Method and apparatus for online switching between supply vessels
First Claim
1. An apparatus for continuously supplying a liquid composition to a downstream process, comprising:
- (a) a first vessel containing a first batch of the liquid composition and having a first vessel isolation valve;
(b) a second vessel containing a second batch of the liquid composition and having a second vessel isolation valve;
(c) a vessel selection valve including a first switch valve and a second switch valve;
(d) a first outlet conduit from the first vessel isolation valve to the first switch valve;
(e) a second outlet conduit from the second vessel isolation valve to the second switch valve;
(f) a first conductivity sensor located in the first outlet conduit at a first known distance from the first switch valve for measuring electrical conductivity of the composition in the first outlet conduit;
(g) a second conductivity sensor located in the second outlet conduit at a second known distance from the second switch valve for measuring electrical conductivity of the composition in the second outlet conduit;
(h) a delivery conduit connected to the vessel selection valve for transmitting fluid therethrough downstream of the vessel selection valve;
(i) a process control computer receiving input from the first and second conductivity sensors and controlling actuation of the first and second switch valves in response thereto, the computer opening the second switch valve and closing the first switch valve when the conductivity in the first outlet conduit is outside a predetermined range, the computer delaying closing the first switch valve for a period time to allow for liquid in the first outlet conduit below the first conductivity sensor to reach the first switch valve before closing the first switch valve.
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Accused Products
Abstract
A method and apparatus for switching a supply to a process from a first vessel to a second vessel. Liquid is flowed from the first vessel through a first outlet conduit through a vessel selection valve, including first and second switch valves, to the process. A conductivity sensor measures the conductivity level of the liquid in the first outlet conduit at a point upstream of the selection valve and a computer compares the conductivity level to a predetermined range. The computer signals an isolation valve, in a second outlet conduit from the second vessel, to open and allow liquid to displace air in the second outlet conduit from the second vessel to the selection valve. The computer determines a delay to allow liquid below the first conductivity sensor to reach the first switch valve, then closes the first switch valve and opens the second switch valve.
9 Citations
10 Claims
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1. An apparatus for continuously supplying a liquid composition to a downstream process, comprising:
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(a) a first vessel containing a first batch of the liquid composition and having a first vessel isolation valve;
(b) a second vessel containing a second batch of the liquid composition and having a second vessel isolation valve;
(c) a vessel selection valve including a first switch valve and a second switch valve;
(d) a first outlet conduit from the first vessel isolation valve to the first switch valve;
(e) a second outlet conduit from the second vessel isolation valve to the second switch valve;
(f) a first conductivity sensor located in the first outlet conduit at a first known distance from the first switch valve for measuring electrical conductivity of the composition in the first outlet conduit;
(g) a second conductivity sensor located in the second outlet conduit at a second known distance from the second switch valve for measuring electrical conductivity of the composition in the second outlet conduit;
(h) a delivery conduit connected to the vessel selection valve for transmitting fluid therethrough downstream of the vessel selection valve;
(i) a process control computer receiving input from the first and second conductivity sensors and controlling actuation of the first and second switch valves in response thereto, the computer opening the second switch valve and closing the first switch valve when the conductivity in the first outlet conduit is outside a predetermined range, the computer delaying closing the first switch valve for a period time to allow for liquid in the first outlet conduit below the first conductivity sensor to reach the first switch valve before closing the first switch valve.
