EP3647260A1 - Device for dispensing and recycling of fluids - Google Patents

Abstract

The invention relates to a device for delivering a first fluid and for returning a second fluid, comprising a main channel (13) for delivering the first fluid and a return channel (14) for returning the second fluid. According to the invention, a test channel (15) is provided which connects the main channel (13) to the return channel (14), the main channel (13) having a constriction (16) and the test channel (15) in the region of the constriction (16) in the Main channel (13) opens, the device further comprising a sensor (17) which is designed to determine a pressure in the test channel (15). The invention further relates to an outlet pipe, a fuel nozzle and a fuel dispenser, which has a device according to the invention. With the aid of the invention, an active return of the second fluid can be switched off in a simple and safe manner.

Description

The present invention relates to a device for delivering a first fluid and for returning a second fluid, comprising a main channel for delivering the first fluid and a return channel for returning the second fluid.

Such devices are used, for example, when refueling vehicles. A nozzle is inserted into a filler neck of the vehicle and the fuel is then released into a tank of the vehicle. In this process, fuel vapors already in the tank are displaced from it. So that the fuel vapors do not escape into the environment, it is known in the prior art to suck the vapors off via a return duct and, for example, to lead them to an underground fuel reservoir. Such a procedure is also called "active feedback" in the following.

An alternative solution to preventing fuel vapors from escaping is to equip the vehicle itself with a system to collect fuel vapors. Such systems are also called "onboard refueling vapor recovery" systems (systems for vehicle-side recovery of refueling vapors, hereinafter also referred to as ORVR systems). In a vehicle with such an ORVR system, the displaced fuel vapors are captured within the vehicle and, for example, fed to an activated carbon canister for separation.

If a vehicle equipped with an ORVR system is refueled by a dispenser with active feedback, the active feedback must be switched off, since all fuel vapors or at least a large part of the fuel vapors are already discharged through the ORVR system and essentially an additional active feedback Would suck in outside air and lead into the fuel reservoir. This should be avoided under all circumstances, since the air drawn in mixes with the gas vapors in the fuel reservoir and would cause an increase in pressure. For physical reasons, a much larger volume of the air-gas vapor mixture in relation to the introduced air volume would escape via the ventilation system of the fuel reservoir, which damages the environment as well as the economy.

In order to ensure that the active return is switched off in this way, it is known in the prior art to equip the nozzle with a sensor which detects whether the vehicle to be refueled has an ORVR system or not. For example, it is known to equip the outlet pipe of the nozzle valve with a bellows, which ensures an airtight seal around the filler neck. If a vehicle equipped with an ORVR system is now refueled with such a nozzle, there is a vacuum due to the airtight seal, which leads to the active feedback being switched off.

A disadvantage of these known systems is their unreliability and their complex construction. In particular, when the dispensing valve is placed at an angle, the bellows often does not provide an adequate airtight seal, so that the active return cannot be reliably switched off.

Against this background, it is the object of the present invention to provide a device for dispensing a first fluid and for returning a second fluid, which, with a simple structural design, enables safe deactivation of active return of the second fluid. This problem is solved with the features of the independent claims. Advantageous embodiments are specified in the subclaims. The device according to the invention has a test channel which connects the main channel to the return channel, the main channel having a constriction and the test channel opening into the main channel in the region of the constriction, the device further comprising a sensor which is designed to determine a pressure in the test channel is.

First, some terms used in the context of the invention are explained. In the context of the invention, the term fluid denotes a liquid or gaseous medium. The first fluid can in particular be a fuel, and the second fluid can be, for example, fuel vapors, air, or a mixture of fuel vapors and air.

The device according to the invention comprises a main channel for dispensing the first fluid and a return channel for returning the second fluid. An application and return can take place by connecting a corresponding application pump or a corresponding return pump to the respective channel. It is not necessary within the scope of the invention that the device according to the invention comprises these pumps themselves.

