MXPA01009356A - Safety valve, in particular for a refuelling vent line - Google Patents

Abstract

The invention relates to a safety valve, in particular for a refuelling vent line between the tank filler neck and the activated charcoal container in a motor vehicle. The safety valve (1) which is located in the refuelling vent line is configured as a float valve. When fuel penetrates the refuelling vent line and as a result the safety valve (1), the outlet (4) of the safety valve (1) is closed using the float (7). The safety valve (1) is provided with an anti-pollution pipe-end (5) which opens into the environment and which is closed under normal pressure by a closure (6) that is actuated by a membrane (8). If the pressure in the safety valve (1) increases, the membrane (8) causes or helps the closure (6) on the anti-pollution end-pipe (5) to open.

Description

SAFETY VALVE FOR A FUEL INLET VENTILATION DUCT DESCRIPTION OF THE INVENTION It is known to provide suction devices in the fuel intake ducts of the service stations, in order to return the gases produced during the delivery of the fuel and thus not let them out into the environment. However, this is often not enough to completely avoid damage to the environment. In addition there are also service stations that do not have comparable devices. Therefore, in several countries there is a provision for cars with Otto petrol engines to evacuate to a container of activated carbon not only the hydrocarbons that evaporate from the tank during parking and driving, but also the gases with hydrocarbon content that are expelled from the gas tank during the fuel intake. Therefore, modern vehicles incorporate appropriate devices with tank ventilation systems. Thus, the fuel tank is usually communicated with the activated carbon container through an operating ventilation duct, so that the gases escaping from the tank during driving and parking when refueling are deposited in the container. active carbon.

In addition, a second ventilation device is provided for the fuel intake whose cross-sectional dimensions are much larger, which communicates the intake pipe of the tank with the activated carbon container. In the case of fuel loading, when the spigot tap is inserted in the intake pipe, a gate is opened that allows gases that are produced during the intake and also those that are expelled from the tank through the fuel supply to flow into the conduit. Ventilation of the intake and, consequently, to the activated carbon container. So that during the dispatch process gases can not escape into the atmosphere between the intake pipe and the tap of the spout, in the valuated concepts a joint is provided between the intake pipe and the spout tap. However, in the known design and arrangement of the ventilation duct for the fuel intake, the risk can not be excluded that, in the case of a malfunction of the faucet of the jet, for example if it is not disconnected when the fuel is full. tank or also in the case of an abusive overfill of the tank, liquid fuel arrives in the activated carbon container through the ventilation duct for the fuel intake. This introduction of liquid fuel to the activated carbon container results in an alteration of the formation of the mixture and possibly also damage to the catalyst. For this reason, a safety valve is located in the ventilation duct for the fuel intake, which must securely prevent an entry of liquid fuel into the coal container. DISCLOSURE OF THE INVENTION From the above-mentioned prior art, the invention has for its object to create a safety valve, in particular for a ventilation duct for the intake of fuel between the intake pipe of the tank and the active carbon container in the tank. a motor vehicle, which safely prevents the entry of liquid fuel into the active carbon container. The solution of the imposed problem is carried out according to the invention by the fact that the safety valve that is incorporated in the ventilation duct for the fuel intake is designed as a float valve, and because when fuel enters the ventilation duct for the intake of fuel, and with it in the safety valve, the safety valve outlet is closed through the float, and in the safety valve an environment tube is provided that empties into the environment, which the normal pressure is closed by a membrane-operated seal, being that the membrane causes and assists an opening of the closure of the tube that opens into the surroundings in the event of an increase in the pressure in the safety valve. Consequently, when fuel enters the safety valve, the valve outlet is initially closed to the activated carbon container and then the closure that opens into the environment as a result of the accumulation of pressure in the valve and the penetrating fuel opens. You can escape to the environment. The float swings about an axis of rotation disposed laterally below the outlet and is provided with a linkage that drives a disk valve at the outlet of the valve. As soon as the float swings around its axis the valve disc moves towards its valve seat and the outlet becomes clogged. The disc valve itself can be guided in the outlet tube by means of a guide rail. In a very simple manner, the linkage can be formed by a bolt joined to the disk valve and a sliding slide attached to the float housing the bolt. The float is held in its extreme positions by a bistable spring. This prevents the float opening the valve too prematurely. The opening of the disk valve takes place only when the lift of the float drops below an adjustable value due to the discharge of the fuel.

