Valves and valve actuation – Fluid actuated or retarded – Fluid and non-fluid actuators
Reexamination Certificate
2001-01-16
2002-07-02
Doerrler, William C. (Department: 3754)
Valves and valve actuation
Fluid actuated or retarded
Fluid and non-fluid actuators
C251S077000, C251S129110, C251S251000, C251S259000, C251S279000
Reexamination Certificate
active
06412750
ABSTRACT:
TECHNICAL FIELD
The present invention relates, in general, to a valve system for fluid pipes and, more particularly, to an improvement in such a valve system to allow the system to be operable using pneumatic pressure or using another means in place of pneumatic pressure and to be controlled easily and precisely, and to quickly and smoothly feed fluid, thus improving operational reliability of the system.
BACKGROUND ART
As well known to those skilled in the art, a fluid pipe, used for feeding fluid, is provided with one or more valve systems for controlling the flow of fluid passing through the pipe.
FIGS. 1 and 2
show the construction and operation of a conventional pneumatic valve system for fluid pipes. As shown in the drawings, the conventional valve system comprises two bodies: first and second bodies
11
and
12
assembled into a single valve housing
10
. An internal fluid passage
13
is longitudinally formed along the central axis of the valve housing
10
with inlet and outlet openings
13
a
and
13
b
being provided at both ends of the passage
13
. In such a case, the inlet opening
13
a
is formed in the first body
11
, while the outlet opening
13
b
is formed in the second body
12
. An annular guide groove
13
c,
having a concave surface, is formed on the passage
13
at a position inside the outlet opening
13
b.
A cylindrical valve body
20
, having an axial fluid passing opening
21
, is axially and movably fitted in the passage
13
in a way such that the valve body
20
is reciprocable within a predetermined range in the axial direction of the valve housing
10
. The above valve body
20
selectively closes the passage
13
at the first end
22
thereof when the valve body
20
is fully moved to the right in the drawings. That is, the first end
22
of the valve body
20
acts as a passage control means for opening or closing the passage
13
of the valve system. A flanged cylindrical disc
30
, having two fluid passing holes
31
on its sidewall, is fixedly installed in the passage
13
at a position within the guide groove
13
c.
The reciprocable valve body
20
selectively comes into close contact with the flange of the disc
30
at the first end
22
when the valve body
20
is fully moved to the right in the drawings, thus closing the passage
13
.
An annular pressure actuated flange
25
is exteriorly and fixedly formed on the valve body
20
. The above flange
25
formes first and second air pressure chambers
15
a
and
15
b
within the valve housing
10
at opposite sides thereof while sealing the junction between the two variable chambers
15
a
and
15
b.
The first chamber
15
a
is provided with a first air injection port
16
a,
through which pneumatic pressure, or external air pressure, is injected into the chamber
15
a
so as to open the passage
13
. The second chamber
15
b
is provided with a second air injection port
16
b,
through which external air pressure is injected into the chamber
15
b
so as to close the passage
13
.
A fluid flow control operation of the above valve system will be described hereinbelow.
In order to open the passage
13
of the valve system, external air pressure is injected into the first chamber
15
a
through the port
16
a, thus acting on the right-side surface of the pressure actuated flange
25
. The valve body
20
is thus moved toward the fluid inlet opening
13
a,
and so the first end
22
of the valve body
20
is spaced apart from the disc
30
. Therefore, the internal fluid passage
13
of the system is opened as shown in FIG.
1
.
When the passage
13
is opened as described above, fluid, introduced into the passage
13
through the inlet opening
13
a,
flows into the groove
13
c
through the gap between the valve body
20
and the disc
30
. The fluid, thereafter, passes through the fluid passing holes
31
of the disc
30
prior to being discharged from the passage
13
through the outlet opening
13
b.
When it is necessary to close the passage
13
of the valve system, external air pressure is injected into the second chamber
15
b
through the port
16
b,
thus acting on the left-side surface of the flange
25
. The valve body
20
is thus moved toward the fluid outlet opening
13
b,
and so the first end
22
of the valve body
20
comes into close contact with the disc
30
. Therefore, the internal fluid passage
13
of the system is completely closed as shown in FIG.
2
.
When the passage
13
is closed as described above, fluid, introduced into the passage
13
through the inlet opening
13
a,
is prevented from flowing into the groove
13
c.
It is thus impossible for the fluid to be discharged from the passage
13
of the valve system into a pipe through the outlet opening
13
b.
However, the above valve system is problematic in that the valve body
20
is designed to be only pneumatically operated, thus failing to be precisely controlled. It is thus impossible to precisely control the opening of the valve body
20
.
The above valve system is not provided with any separate means for controlling the valve body
20
, the means being selectively used for actuating the valve body
20
in an emergency case wherein it is impossible to get air pressure. This reduces the operational reliability and market competitiveness of the valve system.
In addition, the valve body
20
is brought into frictional contact with the interior surface of the passage
13
during a reciprocating action thereof. Therefore, it is difficult for the valve body
20
to smoothly move within the passage
13
, and so the valve body
20
may fail to accomplish a desired operation. This problem becomes worse when the air pressure, acting on the flange
25
of the valve body
20
, is less than a reference level.
Another problem, experienced in the above valve system, is caused by a difference in flow rates between fluid currents within the passage
13
. That is, the outside fluid current, flowing along the interior surface of the passage
13
, may be easily and smoothly introduced into the guide groove
13
c
at a relatively high speed. However, the central fluid current, flowing along the axis of the passage
13
, may be not easily or smoothly introduced into the groove
13
c.
This is caused by the fact that there occurs a friction between the central fluid current and the disc
30
and the central fluid current has to be moved from the central portion of the passage
13
to the guide groove
13
c.
Therefore, the flow rates of the fluid currents are different from each other. Due to such a flow rate difference, it is almost impossible for the fluid to quickly or smoothly flow in the passage
13
.
DISCLOSURE OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a valve system for fluid pipes, which is designed to be operable using pneumatic pressure or using another means in place of pneumatic pressure and is designed to be controlled easily and precisely.
Another object of the present invention is to provide a valve system for fluid pipes, which effectively reduces the frictional force between relatively moved parts during an operation of the system, thus being allowed to be easily and smoothly operated.
A further object of the present invention is to provide a valve system for fluid pipes, which allows fluid to smoothly and quickly pass through the system.
In order to accomplish the above objects, the present invention provides a valve system having the following construction. Both a disc and a reciprocable valve body are provided within the internal fluid passage of a valve housing, with fluid inlet and outlet openings being formed at both ends of the passage. The valve body is designed to be normally and pneumatically operated using air pressure injected into either one of two chambers, provided at both sides of the pressure actuated flange of the valve body, through first or second injection port of the valve housing in the same manner as that of the prior art. The valve body thu
Do Yung Gee
Jun Duck Jo
Bonderer David A
Doerrler William C.
Lowe Hauptman & Gilman & Berner LLP
Se Woo Conval Co., Ltd.
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