The term “sensor for determining a pressure” is to be understood broadly within the scope of the invention. It is possible, but not absolutely necessary, that the sensor be designed to indicate a numerical value of the pressure prevailing in the test channel. It can be provided that the pressure sensor is designed to detect an overshoot and / or undershoot of a pressure threshold.

When the first fluid is discharged, it flows through the main channel of the device according to the invention. In the area of the narrowing of the main channel, the flow laws of Bernoulli lead to a drop in the hydrostatic pressure, as a result of which a negative pressure is generated in the test channel when the test channel opens into the main channel. This effect is also known as the "Venturi effect". The second fluid is drawn into the test channel from the return channel by the negative pressure.

Within the scope of the invention, use is further made of the fact that when the second fluid enters the test channel into the test channel, a pressure drops behind an orifice of the test channel, the amount of which depends on the physical properties of the material (for example the density and / or the viscosity) of the second fluid. The effect that a certain pressure difference drops after passing through an opening or after passing through a local flow resistance, the amount of which depends on the physical properties of the fluid, is known in principle and is used, for example, in so-called "measuring orifices" or "throttles". The invention makes use of this effect by determining the pressure in the test channel with the aid of the sensor according to the invention. Conclusions can then be drawn from the measured pressure for example with regard to the mass density and / or the viscosity of the fluid flowing through the test channel. Since, in particular, fuel vapors have different physical properties compared to air, a distinction can be made in this way as to whether the second fluid drawn in is fuel vapors or air. Within the scope of the invention, the clear difference between the density of air (about 1.2 kg / m ³ at room temperature and under normal pressure) and the density of fuel vapors (about 3.4 kg / m ³ at room temperature and under normal pressure) or the difference between the viscosity of air (about 18 µPa * s at room temperature and normal pressure) and the viscosity of fuel vapors (about 7-12 µPa * s at room temperature and normal pressure) can be exploited. Depending on the measured pressure value, it can then be decided whether active recirculation of the second fluid is necessary or not. Compared to the prior art, there is the particular advantage that there is no need for a bellows with which an airtight closure to a tank is produced, so that the device according to the invention is structurally simpler and at the same time operates much more reliably.

In a preferred embodiment, the test channel has an aperture. In the context of the invention, an orifice denotes an object which restricts the flow cross section available in the channel. The orifice can also be referred to as local flow resistance. For example, the diaphragm can have an annular shape and a circular passage area in the middle of the diaphragm. When an orifice plate is used, an increased pressure difference can be generated, so that pressure determination in the test channel is simplified. For this purpose, the sensor is preferably arranged (as seen from the return duct) behind the screen. The Aperture can be arranged in particular in the mouth region of the test channel in the return channel.

The main channel is preferably designed to pass a substantially constant volume flow through the constriction. A constant volume flow through the restriction has the advantage that the suction power generated by the Venturi effect is also essentially constant. Since the suction power influences the pressure in the test channel, the assignment of a determined pressure value to a mass density of the sucked-in fluid is simplified with constant suction power. The volume flow through the restriction is preferably between 2 l / min and 20 l / min, more preferably between 5 l / min and 15 l / and even more preferably between 8 l / min and 12 l / min. Due to the Venturi effect, the volume flows mentioned lead to sufficient suction power so that a pressure value in the test channel can be reliably determined. For example, a spreading pump (upstream of the main channel flow direction) arranged upstream of the constriction can be designed to deliver a substantially constant volume flow through the main channel.

