Title: Quick closing shut-off valve
Abstract: A quick closing shut-off valve includes an inlet, an outlet and a passage there between. A closing element blocks the passage when in the closed position. The closing element is interconnected to a piston via a pull rod. The piston is positioned within a working chamber that communicates with the valve outlet. A safety valve also communicates with the working chamber and is positioned above the piston. As a result, when the pressure within the tank, and thus in the working chamber, reaches a maximum permissible pressure, the safety valve opens and the pressure above the piston decreases. The piston rises as a result and pulls the closing element via the pull rod into the closed position so that the valve is closed.
Patent Number: 7,025,083 Issued on 04/11/2006 to Chrz, et al.
| Inventors:
|
Chrz; Vaclav (Usti nad Labem, CZ);
Kirchgassner; Gerd (Decin, CZ);
Zaruba; Petr (Decin, CZ)
|
| Assignee:
|
Chart Inc. (Burnsville, MN)
|
| Appl. No.:
|
222263 |
| Filed:
|
August 15, 2002 |
Foreign Application Priority Data
| Aug 16, 2001[CZ] | 2001-2998 |
| Current U.S. Class: |
137/492; 137/115.13; 137/461; 137/613; 251/63 |
| Current Intern'l Class: |
F16K 31/12 (20060101) |
| Field of Search: |
137/11513,115.23,115.26,71,461,492,509,613,462
251/63
62/507
|
References Cited [Referenced By]
U.S. Patent Documents
| 333403 | Dec., 1885 | Fitts.
| |
| 615812 | Dec., 1898 | Dallett.
| |
| 618903 | Feb., 1899 | Prince.
| |
| 784961 | Mar., 1905 | Parsons.
| |
| 871260 | Nov., 1907 | Dyer.
| |
| 1288578 | Dec., 1918 | Hatfield et al.
| |
| 1628698 | May., 1927 | Walker.
| |
| 2928410 | Mar., 1960 | Del Vecchio.
| |
| 3774628 | Nov., 1973 | Norton et al.
| |
| 3776251 | Dec., 1973 | Trubman.
| |
| 3904175 | Sep., 1975 | Deschenes.
| |
| 4171004 | Oct., 1979 | Cerrato et al.
| |
| 4171708 | Oct., 1979 | Pareja.
| |
| 4244388 | Jan., 1981 | Feiss.
| |
| 5398719 | Mar., 1995 | Drossel et al.
| |
| 6382235 | May., 2002 | Drube et al.
| |
| Foreign Patent Documents |
| 25 50 558 | May., 1977 | DE.
| |
| 100 11 674 | Jun., 2001 | DE.
| |
| 2 355 510 | Apr., 2001 | GB.
| |
Primary Examiner: Krishnamurthy; Ramesh
Attorney, Agent or Firm: DLA Piper Rudnick Gray Cary US LLP
Claims
What is claimed is:
1. A device for over-pressure protection of a tank during filling with a liquid, comprising:
a main body with an inlet that leads to an inlet chamber, an outlet that leads
to an outlet chamber, and a valve seat having an opening that defines a passage
therein, wherein the passage interconnects the inlet chamber to the outlet chamber,
said main body also featuring a working chamber and an open section in communication
with the working chamber;
a closing element disposed within said main body and movable between an open
position where liquid may flow through the passage and a closed position where
the closing element engages the valve seat so that liquid is prevented from flowing
through the passage; and
a piston movably disposed within a working chamber within the main body and connected
to the closing element by a pull rod, said working chamber in communication with
the outlet chamber so that said piston is adapted to communicate with the tank
through the main body outlet so that the closing element is moved between the open
and closed positions in response to a pressure change within the tank; and
said piston sized smaller than said working chamber so that fluid may pass between
the piston and sidewalks of the working chamber into the open section.
2. The device of claim 1, wherein the closing element is a plate.
3. The device of claim 1, wherein the closing element is disposed in the inlet
chamber and the pull rod passes through the passage of the valve seat.
4. The device of claim 3 wherein the outlet chamber communicates with the working
chamber through an annular gap surrounding the pull rod.
5. The device of claim 4 further comprising a pressure relief device in communication
with the open section.