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2. An apparatus for switching supply from a first vessel containing a first batch of a liquid composition to a second vessel containing a second batch of the liquid composition, both supplying the liquid composition to a downstream process, comprising:
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(a) a first vessel isolation valve;
(b) a second vessel isolation valve;
(c) a vessel selection valve including a first switch valve and a second switch valve;
(d) a first outlet conduit from the first vessel isolation valve to the first switch valve;
(e) a second outlet conduit from the second vessel isolation valve to the second switch valve;
(f) a first conductivity sensor located in the first outlet conduit at a first known distance from the first switch valve for measuring electrical conductivity of the composition in the first outlet conduit;
(g) a second conductivity sensor located in the second outlet conduit at a second known distance from the second switch valve for measuring electrical conductivity of the composition in the second outlet conduit;
(h) a delivery conduit connected to the vessel selection valve for transmitting fluid therethrough downstream of the vessel selection valve;
(i) a process control computer receiving input from the first and second conductivity sensors and controlling actuation of the first and second switch valves in response thereto, the computer opening the second switch valve and closing the first switch valve when the conductivity of the liquid in the first outlet conduit is outside a predetermined range, the computer determining a period of delay for closing the first switch valve that will allow the liquid in the first outlet conduit below the first conductivity sensor to reach the first switch valve before closing the first switch valve. - View Dependent Claims (3, 4, 5, 6)
(a) a first flush/drain valve associated with the first switch valve;
(b) a second flush/drain valve associated with the second switch valve; and
(c) a flush/drain connected to the vessel selection valve and communicating with both the first flush/drain valve and the second flush/drain valve.
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4. An apparatus as recited in claim 3 the vessel selection valve further comprising:
a flush/purge valve in the delivery conduit upstream of the first and second switch valves allowing reverse flow flushing and purging of the delivery conduit through the vessel selection valve.
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5. An apparatus as recited in claim 3 wherein:
the vessel selection valve is a single multiport valve assembly.
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6. An apparatus as recited in claim 3 wherein:
the vessel selection valve is a combination of interconnected valves and multiport valves.
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7. A method for switching supply from a first vessel containing a first batch of a liquid composition to a second vessel containing a second batch of the liquid composition, both supplying the liquid composition to a downstream process, comprising the steps of:
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(a) flowing the liquid composition from the first vessel through a first outlet conduit from the first vessel and through a vessel selection valve to a downstream process, the vessel selection valve including a first switch valve and a second switch valve;
(b) sensing a conductivity level of the liquid composition at a point in the outlet conduit from the first vessel before the vessel selection valve, the computer means comparing the conductivity level to a predetermined range;
(c) the computer signaling a vessel isolation valve in a second outlet conduit from the second vessel to open, thereby displacing air in the second outlet conduit and filling the second outlet conduit with the liquid composition from the second vessel to the vessel selection valve;
(d) the computer determining a first period of delay for closing the first switch valve that will allow the liquid in the first outlet conduit below the first conductivity sensor to reach the first switch valve before closing the first switch valve;
(e) the computer closing the first switch valve and opening the second switch valve after a first time period that is not greater than the first period of delay; and
(f) flowing the liquid composition from the second vessel through the second outlet conduit and through the vessel selection valve to the downstream process. - View Dependent Claims (8, 9, 10)
the second switch valve opened before the first switch valve is closed.
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9. A method as recited in claim 8 further comprising the steps of:
purging and draining the first outlet conduit through the vessel selection valve after the first switch valve has been closed.
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10. A method as recited in claim 9 further comprising the steps:
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(a) placing a new batch of the liquid composition in the first vessel;
(b) sensing a conductivity level of the liquid composition at a point in the second outlet conduit from the second vessel prior to the vessel selection valve, the computer means comparing the conductivity level to the predetermined range;
(c) the computer signaling a vessel isolation valve in the first outlet conduit to open, thereby displacing air in the first outlet conduit and filling the first outlet conduit with the liquid composition from the first vessel to the vessel selection valve;
(d) the computer determining a second period of delay for closing the first switch valve that will allow the liquid in the second outlet conduit below the second conductivity sensor to reach the second switch valve before closing the second switch valve;
(e) the computer closing the second switch valve and opening the first switch valve after a second time period that is not greater than the second period of delay; and
(f) flowing the liquid composition from the first vessel through the first outlet conduit and through the vessel selection valve to the downstream process.
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Specification