However, it may sometimes be desirable to vary the volume flow through the main channel in order to allow a more flexible application of the first fluid. In an advantageous embodiment, the main channel therefore has a bypass channel bridging the constriction. The term “bridging” here means that the bypass duct branches off from the main duct (in relation to the direction of flow) before the constriction and flows back into the main duct behind the constriction. This configuration is particularly advantageous if the first fluid has a variable volume flow through the main channel should be directed, but the volume flow through the constriction should remain constant. Through the bypass duct according to the invention, the volume flow can optionally be guided past the constriction, so that the volume flow through the constriction can be kept constant. For this purpose, the device according to the invention can furthermore have a bypass valve which is designed to control the flow through the bypass channel. The bypass valve is preferably biased into a closed position in which the bypass channel is closed. More preferably, the bypass valve can be brought from the closed position into an open position by a fluid pressure prevailing in the main channel, in which at least part of the first fluid flows through the bypass channel. In particular, it can be provided that the volume flow let through the bypass channel from the bypass valve is dependent on a total volume flow of the first fluid entering the main channel. The bypass valve according to the invention can be used in this way to ensure that the volume flow of the first fluid is kept essentially constant through the constriction. Preferred total volume flows which can be used in the context of the invention are in the range between 2 l / min and 100 l / min, preferably between 6 l / min and 80 l / min, more preferably between 8 l / min and 50 l / min .

In a preferred embodiment, the return channel of the second fluid can also be designed to pass an essentially constant volume flow. In particular, the return duct can be designed to pass a volume flow which is essentially identical to the volume flow of the first fluid. For this purpose, the device according to the invention can have a corresponding return pump, which is suitable for generating corresponding volume flows. It For example, a device for regulating the volume flow of the second fluid depending on the volume flow of the first fluid can be provided, which can be part of the device according to the invention or also part of a nozzle according to the invention described below or a nozzle according to the invention described below.

In a preferred embodiment, the device according to the invention further comprises a switching valve which is arranged in the return channel downstream of the test channel and which can be switched between an open position and a closed position, the switching valve opening the return channel for returning the second fluid in the open position and closing the return channel in the closed position. The sensor is preferably operatively connected to the switching valve, the switching valve being switched as a function of the pressure determined. In this way, the feedback can be switched off by closing the switching valve or switched on by opening the switching valve based on the pressure determined by the sensor.

The device according to the invention is preferably used when filling a fuel into a tank. For this purpose, a nozzle with an outlet pipe is usually used, whereby the nozzle can be connected to a fuel pump. A main channel and a return channel in the sense of the present invention can fundamentally extend from the outlet pipe via the dispensing valve to the dispenser. The features according to the invention can therefore in principle be arranged at any point in such a system consisting of an outlet pipe, fuel nozzle and fuel pump.

However, the features according to the invention enable a particularly compact design, so that it is possible to integrate the features according to the invention into an outlet pipe of a nozzle. The invention therefore also relates to an outlet pipe of a nozzle, which has a device according to the invention for dispensing a first fluid and for returning a second fluid. The outlet pipe according to the invention can be developed by further features which have been described in the context of the device according to the invention. If the features of the device according to the invention are realized in an outlet pipe, it is possible to replace the outlet pipe in a nozzle according to the prior art with an outlet pipe according to the invention and to retrofit the nozzle in this way with the features according to the invention. A corresponding dispensing valve, which comprises such an outlet pipe according to the invention, is also the subject of the invention. Finally, a dispenser is also the subject of the present invention, which has a dispensing valve according to the invention.

Further objects of the invention are also a dispensing valve which has the device according to the invention and a dispenser which has a device according to the invention.

Figur 1A:

eine schematische Ansicht einer erfindungsgemäßen Einrichtung zur Ausbringung eines ersten Fluids und zur Rückführung eines zweiten Fluids;

Figur 1B:

eine schematische Ansicht einer alternativen Ausführungsform der erfindungsgemäßen Einrichtung zur Ausbringung eines ersten Fluids und zur Rückführung eines zweiten Fluids;

Figur 2A:

eine Schnittansicht durch ein erfindungsgemäßes Auslaufrohr bei Ausbringung eines ersten Fluids mit geringem Volumenstrom und bei Rückführung eines zweiten Fluids;

Figur 2B:

ein Ausschnitt aus Figur 2A in vergrößerter Ansicht;

Figur 2C:

ein Ausschnitt aus Figur 2A in vergrößerter Ansicht;

Figur 3A:

die Schnittansicht der Figur 2A bei Ausbringung eines ersten Fluids mit hohem Volumenstrom;