6. The device of claim 5 wherein the pressure relief device is a safety valve.
7. The device of claim 5 wherein the pressure relief device is a rupture disk.
8. The device of claim 1 further comprising a channel in communication with the
outlet chamber and the working chamber.
9. The device of claim 1 further comprising a pressure relief device in communication
with the open section.
10. The device of claim 9 wherein the pressure relief device is a safety valve.
11. The device of claim 9 wherein the pressure relief device is a rupture disk.
12. The device of claim 1, wherein the open section has a larger cross sectional
area than the working chamber.
13. The device of claim 12 further comprising a pressure relief device in communication
with the open section.
14. The device of claim 13 wherein the pressure relief device is a safety valve.
15. The device of claim 13 wherein the pressure relief device is a rupture disk.
16. A device for protecting a tank from over-pressurization during filling with
a liquid from a source comprising:
a main body having an inlet adapted to communicate with the liquid source, an
outlet adapted to communicate with the tank and a passage there between;
a closing element positioned within the main body and movable between an open
position where liquid may pass through the passage and a closed position where
the closing element blocks the passage so that liquid is prevented from passing
there through;
a piston movably positioned within a working chamber in the main body, said piston
sized smaller than said working chamber so that fluid may pass between the piston
and sidewalks of the working chamber;
a pull rod connecting the piston to the closing element;
a pressure relief device in communication with the working chamber above the
piston and set to open at a predetermined maximum pressure;
said working chamber in communication with the outlet so that when the predetermined
maximum pressure is reached in the tank, the pressure in the working chamber also
reaches the predetermined maximum pressure so that the pressure relief device opens
and pressure above the piston is reduced so that the piston rises and moves the
closing element to the closed position.
17. The device of claim 16 further comprising an open section having a larger
cross sectional area than the working chamber and in communication with the working
chamber and the pressure relief device.
18. The device of claim 16 wherein the pull rod passes through the passage.
Description
REFERENCE TO RELATED APPLICATIONS
This application claims priority to Czech Republic Patent Application Number
PV 2001-2998, filed with the Board of Industrial Property of the Czech Republic
on Aug. 16, 2001.
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to the filling of storage tanks with
fluids and, more particularly, to a device that prevents over-pressurization of
storage tanks while they are being filled with fluids.
BACKGROUND OF THE INVENTION
It is necessary to protect a pressure vessel or storage tank from over-pressurization
when filling the pressure vessel with a liquid from a source that is capable of
achieving a higher pressure than the maximum permissible pressure of the vessel
or storage tank.
Pressure vessels are equipped with pressure relief devices such as relief
valves or rupture disks which are activated when the maximum permissible pressure
in normal operation is exceeded or when other unfavorable conditions exist. A pressure
relief device maintains the pressure in a vessel at the permissible level by discharging
fluid from the vessel when the pressure setting of the pressure relief device is
exceeded. The liquid source, for example a tank truck that delivers and dispenses
liquids, however, may supply an excess amount of fluid at a high pressure such
that the relief valves are not capable of protecting the vessel from the excessive pressure.
Liquefied gases, such as liquid nitrogen, oxygen, argon, methane, carbon
dioxide and others, are stored and transported at low temperatures. Typically,
the liquefied gases are stored and transported in pressure vessels equipped with
vacuum or foam insulation and a relief valve or rupture disk pressure relief device.
In addition to the issues stated above, the pressure relief devices are unable
to relieve the pressure generated in the top of the vessel and relief piping, which
is due to vapor produced by evaporation of the liquid as it is delivered to the
vessel by a highly powerful pump, when the vessel becomes completely filled with
pressurized fluid. Such powerful pumps may be found on some tank trucks. In each
of the above instances, it is crucial to avoid exceeding the maximum permissible
pressure of the vessel. This may be achieved by closing the filling piping and/or
reducing the flow rate of the fluid from the source into the filled pressure vessel.
As such, a quick closing shut-off valve is desirable.
