Valve device, particularly a ventilation valve for the vent pipe of a vehicle fuel tank

Valve device, comprising a valve housing (1) with an inlet (3) and an outlet (5), a valve seat (13) and a valve closing member (8) movable in the housing between open and closed positions and having a sealing surface, which in the closed position of the valve closing member (8) is in contact with the valve seat to prevent liquid from flowing through the outlet. The valve closing member interacts with structure (15, 17) which, responsive to tilting of the valve housing relative to a predetermined position, moves the valve closing member to its closed position. The valve closing member being fixed to a float (11), which, as the liquid level rises in the housing (1) in its predetermined position, lifts the valve closing member towards its closed position, the weight of the structure (15, 17) being adapted to the lifting force of the float, so that the valve body, when the housing is filled with liquid and has been turned 180.degree. from the predetermined position, is held in its closed position. The valve closing member (8 ) is coordinated with a movably mounted plunger element (17), which is disposed at a certain liquid flow through the inlet (3) to lift the valve closing member to its closed position. The plunger element (17) forms a seat (16) on which rests a ball (15), on which ball (15) the valve closing member (8) rests. The seat is formed so that the ball lifts the valve closing member towards the valve seat (13), when the valve housing (1) is tipped from its predetermined position.

The present invention relates to a valve device comprising a valve housing 
with an inlet and an outlet, a valve seat and a valve closing member 
movable in said housing between open and closed positions and having a 
sealing surface, which in the closed positions of the valve closing member 
is in contact with the valve seat to prevent liquid from flowing through 
the outlet, said valve closing member interacting with said means which at 
a certain tilting of the valve housing, relative to a predetermined 
position, move the valve closing member to its closed position. 
A valve of this type is used, for example, as a so-called "roll-over" valve 
in the vent pipe between a vehicle fuel tank and a filter with activated 
charcoal, which is designed to absorb gasoline fumes from the tank. The 
valve is designed to prevent liquid gasoline from reaching the filter 
should the inclination of the vehicle exceed 30.degree., for example, 
since liquid gasoline impairs the capacity of the charcoal to absorb 
gasoline fumes. 
When filling the tank, some of the venting normally takes place via the gap 
between the gasoline pump nozzle and the tank fill pipe. If this gap is 
closed for the purpose of entirely preventing gasoline fumes from leaking 
out into the surrounding air, the entire volume of gas which is pressed 
out of the tank when it is filled with fuel must pass through the 
activated charcoal filter. Normally, when the tank is completely filled, 
the pump nozzle automatically shuts off the supply of fuel and prevent 
overfilling, but it is important that this automatic shut-off be effected 
quickly so that fuel does not rise in the vent pipe and reach the filter. 
If there is a seal between the nozzle spout and the tank fill pipe, then 
some form of safety device is required to protect against fuel penetrating 
to the filter. This protection can be in the form of a float operated 
valve in series with the "roll-over" valve. 
The purpose of the present invention is to combine the function of the 
"roll-over" valve and the float operated valve in a single, simple and 
reliable valve. 
This is achieved according to the invention in a valve device of the type 
described by way of introduction by virtue of the fact that the valve 
closing member is fixed to a float, which, as the liquid level rises in 
the housing in its predetermined position, lifts the valve closing member 
towards its closed position, and the weight of said means is adapted to 
the lifting force of the float, so that the valve body, when the housing 
is filled with liquid and has been turned 180.degree. from the 
predetermined position, is held in its closed position. 
If a float operated valve is turned upside down, the float will function in 
a way which is just the opposite to what was intended, i.e. with the float 
housing filled with liquid, the float will strive to keep the valve 
closing member from the valve seat. This means that if a car should turn 
over and come to rest upside down, the float would normally keep the valve 
open and allow gasoline to flow out through the vent pipe, but by adapting 
the components of the valve to each other in the manner stated above, the 
"roll-over" function will always predominate if the car should roll over. 
When filling the tank with fuel, a mixture of air and fumes flows out from 
the tank via the vent pipe. As soon as the tank is full, fuel rises in the 
vent pipe. If the filling is done relatively slowly, the float follows the 
rising of the liquid level in the valve housing and the valve closes 
without any liquid having forces its way through the valve outlet. If, 
however, the tank is filled rapidly, there is a "pressure surge" in the 
fuel, when the tank has been filled, and the float cannot close the valve 
quickly enough to prevent a certain amount of fuel from passing through 
the valve and reaching the filter. 
In order to make sure also that the valve closes when there is such a fuel 
pressure surge, according to a further development of the valve according 
to the invention, the valve closing member is coordinated with a movably 
mounted plunger element which is disposed, at a certain liquid flow 
through the inlet, to lift the valve closing member to the closed position 
.

