Flow valve or shut-off cock for flow networks with sealing means

A flow valve or shut-off cock for flow networks having sealing means of particular features which make its design easy and increase its tightness and useful life. This valve provides sealing means reacting in proportion to the flow pressure, for which purpose sealing means of the lung type are available, that is to say, the sealing means consist in a flexible and hollow body, which is inflated by the flow pressure going into the valve, pressing one of the walls of the flexible element against the opening of the valve intended to be blocked or obstructed. This sealing element of the lung type is controlled by the rotation of a rigid stem component partially surrounding it in its upper zone and in external side areas.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention is related to a flow valve or shut-off cock for flow networks 
with sealing means of particular features which make its design easy and 
increase its tightness and useful life. 
2. Description of the Related Art 
Several designs of flow valves are known, which have tried to simplify 
their manufacture and increase the tightness, but most of them loses their 
efficiency before working pressures higher than the normal ones. There are 
others, which, although reducing the number of components making up the 
valve (which facilitates the assembly of them), must make use of complex 
geometry which make die making more expensive. 
A group of known valve designs, such as that under patent U.S. Pat. No. 
3,974,869, consists in an elastic envelopment around a rigid stem which 
acts as the core of the system. The efficiency of these valves depends on 
the quality of the material with which the elastic component is 
manufactured, and makes it necessary a very accurate construction of the 
components in order to ensure a suitable fit among them and a low friction 
coefficient. Notwithstanding this, and due to the fact that the sealing 
means of these valves are independent from the flow pressure, the pressure 
exerted by the sealing means against the inner walls of the valve is 
constant and generates unnecessarily high friction forces, although flows 
with low pressures are controlled, which reduces their useful life. 
Another disadvantage of these valves is related to the restrictions caused 
by the election of materials of the valve body in order to ensure that 
their coefficient of thermal expansion be lower than the coefficient of 
thermal expansion of the sealing elements. 
Another type of valve known is that under patent U.S. Pat No. 3,814,120, 
which is very complex due to the number and shape of its components. The 
quality of the sealing effect is constant, showing problems at high 
pressure ranges. 
The sealing elements of the known valves mainly act on a measure exceeding 
the same with respect to the sizes of the valve body, the compression 
forces of the sealing material being those which exercise the sealing 
function itself. According to this, these designs of valve demand the 
existence of an element of inner rigid stem in the sealing element acting 
as supporter. 
SUMMARY OF THE INVENTION 
On the contrary, the valve under this invention offers sealing elements 
proportionally reacting to the flow pressure. 
In schematic terms, the invention is based on providing sealing means of 
the lung type, that is to say, the sealing means consist in a flexible and 
hollow body, which is inflated by the flow pressure going into the valve, 
pressing one of the walls of the flexible element against the opening of 
the valve intended to be blocked or obstructed. This sealing element of 
the lung type is controlled by making a rigid stem component to rotate 
partially surrounding it in its upper zone and in external side areas. 
The valve of the invention is basically made up of a substantially 
traditional valve body and a cylindrical stem composed of two parts: an 
upper component which is rigid, and a lower component formed by an 
elastomeric material. 
The upper component of the stem is cylindrical and rigid with the shape of 
an inverted cup. Its mantle shows at least four openings in its medium 
line. 
The lower component of the stem is flexible and abuts in the inner lower 
part of the rigid component of the stem, so that at least three of its at 
least four openings are partially blocked by the flexible body and the 
fourth opening of the rigid component is totally blocked by said flexible 
body. 
With the structure of valve already described, a cylindrical and hollow 
stem in its lower part is obtained, which defines a chamber to which the 
flow accesses through one of the openings existing in the medium line of 
its mantle. These openings innerly top out in flexible blocks, which allow 
the dragging of the flexible body when the rigid stem rotates. In 
addition, the compound stem mantle shows a (closing) flexible block 
projecting out of the mantle in a location in which it shall be in front 
of one of the flow outlets in the body of the valve. This flexible closing 
block shall fit to the flow outlet when the stem is aligned in a closing 
position due to the pressure exerted by the flow when entering the stem 
chamber through one of the openings.

DETAILED DESCRIPTION OF INVENTION 
As shown in FIGS. 1 through 6, a two-way valve, according to the invention, 
consists in a valve body 1 of the standard type, which, in this example, 
has a flow inlet 2 and a flow outlet 3 laid out in 180.degree.. A 
preferably cylindrical stem fits inside cavity 4 of the valve body 1, 
which has a rotation freedom of 90.degree.. This stem is made up of a 
rigid component 5 and a flexible component 6. 
The rigid stem component 5 has the traditional elements in its upper end to 
hold it in the valve body t and to fix an actuator to it. The lower part 
of the rigid stem component 5 has a particular structure, which is formed 
from a portion of the cylindrical mantle 7, opened in its lower basis. 