Quick closing shut-off valves are installed at the inlet of pressure vessels
to protect the pressure vessels against over-pressurization by closing when the
pressure in the vessel exceeds a predetermined level. Quick closing shut-off valves
are particularly useful with storage tanks for cryogenic liquids due to the high
pressure and high flow rate pumps mounted on many cryogenic liquid tank trucks
and also due to the expansion of the cryogenic fluids which occurs due to evaporation
as they flow to the vessel being filled.
A common type of prior art quick closing shut-off valve, however, is fitted with
a compressed spring that is secured with a latch. The latch is released when the
pressure in the vessel reaches the maximum level to shut-off the flow of the fluid
into the vessel. Re-opening the flow of the fluid into the vessel requires re-compressing
the spring and locking the valve in the open position with the latch. This resetting
of the valve is time-demanding and requires special tools to compress the spring.
In addition, the design of this prior art quick closing shut-off valve is complicated
with passive resistances in the releasing mechanism that are not reliable.
German publication DIT 25 50 558 A1, German Patent No. DE 100 11 674 A1 and
United Kingdom published patent application number GB 2 355 510 illustrate valves
for reducing pressure, shutting off flow and regulating flow, respectively. Each
of the valves features a sliding piston or plunger that is housed within a valve
body. The valve body includes a liquid inlet and a liquid outlet. The piston or
plunger is moved to restrict or eliminate the flow of liquid from the valve inlet
to the outlet.
Each of the three valves, however, suffers from disadvantages with regard to
use in protecting pressure vessels. More specifically, the valve of German publication
DIT 25 50 558 A1 is not suitable for protecting pressure vessels where fast restoration
of operating conditions is desirable after relief of pressure from the vessel.
The closing of the valve of German Patent No. DE 100 11 674 A1 takes place magnetically
when a pressure decrease occurs. Conversely, the liquid flowing to the valve must
be at a certain pressure level to open the valve. Such an arrangement is not suitable
for protecting pressure vessels against excessive pressure. The valve of United
Kingdom published patent application number GB 2 355 510 is complicated and costly.
In addition, the valve requires a pressure impulse to open the valve. The creation
of such an impulse requires additional equipment capabilities.
Other known automatic shut-off valves have complicated mechanisms for shutting-off
fluid flow, usually including springs, balls or other moving parts that are difficult
to produce, wear quickly with use and require frequent maintenance.
As a result, the prior art quick closing valves suffer from a number of disadvantages
with regard to shutting off the flow of fluid, particularly of liquefied gases,
into a pressure vessel.
Accordingly, it is an object of the present invention to provide a quick
closing shut-off valve that automatically closes when the pressure in a vessel
being filled reaches a predetermined level.
It is another object of the present invention to provide a quick closing shut-off
valve that automatically opens when the pressure in a vessel decreases from the
predetermined level.
It is still another object of the present invention to provide a quick closing
shut-off valve that is economical to manufacture, operate and maintain.
SUMMARY OF THE INVENTION
A device for protecting a tank from over-pressurization while the tank is being
filled with a liquid includes a main body with an inlet that leads to an inlet
chamber and an outlet that leads to an outlet chamber. The body also includes a
valve seat with an opening that defines a passage therein. The passage interconnects
the inlet chamber to the outlet chamber. A closing element is movably positioned
within the inlet chamber. The closing element may be moved between an open position
for allowing the liquid to flow from the inlet to the outlet and a closed position
for blocking the flow of the liquid.
A piston is movably positioned within a working chamber of the main body. The
working
chamber includes an open section and a pressure relief device positioned above
the piston. The piston is connected to the closing element by a pull rod that passes
through the passage. The working chamber and open section communicate with the
outlet chamber and thus are pressurized by pressure increases in the tank. When
the pressure within the tank, and thus in the working chamber and open section,
reaches a predetermined maximum level, the pressure relief device opens decreasing
the pressure above the piston. As a result, the piston moves upwards and pulls
the closing element into the closed position so that the valve is closed.
For a more complete understanding of the nature and scope of the invention, reference
may now be had to the following detailed description of embodiments thereof taken
in conjunction with the appended claims and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a pressure vessel equipped with an embodiment
of the quick closing shut-off valve of the present invention where the vessel is
being filled by a tank truck;
FIG. 2 is an enlarged cross sectional view of the quick closing shut-off valve
of FIG. 1 in the open configuration; and
FIG. 3 is an enlarged cross sectional view of the quick closing shut-off valve
of FIG. 1 in the closed configuration.