Figur 3B:

ein Ausschnitt aus Figur 3A in vergrößerter Ansicht;

Figur 4A:

eine Schnittansicht durch ein erfindungsgemäßes Auslaufrohr bei Ausbringung eines ersten Fluids mit geringem Volumenstrom wobei keine Rückführung eines zweiten Fluids erfolgt;

Figur 4B:

ein Ausschnitt aus Figur 4A in vergrößerter Ansicht;

A preferred embodiment of the invention is explained below by way of example with reference to the accompanying drawings. Show it:

Figure 1A:

a schematic view of a device according to the invention for dispensing a first fluid and for returning a second fluid;

Figure 1B:

a schematic view of an alternative embodiment of the device according to the invention for dispensing a first fluid and for returning a second fluid;

Figure 2A:

a sectional view through an outlet pipe according to the invention when dispensing a first fluid with low volume flow and when returning a second fluid;

Figure 2B:

a cut out Figure 2A in an enlarged view;

Figure 2C:

a cut out Figure 2A in an enlarged view;

Figure 3A:

the sectional view of the Figure 2A when applying a first fluid with high volume flow;

Figure 3B:

a cut out Figure 3A in an enlarged view;

Figure 4A:

a sectional view through an outlet pipe according to the invention when dispensing a first fluid with a low volume flow, with no return of a second fluid;

Figure 4B:

a cut out Figure 4A in an enlarged view;

One in Figure 1A The embodiment according to the invention shown of a device for dispensing a first fluid and for returning a second fluid comprises a main channel 13, which is designed for the passage of the first fluid, for example a liquid fuel. The main channel 13 can be connected to a fuel reservoir, not shown be, from which fuel is pumped through the main channel 13 with the aid of a fuel pump. The main channel 13 comprises a constriction 16.

The device also has a return duct 14 through which a second fluid, for example a gas and in particular fuel vapors, air or a mixture of fuel vapors and air, can be passed. For this purpose, the return channel 14 can also be connected to a fuel reservoir (not shown), the second fluid being pumped out into the fuel reservoir via a return pump.

A test channel 15 extends between the main channel 13 and the return channel 14, which opens into the main channel 13 in the area of a first mouth 12 and into the return channel 14 in the area of a second mouth 19. The first mouth 12 is arranged in the area of the constriction 16. In the area of the second mouth 19 there is a flow resistance 18, which represents an orifice in the sense of the present invention. The flow resistance 18 limits the flow cross section available for the transition into the test channel 14. The test channel 14 is also connected to a pressure sensor 17, which is designed to determine a fluid pressure in the test channel 15.

If a fuel is pumped through the main duct 13, the venturi effect causes a decrease in the hydrostatic pressure in the area of the constriction 16. The vacuum located in the return duct 14 draws gas into the test duct 15. This creates a pressure difference at the flow resistance when entering the test channel, which is caused by the physical properties of the gas being sucked in depends. In this way, it can be determined from the pressure value determined whether the gas drawn in is air or fuel vapors.

Figure 1B shows an alternative embodiment of the device according to the invention for dispensing a first fluid and for returning a second fluid. Essential elements of this embodiment are identical to those of the Figure 1A and provided with the same reference numerals.

In contrast to the embodiment of the Figure 1A a further opening 126 is arranged in the region of the constriction 16 and is connected to the ambient air via a reference opening 46. When a fuel is pumped through the main duct 13, outside air is therefore sucked in via the reference opening 46.

The pressure sensor 17 in the embodiment of FIG Figure 1B also has a test chamber 40 which is in fluid communication with the test channel 15 via a test line 41. The sensor 17 also includes a reference chamber 42, which is connected to the reference opening 46 via a reference line 45. Finally, the sensor comprises a pressure-sensitive membrane 43, which separates the test chamber 40 from the reference chamber 42.