In the FIGURE, 1 generally designates a valve housing, consisting of a 
lower housing portion 2 and an inlet stub 3, intended to be connected to a 
vent pipe from a fuel tank, and an upper housing portion 4 with an outlet 
stub 5, intended to be connected to a charcoal filter. The inlet stub 3 
has a cylindrical extension 6 which extends into the housing portion 2 and 
has four evenly distributed openings 7, through which gas or liquid can 
flow into the valve housing. A valve closing member 8 consists of a 
disc-shaped sealing portion 9 and a cylindrical portion 10 extending 
downwards therefrom, which is vertically displaceable in the housing. The 
cylindrical portion 10 is guided by the cylindrical extension 6 and 
carries on its outer surface an annular float 11. 
In the position shown, the valve is open, i.e. the valve closing member 8 
is in a lower end position, in which a sealing ring 12 on the valve disc 9 
is spaced from a conically shaped valve seat 13 in the housing portion 4. 
The underside of the valve disc 9, which is made with a conical depression 
14, rests in this position on a ball 15, which in turn rests in a conical 
depression 16 in a plunger element 17, which is slideably mounted in the 
cylindrical extension 6. The plunger element 17 is a homogeneous metal 
body to provide a relatively heavy weight. It has an upper shoulder, which 
in the rest position shown rests on the upper edge of the cylinder 6. 
With the movable components of the valve assuming the positions shown in 
the FIGURE, this occurring when the inlet 3 and the outlet 5 are 
vertically aligned and the valve housing is empty of liquid, gases can 
pass through the valve thus venting the fuel tank as it is filled. If fuel 
should penetrate into the valve housing, the valve closing element 8 will 
be lifted by the float 11, so that the sealing ring 12 of the valve disc 
will be pressed against the valve seat 13 thus closing the valve. This 
presupposes that the liquid level rises relatively slowly in the valve 
housing. If the fuel tank is filled rapidly, the fuel will surge through 
the vent pipe when the tank is completely filled. The openings 7 in the 
cylinder 6 serve in this case as constrictions and the plunger 17 will be 
subjected at its lower end surface to an upwardly directed force caused by 
a rapid pressure surge in the space below the plunger 17. This results in 
the plunger rapidly lifting the valve closing member 8 to a closed 
position. This process is substantially more rapid than closing by the 
effect of the float alone. When the valve has been closed and the pressure 
equalized on either side of the plunger due to the valve housing being 
filled with fuel, the plunger 17 returns to its starting position and the 
valve is kept closed by the float 11 as long as there if fuel in the valve 
housing. 
When the valve housing 1 is tipped from its position shown, the ball 15 
rolls out (up) towards the edge of the conical depression 16, thus lifting 
the valve closing member 8 towards the valve seat 13, whereby the valve is 
completely closed, for example when the angle of tilt exceeds 30.degree.. 
By virtue of the fact that the valve disc 9 also has a conical depression 
14 on its underside, against which surface the ball rolls, a double 
lifting height is obtained compared with the case with a valve disc with a 
flat underside. 
If the valve is turned over 180.degree. from the position shown, meaning 
that the car has come to rest upside down, the valve closing member 8 is 
loaded by the combined weight of the ball 15 and the plunger 17. Their 
masses are selected so that the float 11, under the influence of fuel 
flowing into the valve housing, is not able to lift the valve body from 
the closed position, i.e. the combined weight of the valve closing member 
8, the ball 15 and the plunger 17 is greater than the lifting force of the 
float 11. 
The plunger element 17 thus has a double function. It serves on one hand as 
an "emergency" valve closing device actuated by a pressure surge and, on 
the other hand, as a member whose weight helps to counteract the lifting 
force of the float 11 when the valve is turned upside down.