DETAILED DESCRIPTION
Referring to FIG. 1, an embodiment of the quick closing shut-off valve
of the present invention is indicated at
10 and illustrated as installed
on the inlet valve
32 of a stationary storage tank
22. A transportable
supply tank
14 is positioned upon a truck
16 that also features an
inboard, high pressure, high flow rate, centrifugal transport pump
18. The
pump
18 runs a substance
19, such as a liquid cryogenic, from the
supply tank
14 through a feed or supply line
20, through the quick
closing shut-off valve
10 and into a storage tank
22. In addition
to the inlet valve
32, the storage tank
22 has relief valves
23
and an outlet valve
33 for dispensing the stored substance. The pump
18
may also be a stationary pump located by the storage tank site
22 rather
than inboard the truck
16.
The quick closing shut-off valve illustrated at
10 in FIG. 1, is indicated
in general at
10 in FIGS. 2 and 3 in the open and closed configurations,
respectively. The quick closing shut-off valve consists of a cylindrical body
101
having an inlet
106 and an outlet
108. With reference to FIG. 1,
the inlet
106 is in communication with the feed supply line
20 from
the truck
16 and the outlet
108 is in communication with the inlet
valve
32 of the storage tank
22.
As illustrated in FIGS. 2 and 3, the inlet
106 of the quick closing valve
leads to an inlet chamber
110. The bottom of the inlet chamber
110
is enclosed by an installation lid
118. The sides of the inlet chamber
110
are enclosed by the body
101 of the quick closing valve. The top of the
inlet chamber
110 is partially enclosed by a valve seat
107. The
valve seat
107 includes an opening
119, which defines a passage
120
therethrough. Thus the valve seat
107 reduces the top of the inlet chamber
110 to the size of the opening
119 in the valve seat
107.
The quick closing valve also includes a closing element
103 which is interconnected
to a piston
105 via a pull rod
104. The closing element
103
is shaped as a plate. The closing element
103 may also be formed in a different
shape, such as a cone or a ball. The closing element
103 is located within
the inlet chamber
110 and the pull rod
104 is positioned within the
center of the opening
119 of the valve seat
107.
As previously discussed, an installation lid
118 closes the inlet chamber
110 and the body
101 of the quick closing shut-off valve. The installation
lid
118 may be removed to provide easy access to the closing element
103
and the interior of the body
101 of the quick closing valve.
As illustrated in FIG. 2, when the valve is in the open configuration, the piston
105 is primarily positioned within a working chamber
116. The piston
is sized such that the piston
105 does not contact the side walls of the
chamber
116. In other words, there is some play between the piston.
105
and the side walls of chamber
116. Thus, the piston
105 is free to
move in a vertical direction with respect to the working chamber
116 and
fluid may pass between piston
105 and the side walls of chamber
116.
As illustrated in FIG. 3, the piston
105 rises from the working chamber
116 into an open section
115 which has a larger cross sectional area
than working chamber
116. As piston
105 rises, the pull rod
104
and closing element
103 are also raised. The piston
105 is raised
until the closing element
103 contacts the valve seat
107. Once the
closing element
103 contacts the valve seat
107, the opening
119
at the top of the inlet chamber
110, and thus passage
120, is plugged.
The open section
115 is fitted with a pressure relief device, such as
safety valve
102. The safety valve may be replaced by a rupture disc designed
to rupture when a maximum permissible pressure is reached.
As illustrated in FIGS. 2 and 3, an outlet chamber
111 is positioned above
the passage
120 in the valve seat
107. The outlet chamber
111
is in communication with a channel
109, an annular gap
121 that surrounds
the pull rod
104 and the portion
114 of working chamber
116
under the piston
105. The inlet chamber
110 is interconnected to
the outlet chamber
111 via passage
120. Thus, the inlet chamber
110
and the outlet chamber
111 of the body
101 are interconnected to
the working chamber
116 and the open section
115 of the body
101
by the gap
121, the channel
109 and the spacing between the piston
105 and the side walls of chamber
116. The outlet chamber
111
is also in communication with the valve outlet
108.