The closing for the tube of the environment is formed by a disk valve that is under spring pressure, which is operated through a linkage by the membrane arranged in the body of the valve. The membrane works according to the pressure in the valve. By closing the outlet to the activated carbon container, pressure builds up in the valve. This pressure acts on the membrane that opens the valve of the surroundings through a lever linkage against the force of the closing spring. To ensure that, in the case of fuel intake, the pressure losses due to the flow of the pipe between the safety valve and the activated carbon container and the strangulation losses in the activated carbon container do not cause premature opening of the closure of the Environment tube requires a comparatively fast equilibrium between the exit of the safety valve and the upper surface of the membrane. For this reason the upper surface of the membrane is covered by a cover, and the internal space between the membrane and the cover is communicated through a channel with the tube of the valve towards the container of activated carbon. As soon as the tube of the outlet to the activated carbon container is not closed, the pressure existing in the valve body is transmitted through the channel to the upper surface of the membrane, so that between the upper surface and the inner surface of the membrane there is the same pressure. In this case the valve of the environment only opens in the case of a pressure in the valve body with which the force of pressure on the body of the valve of the environment exceeds the force of the closing spring of the valve of the environment. In this the mouth of the channel to the outlet can be included in the sealing seat of the disc valve, so that by means of the disc valve both the outlet and the channel are closed. To ensure that after flooding the valve with fuel and opening the closure of the surrounding pipe the fuel that is in the pipe of the intake pipe of the tank to the valve and in the valve is completely discharged through the pipe of the environment is provided in the membrane a buffer function. For this purpose, an intermediate wall with a check valve is included in the internal space of the membrane, for example a mushroom-like membrane, and the adjacent space formed by the lid and the intermediate wall is connected through an adjacent channel with the outlet, wherein the sealing surface of the mushroom-like membrane is provided with at least one throttling groove. In place of the throttling groove it is also possible to provide a defined roughness or porosity in the membrane. In the case of applying pressure to the membrane, the air volume of the internal space is expelled towards the tube of the activated carbon container through the surface of the mushroom-like membrane that rises. After opening the valve of the surrounding pipe there is a reduction in the pressure in the safety valve, and the fuel flows into the environment. In order to achieve a total emptying of the safety valve and the conduit from the intake pipe, the air entrance to the space above the membrane is delayed by the throttling groove or a roughness defined in the membrane contact surface. of retention or opposite surface, so that the valve of the environment only closes again with a temporary delay. Finally, it is convenient under certain conditions to configure the valve body in the region of the closure as a depression, in order to prevent the gas in the safety valve from flowing out when the environmental pipe is opened, and eventually fuel remains inside it. By means of the depression it is achieved that the gas can only escape when the level of the fuel falls below the level of one edge of the body located above.

BRIEF DESCRIPTION OF THE DRAWING In the following embodiment, the invention is explained in more detail on the basis of the attached drawing. They show: Figure 1 a longitudinal section through the safety valve, Figure 2 a section according to the line AA of Figure 1 through the safety valve, and Figure 3 a section according to the line BB of the figure 1. Embodiment of the invention The safety valve 1 is constituted by a body 2 with an inlet 3 and the outlet 4 as well as the tube 5 of the environment. The gases coming from the intake pipe of the tank are led by the ventilation duct for the fuel intake to the inlet 3 of the valve 1, and through the outlet 4 they reach the portion of the duct of the activated carbon container. The outlet 4 of the safety valve 1 can be closed, likewise the tube 5 of the environment, which under normal conditions is always closed by closing 6. The outlet 4 is always open under normal conditions. It can be closed by the float 7 if fuel enters the safety valve 1. But the fuel that penetrates not only causes a closing of the outlet 4 by means of the float 7, but also an increase in the pressure in the safety valve 1. The increase in pressure results in an upward movement of the membrane 8, so that the plate 9 of the membrane passes with the membrane 8 from its lower position to the upper position outlined. The membrane 8 is connected to a linkage 10 through which the opening of the closure 6 is achieved. If fuel enters the safety valve 1 through the inlet 3, the float 7 swings around a laterally arranged pivot axis 11. below exit 4 (see also figures 2 and 3). A slide 12 is provided in the float, which with its slit 13 in the slide houses a bolt 15 placed in the valve 14 that closes the outlet 4. The disk valve 14 is guided in the discharge tube 17 over a guide rail 16 of 3 wings. A bistable spring 18 is provided on the float 7, which with one leg 19 is fixed to the float 7 while the other leg 20 attacks the cross piece 21. The closure 6 is also configured as a disk valve 25 and is pressed against the seat of the float. the valve by means of the spring 26. The plate 9 of the membrane is provided with the rod 27 which hinges its end articulatedly to the elbow lever 29 which rotates about the axis 28. The elbow lever 29 operates the pusher 30 of the valve 25 of the disk. The pusher 30 is guided on the cross member 31. The pusher 30 is provided with a bend 32 which is guided below the wall 33. The wall 33 serves as a gas blocking wall, so that to the tube 5 of the environment the gases they can only arrive when the level of the liquid descends below the lower edge of the blocking wall 33. This is further assisted by the configuration in the form of depression of the entire body 2 by configuring the body with the lowest point as a depression in the region of the closure 6. The cover 35 covers the membrane 8. The internal space 36 that is produced between the cover 35 and the membrane 8 communicates through the channel 37 with the outlet 4. In this the mouth 38 of the channel to the outlet 4 is included in the seat 39 sealant of the seat of the disc valve, so that the valve 14 closes both the outlet 4 and the channel 37. This prevents premature closing of the closure 6 before the exit is opened. A dead step can be included in the linkage, so it works with a delay. It is then possible to dispense with channel 37 and channel 43 annexed is sufficient. The proper rigidity of the membrane 8 is sufficient as back pressure to push the linkage back and close the valve of the environment.