This portion of cylindrical mantle 7 of the rigid stem has two kinds of 
openings extending up to the lower end of said mantle. A first group of 
these openings consist in three openings 8, 9 and 10, which begin at the 
mantle level corresponding to the inlet level 2 and in outlet 3 of the 
flow of the valve body 1, which purpose is to lead the flow, whether this 
is going into or out of the stem assembly. A second group of openings 
consists in a single opening 11 which begins above the inlet and outlet 
level of flow, extending up to the lower end of the cylindrical mantle 7 
and which purpose is to accommodate an obstruction seal projection (16) of 
the flexible component 6 of the stem. 
Openings 8, 9 and 10 are located in successive quadrants of the cross 
section of the cylindrical mantle 7 and opening 11 is located in the 
remaining quadrant. 
Both the cavity defining the cylindrical mantle 7 and its four openings 8, 
9, 10 and 11 have the purpose of accommodating and holding the component 
of flexible stem 6, which consists in a hollow body, opened in the bottom 
and having three holes 12, 13 and 14--circular preferably--which fit with 
the upper zone of openings 8, 9 and 10 of the rigid stem component 5, 
respectively, so that they have a geometry and dimensions which are 
substantially similar to the geometry and dimensions of the flow inlet 
windows 2 and flow outlet windows 3 located in cavity 4 of the valve body 
1. Immediately below each one of holes 12, 13 and 14, there are three 
corresponding risings of projections 15, which main purpose is to work as 
dragging elements for the simultaneous rotation of the flexible component 
6 when the rigid component 5 is rotated. In addition, the component of the 
flexible stem 6 has an obstruction seal projection 16 which completely 
fills the opening 11 of the portion of the cylindrical mantle 7, slightly 
projecting with respect to said mantle. This projection comprises an area 
in the mantle of the rigid stem components exceeding the area of flow 
outlet opening in the wall cavity 4 of the valve body. 
The flexible stem component 6 also has an upper projection 17, which fits 
to the upper inner pad of the rigid stem 5, but, in order to facilitate 
the placement of said flexible component and avoid the formation of an air 
bubble, the upper projection has longitudinal recesses 18 (which may be 
replaced with a hole communicating the upper face of projection 17 with 
its lower face). FIG. 7 shows the space formed between the flexible stem 
component 6 and the inner wall of the rigid stem 5. 
The elements described define as a whole a valve with a hollow stem and 
opened in the bottom, which is made up of a rigid component 5 and an 
elastomeric compound 6, which defines a chamber of elastic walls capable 
of being deformed due to the effect of flow pressure. This deformation 
takes place in the only element of the flexible component 6 which is 
subject to a difference in pressure, which is its obstruction seal 
projection 16, when the latter is in front of some outlet opening, such as 
opening 3. According to this arrangement, the elastic deformation of the 
obstruction seal projection 16 is positive, that is to say, the flow 
pressure makes this projection 16 to compress against the outlet opening 3 
sealing it with a force proportional to the flow pressure, as shown in 
FIGS. 4 and 6. 
As already stated, the valve of this invention seals in a form which is 
proportional to the flow pressure. Notwithstanding this, when the flow 
pressure is very low, the elastic features which are inherent in the 
elastomeric material making up the component of flexible stem 6, together 
with its surplus projecting out of the mantle, shall exert a sealing 
pressure against the edges of the flow outlet opening in cavity 4. 
In FIGS. 4, 6 and 9, the situation of the closed two-way valve is depicted, 
so that the obstruction seal projection 16 is in front of the outlet 
opening 3 of the valve body 1. When the stem assembly rotates by 
90.degree.(counterclockwise according to drawings), the two-way valve 
allows the passing of flow (see FIGS. 3, 5 and 8) due to the fact that the 
obstruction seal projection 16 is now in a position in which it does not 
hinder the flow inlet 2 or outlet 3, these ways becoming in front of 
openings 10-14 and 8-12 of the stem assembly. 
It is possible that opening 9 of the rigid stem component 5 and opening 13 
of the flexible stem component 6 do not exist in the version of the 
two-way valve, but due to manufacture reasons, it is more practical to 
manufacture an universal stem assembly, such as that described and 
depicted, which shall work both for two-way valves and three-way valves, 
the same stem assembly being able to be used in 3-way valves by 90.degree. 
and in 3-way valves by 180.degree., depending on the quantity and location 
of the inlets and outlets of the body valve. 
From this first example, certain obvious variants of the invention may be 
mentioned, depending on the number of outlets with which the valve body is 
equipped and on the rotation freedom level of the compound stem. 
Should the valve body have two outlets and the compound stem may only 
rotate 90.degree., then a flow-switching valve exists, so that when an 
outlet is opened, the other one is closed. 
