cost price. In order to accomplish that objective the invention is characterized in that said volumeter has at least one further piston, coupled via the piston rod, with corresponding cylinders, and that said volumeter furthermore has a crankshaft which is rotatable within said piston rod, said crankshaft being rotated by a translating motion of said piston rod, that one end of said crankshaft has a valve whereby, by rotation of the crankshaft, two passages to the corresponding cylinders are alternately released in the direction of an outgoing conduit of the volumeter. One advantage of the system according to the invention that can be mentioned is that the valves to be used may be automatically operating valves, without a complicated regulating/control system being required for operating said valves. The object of the invention can also be accomplished by a further system for pumping over a system for pumping over a fluid and an equal corresponding quantity of vapour in opposite direction, said system having a tank, a pump and a mechanical volumeter, which are mutually coupled by means of conduits for transferring fluid from said tank to another tank, and having a mechanical air pump being connected to both tanks via air conduits, said volumeter, which is a double-acting volumeter, has a piston rod and a piston, which in accordance with the invention is characterized in that said volumeter has at least one further piston, coupled via the piston rod, with corresponding cylinders, and that said volumeter furthermore has a crankshaft which is rotatable within said piston rod, said crankshaft being rotated by a translating motion of said piston rod, that one end of said crankshaft has a valve whereby, by rotation of the crankshaft, two passages to the corresponding cylinders are alternately released in the direction of an outgoing conduit of the volumeter, that the volumeter, which is thus a double-acting volumeter, has said crankshaft at its other end lengthened to form a common crankshaft, whose rotating motion contains a measure for the momentaneously fluid yield of the volumeter to which common crankshaft the drive shaft of an air pump formed as a gear pump is coupled. One embodiment worked out in more detail is according to the invention characterized in that the system contains a gear transmission provided between the crankshaft of the volumeter and the drive shaft of the gear pump, said gear transmission having a transmission ratio such that the fluid yield of the volumeter per time unit corresponds with the air yield of the gear pump. The advantage of this embodiment according to the invention is that by selecting the transmission ratio of the gear transmission gear pumps having different air yields can be utilized, at least as long as the yield per time unit of the gear pump-transmission combination is substantially the same as the fluid yield of the volumeter. The invention will be explained in more detail hereinafter with reference to the following Figures, in which corresponding elements have been given the same reference numbers. In the Figures: Figure 1 is a diagrammatic illustration of the system according to the invention; Figure 2 is a detailed illustration of a volumeter, realised in a mechanical manner, with an air pump for use in the system according to Figure 1; Figure 3 is a further detailed illustration of a volumeter, realised in a mechanical manner, which is connected, via a gear transmission, with an air pump for being used in the system according to Figure 1; and Figure 4 is an illustration of a cross-section along the line A - A of the air pump illustrated in Figure 3. Figure 1 shows a system 1 for pumping over a fluid from a tank 2, e.g. in the shape of a storage tank, to a tank (not shown) in e.g. a passenger car 3. The system 1 has a pump 4, which is connected in series to a volumeter 5, mutually connected via conduits 6, through which the fluid is pumped from the tank 2 to the other tank in the passenger car 3. An air pump 7 is coupled to the volumeter 5, said air pump being connected to air conduits 8 via a boundary plane 9. Between the volumeter 5 and the air pump 7 information is transmitted by means of a signal which is a measure for the momentaneous fluid yield of the volumeter, in such a manner that as a result of this the momentaneous yields of the volumeter 5 and the air pump 7 correspond. By this it is achieved that at any point of time during the cycle during which fluid is pumped, the quantity of air to be pumped in the opposite direction accurately corresponds with the volume of the fluid displaced, as a result of which there will not be an over-pressure or an under-pressure in the tank 2 and in the car 3 at any moment during said cycle. The signal which is transmitted via the boundary plane 9 is a measure for the momentaneous yield of the volumeter 5. If desired said signal may be an electric, a pneumatic or a mechanical signal. When the volumeter is an electric volumeter, said meter will generally also deliver an electric signal for a counting mechanism (not shown), said electric signal being a measure for the momentaneous yield of the volumeter 5. In that case said electric signal may be used for being transmitted, via the boundary plane 9, to the air pump 7, in order that the electric (in that case) air pump 7 pumps a volume of air which corresponds with the volume of the quantity of fluid displaced by the volumeter 5. When a volumeter of another type is used, said volumeter e.g. delivers a pneumatic signal, the momentaneous pressure of said pneumatic signal being a measure for the momentaneous fluid yield. In that case said pneumatic signal may be used for controlling the momentaneous air yield of the air pump 7, possibly after said pneumatic signal has been converted into e.g. an electric or a mechanical signal. When on the contrary the volumeter 5 is a mechanical volumeter, it is possible to use e.g. the rotational speed of a possible crankshaft, or the translation motion made by a possible piston as a signal to be transmitted to the air pump 7 via the boundary plane 9. Figures 2 and 3 show an embodiment of in particular a volumeter 5 with an air pump 7, wherein the influencing via the boundary plane 9 takes place mechanically. More in particular a translating motion is transmitted via the boundary plane 9 in the embodiment according to Figure 2. In this specific embodiment, in which the volumeter 5 and the air pump are