The membrane 43 is connected to a plunger 44 via a release mechanism, not shown. The membrane 43 is designed to actuate the trigger mechanism as a function of a pressure difference between the test chamber 40 and the reference chamber 42 and thus move the tappet 44 from an open position in which the return channel 14 is open (not shown) to the position shown in FIG Figure 1B bring closed position shown, in which the Return channel is closed. For this purpose, the plunger 44 is moved by the trigger mechanism.

As long as fuel vapors are passed through the return line 14, the pressure within the test chamber 40 remains at a value at which the tappet 44 remains in the open position. If larger quantities of air are passed through the return duct 14, the pressure in the test chamber 40 increases. As soon as a certain pressure threshold value is exceeded, the membrane 43 moves and, as a result, triggers the trigger mechanism by which the plunger 44 enters the valve Figure 2 shown closed position is moved.

The Figure 2A shows a cross-sectional view through an outlet pipe 30 according to the invention for the discharge of a fuel and for the return of a gas, the fuel being discharged with a low volume flow. The already in connection with the Figures 1A and 1B described inventive elements in the Figure 2A same reference numerals and are not explained again below. In the Figure 2A are drawn a circular section A and a rectangular section B, which in the Figures 2B or 2C are shown enlarged.

The outlet pipe 30 has a front end 31 and a rear end 32. The front end 31 can be inserted into a filler neck of a vehicle tank (not shown), for example, for dispensing fuel. The rear end 32 can be inserted into a nozzle valve, not shown. Instead of the plunger 44, the outlet pipe according to the invention comprises a switching valve 22 which is connected to a release mechanism 23. The pressure sensor 17 in the embodiment of FIG Figure 2A as well as the embodiment of the Figure 1B a pressure-sensitive membrane 43, which is in operative connection with the trigger mechanism 23. The outlet pipe further comprises a bypass channel 21 and a bypass valve 20. The bypass valve 20 is biased by a reset device 25 into a closed position, in which it rests on a valve seat 24.

At the in Figure 2A shown state, a fuel with a low volume flow of about 10 l / min is passed through the main channel 13. The low volume flow in the main channel 13 is not able to open the bypass valve 20 against a closing force of the resetting device 25, so that the bypass valve 20 remains in its closed position. This is particularly true in Figure 2C can be seen in which it can be seen that the bypass valve 20 rests on an associated valve seat 24 and the bypass channel 21 is closed. The volume flow flowing through the main channel 13 is therefore passed completely through the constriction 16. When the volume flow through the main channel 13 increases (for example up to 50 l / min), the bypass valve 20 is moved from the closed position into an open position by the fluid pressure, so that part of the volume flow through the bypass channel 21 can flow past the constriction 16 . This is in the Figures 3A and 3B illustrates which, moreover, with the Figures 2A and 2C to match. The higher the volume flow through the main channel 13, the further the bypass valve 20 opens. The volume flow through the constriction 16 can in this way be kept constant at about 10 l / min, so that the test channel 15 is evacuated with a constant suction power.

Furthermore, in the Figure 2A State shown fuel vapors discharged via the return channel 14. The exhaustion The fuel vapors ideally take place with the same volume flow with which the fuel is conducted through the main channel 13, so that there is a constant ratio of fuel to fuel vapors. As already referring to Figure 1A described, a negative pressure is generated when the fuel is passed through the main duct 13 in the test duct 15, which leads to a suction of fuel vapors located in the return duct 14. The volume flow of fuel vapors sucked in through the test channel 15 is added to the volume flow of the fuel in the main channel 13 and is negligibly small compared to this.

The space above the membrane 43 corresponds to that in FIG Figure 1B shown test chamber 40, but is not provided with a reference number for reasons of space. The test chamber is connected to the test channel 15, this connection not being recognizable in the sectional view shown. The pressure prevailing in the test channel 15 has a direct effect on the membrane 43. The space below the membrane corresponds to that in Figure 1B shown reference chamber 42. The reference chamber is - as in the Figure 1B shown - connected via the reference line 45 to the reference opening 46, this in the Figures 2A-4B is not recognizable. The further opening 126 is also in the Figures 2A-4B not visible.