Should the valve body have two outlets and the compound stem may rotate 
180.degree., then we have a valve which can have three conditions: a first 
condition with the first outlet opened and the second outlet closed; a 
second condition inversely to the previous one, that is, with the first 
outlet closed and the second one opened; a third condition with both 
outlets opened. 
In all cases, the valve shall have traditional stops which limit the 
rotation of the stem in order to prevent that the seal projection 16 is in 
front of the flow outlet, since, as already told, this seal projection 
shall work with a positive pressure which presses it against the 
corresponding flow outlet. 
Notwithstanding that stated with respect to the modality of valve depicted 
in FIGS. 1 through 6, the lower openings of the stem compounds might not 
exist, but their existence facilitates the manufacture and allows to use 
the stem with other valve bodies having a lower flow inlet. 
A second example of the flow valve using the same compound of the previous 
modality is shown in FIGS. 10 through 13. This valve consists in a lower 
flow inlet 20 with three flow outlets 31, 32 and 33 located in the medium 
plane of the valve body and orthogonally distributed. In FIGS. 10 through 
13, only the flow inlet 20 and outlets 3t, 32 and 33 have been depicted, 
the valve body as such being omitted in order to facilitate the 
visualization of the compound stem in its different positions with respect 
to the flow outlets. The compound stem of this valve has a rotation 
freedom of 360.degree., that is to say, the valve body has not limiting 
stops for the rotation stroke of the stem. 
In FIG. 10 the valve with a compound stem oriented in a first rotation 
position is shown, so that the seal projection 16 of the flexible stem 6 
is not obstructing any of the three flow outlets 31, 32 and 33. Flow inlet 
20 is permanently in front of the lower opening 40 of the flexible stem 6 
which is communicated with openings 8, 9 and 10 of rigid stem 5, said 
openings being--in this first rotation position of the compound stem--in 
front of the flow outlets 31, 32 and 33, respectively, the valve thus 
becoming in conditions to provide a free outlet of flow through its three 
outlet ducts. 
In FIG. 11 a valve with the compound stem oriented in a second rotation 
position is shown, so that the seal projection 16 of the flexible stem 6 
is obstructing the flow outlet 31. Openings 9 and 10 of rigid stem 5--in 
this second rotation position of the compound stem--are in front of the 
flow outlets 33 and 32, respectively. Opening 8 of rigid stem 5 is not in 
front of any outlet opening. In this condition the valve becomes to 
provide a free outlet of flow through its outlet ducts 32 and 33 and the 
outlet duct 31 is obstructed. 
In FIG. 12 a valve with the compound stem oriented in a third rotation 
position is shown, so that the seal projection 16 of the flexible stem 6 
is obstructing the flow outlet 32. Openings 8 and 10 of rigid stem 5--in 
this third rotation position of the compound stem--are in front of the 
flow outlets 31 and 33, respectively. Opening 9 of rigid stem 5 is not in 
front of any outlet opening. In this condition the valve becomes to 
provide a free outlet of flow through its outlet ducts 31 and 33 and the 
outlet duct 32 is obstructed. 
In FIG. 13 a valve with the compound stem oriented in a fourth rotation 
position is shown, so that the seal projection 16 of the flexible stem 6 
is obstructing the flow outlet 33. Openings 8 and 9 of rigid stem 5--in 
this fourth rotation position of the compound stem--are in front of the 
flow outlets 32 and 31, respectively. Opening 10 of rigid stem 5 is not in 
front of any outlet opening. In this condition the valve becomes to 
provide a free outlet of flow through its outlet ducts 31 and 32 and the 
outlet duct 33 is obstructed. 
From this second example which considers a lower inlet of flow, certain 
obvious variants of the invention may be stated, depending on the number 
of outlets with which the valve body is equipped and depending on the 
level of rotation freedom of the compound stem. 
Should the valve body has an outlet and the compound stem may rotate only 
90.degree., then we have a flow valve of the cock and fitting type. 
Should the valve body has two outlets at 90.degree. and the compound stem 
may rotate 90.degree., then we have a valve which may have two conditions: 
a first condition with the first outlet opened and the second outlet 
closed, and a second condition inverse to the previous one, that is, with 
the first outlet closed and the second outlet opened. 
Should the valve body has two outlets at 90.degree. and the compound stem 
may rotate 180.degree., then we have a valve which may have three 
conditions: a first condition with the first outlet opened and the second 
outlet closed; a second condition inverse to the previous one, that is, 
with the first outlet closed and the second outlet opened; and a third 
condition with both outlets opened. 
Should the valve body has two outlets at 180.degree. and the compound stem 
may rotate 180.degree., then we have a valve which may have three 
conditions: a first condition with the first outlet opened and the second 
outlet closed; a second condition with both outlets opened and a third 
condition inverse to the first one, that is, with the first outlet closed 
and the second outlet opened.