even of the double-acting type, the volumeter 5 has a crankshaft 10, cylinders 11 and 11′ and pistons 12 and 12′ which are movable in the respective cylinders, said pistons being mutually coupled by means of a piston rod 13. Said piston rod 13 is journalled in the crankshaft 10. In the embodiment according to Figure 2 the crankshaft 10 is journalled at one side in some kind of a pivot bearing 14 and at the other side it is provided with a valve 15 mounted on the crankschaft 10. The valve 15 is designed such that it successively opens and closes, dependent on the position of the crankshaft 10, when the crankshaft passages 16 and 16′ are rotated towards the respective cylinders 11 and 11′, as a result of which fluid which enters via the conduit 6, so forced by the pump 4, is transferred to the conduit 6 with the pump, which is thus a double-acting pump. The momentaneous position of the pistons 12 and 12′, or the derivative thereof, is a measure for the momentaneous yield of the volumeter 5. The piston rod 13 is lengthened into a common rod 17, which projects through the boundary plane 9, and through which the mechanical (in this case) signal, which is a measure for the momentaneous yield of the volumeter 5, is transmitted to the double-acting (in this case) air pump 7. A piston 18 is secured to the common rod 17, which piston is movable in the cylinder 19 of the air pump 7. The piston 18 divides the cylinder 19 into two parts, viz. 19′ and 19″. To each of said parts 19′ and 19″ of the cylinder 19 there are secured pairs of valves 20, 21. Said valves 20 are connected to the conduit 8 for guiding the vapour to the tank 2, whilst the valves 21 at the other side of the air pump 7 are likewise connected to the conduit 8, via which vapour is pumped from the tank in the car 3. In this embodiment both the air pump 7 and the volumeter 5 are double-acting. It is obvious that the principle as presented hereinabove can also be used in single-acting pumps and that, as already explained before, it can also be used when the volumeter 5 and the air pump 7 have e.g. an electric arrangement. In the embodiment according to Figure 3 the crankshaft 10 has been lengthened and it projects through the boundary face 9. Said crankshaft 10 is coupled, via a gear transmission 22, to a drive shaft 23 of the rotatable air pump 7, which is preferably a gear pump. Air conduits 8 are connected to the pump 7. Figure 4 shows a cross-section along the line A - A of the gear pump 7 illustrated in Figure 3. The drive shaft 23 drives a rotor 25 provided with openings 24 at its circumference. In said openings 24 a quantity of air or vapour is caught on rotation of the rotor 25. The transmission ratio of the gear transmission is to be selected such that the eventual quantity of air displaced by the pump 7 is at least equal to the quantity of fuel displaced by the volumeter 5, so that any losses or leakages do not result in the exhausted vapour finding its way into the environment.

Claims: A system (1) for pumping over a fluid and an equal corresponding quantity of vapour in opposite direction, said system (1) having a tank (2), a pump (4) and a mechanical volumeter (5), which are mutually coupled by means of conduits (6) for transferring fluid from said tank (2) to another tank, and having a mechanical air pump (7) being connected to both tanks via air conduits (8), said volumeter, which is a double-acting volumeter, has a piston rod (13), whose translating motion contains a measure for the momentaneous fluid yield of the volumeter (5), and a piston (12) to which a further rod (17) and a further piston (18) of the air pump are connected, said further piston (18) dividing the cylinder (19) of the air pump (7) into parts (19', 19''), on each of which parts two valves (20, 21; 20', 21') are provided for realising a double-acting air pump, characterised in that said volumeter (5) has at least one further piston (12'), coupled via the piston rod (13), with corresponding cylinders (11, 11'), and that said volumeter (5) furthermore has a crankshaft (10) which is rotatable within said piston rod (13), said crankshaft (10) being rotated by a translating motion of said piston rod (13), that one end of said crankshaft (10) has a valve (15) whereby, by rotation of the crankshaft (10), two passages (16, 16') to the corresponding cylinders (11, 11') are alternately released in the direction of an outgoing conduit (6) of the volumeter (5). A system (1) for pumping over a fluid and an equal corresponding quantity of vapour in opposite direction, said system (11) having a tank (2), a pump (4) and a mechanical volumeter (5), which are mutually coupled by means of conduits (6) for transferring fluid from said tank (2) to another tank, and having a mechanical air pump (7) being connected to both tanks via air conduits (8), said volumeter, which is a double-acting volumeter, has a piston rod (13) and a piston (12), characterised in that said volumeter (5) has at least one further piston (12'), coupled via the piston rod (13), with corresponding cylinders (11, 11'), and that said volumeter furthermore has a crankshaft (10) which is rotatable within said piston rod (13), said crankshaft being rotated by a translating motion of said piston rod (13), that one end of said crankshaft (10)) has a valve whereby, by rotation of the crankshaft (10), two passages (16, 16') to the corresponding cylinders (11, 11') are alternately released in the direction of an outgoing conduit (6) of the volumeter (5), that the volumeter (5), which is thus a double-acting volumeter, has said crankshaft (10) at its other end lengthened to form a common crankshaft (10), whose rotating motion contains a measure for the momentaneously fluid yield of the volumeter to which common crankshaft (10) the drive shaft (23) of an air pump (7) formed as a gear pump is coupled. A system according to claim 2, characterised in that the system (1) contains a gear transmission (22) provided between the crankshaft (10) of the volumeter (5) and the drive shaft (23) of the gear pump (7), said gear transmission (22) having a transmission ratio such that the fluid yield of the volumeter (5) per time unit corresponds with the air yield of the gear pump (7).

Inventors: WILLEMSEN HENRICUS JOHANNES AR, WILLEMSEN, HENRICUS JOHANNES ARNOLDUS
Applicants: KOPPENS AUTOMATIC FABRIEKEN BV, KOPPENS AUTOMATIC FABRIEKEN B.V.
Application year: 1990
Main classification: B67D5
IPC codes: B67D7