The membrane 43 is operatively connected to the switching valve 22 via the release mechanism 23, which in the embodiment shown is prestressed by a spring, for example. In alternative embodiments, the trigger mechanism can also be under pressure or acted upon by a magnetic force. In the Figure 2A shown operating conditions (when drawing in fuel vapors) there is a negative pressure of about -0.060 bar in the test chamber relative to the reference chamber a. This negative pressure is below a pressure threshold (which can be, for example, -0.050 bar), at which the membrane 43 moves and triggers the trigger mechanism 23. The switching valve 22 therefore remains in the open state shown, in which the fuel gases are discharged via the return duct 14.

If the vehicle to be refueled is a vehicle with an ORVR system, essentially air is discharged via the return duct 15. Due to the different physical properties of the exhaust air compared to fuel vapors, there is a pressure increase in the test duct 15 and thus also in the test chamber, so that the negative pressure is only about -0.045 bar relative to the reference chamber. When air is removed, the pressure threshold value of - 0.050 bar is therefore exceeded, at which the membrane 43 moves and triggers the trigger mechanism 23. In this case, the triggering mechanism causes the switching valve 22 to switch to the closed position. This state is shown in FIGS. 4A and 4B, which, moreover, with the Figures 2A and 2C to match. In the in Figure 4A shown state, the gas recirculation is thus prevented by the switching valve 22.

Claims (15)

Device for delivering a first fluid and for returning a second fluid, comprising a main channel (13) for delivering the first fluid and a return channel (14) for returning the second fluid, characterized by a test channel (15) which defines the main channel (13) connects to the return duct (14), the main duct (13) having a constriction (16) and the test duct (15) opening into the main duct (13) in the region of the constriction (16), the device further comprising a sensor (17) which is designed to determine a pressure in the test channel (15). Device according to Claim 1, in which the test channel (15) has an aperture (18). Device according to Claim 2, in which the sensor (17) is designed to determine the pressure behind the orifice (18). Device according to one of claims 1 to 3, wherein the main channel (13) is designed to pass a substantially constant volume flow through the constriction (16), the volume flow through the constriction preferably between 2 l / min and 20 l / min , more preferably between 5 l / min and 15 l /, still more preferably between 8 l / min and 12 l / min. Device according to Claim 4, in which the main channel (13) has a bypass channel (21) bridging the constriction (16), a bypass valve for controlling the flow through the bypass channel (21) preferably being provided. Device according to Claim 5, in which the bypass valve (20) is biased into a closed position in which the bypass channel (21) is closed, the bypass valve (20) being movable from the closed position into an open position by a fluid pressure prevailing in the main channel (13) in which at least part of the first fluid flows through the bypass channel (21). Device according to claim 5 or 6, in which the volume flow let through bypass valve (20) through the bypass channel (21) depends on a total volume flow of the first fluid entering the main channel. Device according to one of Claims 1 to 7, in which the return duct (14) is designed to pass a volume flow which is essentially identical to the volume flow of the first fluid and preferably between 5 l / min and 100 l / min, more preferably between 8 l / min and 80 l / min and particularly preferably between 10 l / min and 50 l / min. Device according to one of claims 1 to 8, which further has a switching valve (22) which is arranged in the return channel (14) downstream of the test channel (15) and which can be switched between an open position in which the switching valve (22) returns the return channel (14) Returns the second fluid, and a closed position in which the switching valve (22) closes the return channel. Device according to Claim 9, in which the sensor (17) is operatively connected to the switching valve (21), the switching valve (22) being switched as a function of the pressure determined. Outlet pipe of a nozzle, characterized in that it has a device according to one of claims 1 to 10. Dispensing valve comprising an outlet pipe according to claim 11. Dispensing valve, characterized in that it has a device according to one of claims 1 to 10. Petrol pump, characterized in that it has a device according to one of claims 1 to 10. A fuel dispenser comprising a fuel dispenser according to claim 12.

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