Another improvement of the damping effect when closing the closure 6 of the tube 5 of the environment it is achieved by incorporating in the internal space 36 between the membrane 8 and the lid 35 an intermediate wall 40 provided with a mushroom-like membrane 41. Then, between the lid 35 and the intermediate wall 40 with mushroom-like membrane 41, the space 42 is produced. This adjacent space 42 communicates through the channel 43 annexed with the discharge tube 17. In the sealing surface of the mushroom-like membrane 41 abutting the intermediate wall 40 there is provided at least one throttling groove through which the gas can flow retarded from the tube 17 to the internal space 36. In this way the membrane 41 type fungus causes a rapid exit of the gases from the space 36 through the openings 44 in the intermediate wall 40 towards the adjacent space 42 and from there through the channel 43 to the tube 17. While in the other direction the influence is considerably retarded of gases through channel 43, the adjacent space 42 and the throttling grooves are not drawn in greater detail on the sealing surface of the mushroom-like membrane 41. It is still noted that the membrane 8 only acts when the valve 6 is closed. In the case of the open outlet 5, the safety valve acts as a direct overflow valve.

Claims (12)

1. CLAIMS 1. Safety valve, in particular for a ventilation duct for the intake of fuel between the intake pipe of the tank and the container of activated carbon in a motor vehicle, characterized by the fact that the safety valve that is incorporated in the ventilation duct for the fuel intake is designed as a float valve, and because when fuel enters the ventilation duct for the fuel intake and thus in the safety valve, the safety valve outlet is closed Through the float, being in the safety valve is provided an environment tube that opens into the environment which at normal pressure is closed by a closure actuated by a membrane, being that the membrane causes and assists an opening of the closure of the tube that flows into the environment in the event of an increase in the pressure in the safety valve.
2. 2. Safety valve according to claim 1, characterized in that the float swings about an axis of rotation arranged laterally below the outlet and is provided with a linkage that drives a valve valve at the outlet of the valve.
3. 3. Safety valve according to claim 1 or 2, characterized in that the disk valve is guided through a guide rail in the outlet pipe of the valve.
4. Valve according to one of claims 1 to 3, characterized in that the linkage is constituted by a bolt connected to the disk valve and a sliding slide attached to the float housing the bolt.
5. Valve according to one of claims 1 to 4, characterized in that the linkage has a dead passage region.
6. Valve according to one of claims 1 to 5, characterized in that the float is held in its extreme positions by a bistable spring.
7. Valve according to one of Claims 1 to 6, characterized in that the closure in the environment tube is constituted by a disk valve which is under spring pressure.
8. Valve according to one of claims 1 to 7, characterized in that the upper surface of the membrane is covered by a cover, and in that the internal space formed thereby between the membrane and the cover is connected through a channel with the outlet of the safety valve.
9. Valve according to one of the claims 1 to 8, characterized in that the mouth of the channel at the outlet is included in the sealing seat of the disk valve seat, so that both the outlet and the outlet are closed by means of the disk valve. the channel.
10. Valve according to one of claims 1 to 9, characterized in that an intermediate wall with a check valve, in particular a mushroom-like membrane, is incorporated into the internal space between the membrane and the lid, and because the adjacent space formed by the The lid and the intermediate wall is connected through an adjacent channel with the outlet tube, wherein at least one throttling groove or the like is provided on the sealing surface of the mushroom-like membrane.
11. 11. Valve according to one of claims 1 to 10, characterized in that the valve body is configured as a depression in the region of the closure of the surrounding pipe. Valve according to one of Claims 1 to 11, characterized in that a gas blocking wall is provided above the depression.