In use, with reference to FIG. 1, the feed line
20 from a delivery truck
16 is connected to the inlet
106 of the quick closing valve. A pressurized
fluid, such as liquid nitrogen, flows from the delivery truck
16 into the
quick closing valve
10 via the feed line
20. As shown in FIG. 2,
when the valve is in the open configuration, the pressurized fluid is able to flow
in the inlet
106, through the inlet chamber
110, through the passage
120 to the outlet chamber
111 and finally out the outlet
108
to the storage tank
22.
As illustrated in FIG. 2, when the fill process begins, the closing element
103
is positioned below the inlet
106 so that the closing element
103
does not interfere with the flow of the liquid through the valve. As liquid flows
through the valve, liquid enters the working chamber
116 through annular
gap
121 and channel
9. The play between the piston
105 and
the walls of chamber
116 permits liquid, or gas evaporated from the liquid,
entering working chamber
116 through annular gap
121 and port
109
to flow around piston
105 and into open section
115. As a result,
the pressure under the piston
105 and the pressure above the piston
105
become equalized.
The safety valve
102 that is fitted on the open section
115 is
set at a predetermined maximum permissible pressure for the inlet of the storage
tank
22 (FIG. 1). As the pressure within the vessel being filled (
22
in FIG. 1) increases, the pressure within working chamber
116 and open section
115 increases. If the pressure within the vessel being filled increases
to the point that the predetermined maximum pressure value of safety valve
102
is exceeded in open section
115, the safety valve
102 opens so that
the pressure above the piston
105 decreases. The resulting difference in
the pressure below the piston
105 and the pressure above the piston
105
initiates upward movement of the piston
105. As such, when the pressure
within open section
115 is relieved due to the opening of safety valve
120,
the piston
105 is raised.
As the piston
105 is raised upward through the working chamber
116
and into the open section
115, the pull rod
104 and the closing element
103 are also raised. As illustrated in FIG. 3, the piston
105 and
the pull rod
104 lift the closing element
103 until it contacts the
valve seat
107 and closes the passage
120 therein. Once the closing
element
103 contacts the valve seat
107, the flow of the fluid into
the storage tank (
22 in FIG. 1) is shut-off.
Consequently, the pressure under the closing element
103 increases
to the value of the pressure of the source while the pressure above the closing
element
103 is kept at the level of the pressure setting of the safety valve
102. This pressure differential maintains the closing element
103
and the piston
105 in a raised position thereby maintaining the valve in
the closed configuration illustrated in FIG. 3. When the piston
105 enters
the open section
115, the area through which the liquid flows around piston
105 increases thereby increasing the flow rate of the liquid from the outlet
108, and consequently from the storage tank
22 through gap
121
and channel
109, working chamber
116, open section
115 and
safety valve
102. This increased flow rate keeps the safety valve
102
in a stable open position until the pressure inside the storage tank
22
decreases to a pressure lower than the predetermined maximum pressure value set
on the safety valve
102.
The quick closing shut-off valve remains closed as long as the pressure at the
valve inlet
106 and in the inlet chamber
110 under the closing element
103 is higher than the pressure in outlet chamber
111 above it or
at the predetermined maximum pressure value set on the safety valve
102.
If the pressure at the inlet
106 decreases below the predetermined maximum
pressure value of safety valve
102, the closing element
103, together
with the pull rod
104 and piston
105, begin to fall downwards within
the body
101. This permits the flow of liquid through valve
10 to
resume. Thus, after the risk of excessive pressure within vessel
22 (FIG.
1) is removed, the quick closing shut-off valve
10 will automatically re-open
and the filling process may continue.
The quick closing shut-off valve of the present invention thus provides simplicity
of design in that the device features essentially one moving element composed of
the closing element
103, pull rod
104 and piston
105. In addition,
the actuating element is a standard safety valve or rupture disk. Such simplicity
of design results not only in low investment cost, but also high reliability of
operation as well.
While various embodiments of the present invention have been described, it
should be understood that other modifications, substitutions and alternatives can
be made without departing from the spirit and scope of the invention, which should
be determined from the appended claims.
*
