Abstract: A valve includes at least one valve stem seal, such as a packing seal, that is included in a removable seal cartridge. The valve stem is connected to the actuator via a linkage, which can be removed to provide a linkage gap between the actuator and the valve stem. The seal cartridge can then be slid along the valve stem into the linkage gap and laterally removed from the valve, whereupon the seals within the seal cartridge can be refurbished. The valve can be a rotary or linear valve. In embodiments, the linkage gap can be increased by linear displacement of the actuator away from the valve stem. The seal cartridge can be re-installed in the valve after refurbishment, or a substantially identical replacement seal cartridge can be provided, and can be installed in the valve in replacement of the removed seal cartridge, thereby minimizing downtime of the valve.

Abstract: A valve system for controlling a corrosive process liquid flow, while avoiding corrosion due to a liquid/vapor interface of the process liquid, causes the process liquid to flow from the valve through a purge port into a vertical segment of a purge line. During valve initialization, a non-reactive gas backpressure within the purge line is controlled to establish the liquid/vapor interface at a desired height within the vertical segment, as determined by an interface level sensor, which can be ultrasonic. The vertical segment is constructed from, or lined with, a material that can withstand contact with the liquid/vapor interface. During valve operation, the non-reactive gas pressure can continue to be regulated, or a purge valve can be shut, trapping a fixed quantity of the non-reactive gas within the purge line. The valve can include a heater configured to prevent a molten process liquid from solidifying within the valve.

Abstract: A valve configured to control a flow of a process fluid includes a pair of packing seals separated by a seal gap space along a linear valve stem of the valve, and a pressurization port that can be used to apply a pressurizing fluid, such as nitrogen gas, to the seal gap at a gap pressure that is higher than the process fluid pressure, thereby ensuring that any leakage past the packing seals will be of pressurizing fluid into the process fluid and/or into the environment, and that no process fluid will escape into the environment. The pressure or flow rate of the pressurizing fluid can be monitored to detect and quantify any pressurization fluid leakage past either of the packing seals, so that a maintenance action can be applied to the valve, such as re-tightening or replacing at least one of the packing seals, or replacing the valve.

Abstract: A valve for controlling a molten liquid includes an expansion port in liquid communication with an internal volume of the valve that is filled with the molten liquid. An expansion valve can be opened during unfreezing of the valve, to allow melting process substance to expand out of the internal volume into an expansion line as it is melted. During initialization of the valve, an inert gas source, pressure regulator, and ultrasonic transition level sensor can be used to establish a liquid/gas interface at a desired height within the expansion line. The valve can include a multi-zone heater, wherein a first of the zones is adjacent the expansion port, so that during unfreezing, after the first zone has been melted, the remaining zones can be sequentially activated in an order that ensures that each zone is activated only after an adjacent zone has been melted.

Abstract: An apparatus for measuring a pressure of a corrosive or high temperature process liquid includes a pressure sensor in communication with the process liquid via a vertical tube. A buffer gas injected into the vertical tube forms a liquid/gas interface at a desired height. The buffer gas supply is then either isolated or regulated so as to cause the buffer gas pressure within the vertical tube to remain equal with the process liquid pressure. The pressure sensor indirectly measures the process liquid pressure by measuring the buffer gas pressure within the vertical tube, while remaining chemically and thermally protected from the process liquid. In embodiments, pressure measurements from a pair of gas buffered pressure sensors located upstream and downstream of a valve are combined with measurements of the process liquid temperature to determine a flow rate of the process liquid through the valve.

Abstract: A valve system for controlling a corrosive process liquid flow, while avoiding corrosion due to a liquid/vapor interface of the process liquid, causes the process liquid to flow from the valve through a purge port into a vertical segment of a purge line. During valve initialization, a non-reactive gas backpressure within the purge line is controlled to establish the liquid/vapor interface at a desired height within the vertical segment, as determined by an interface level sensor, which can be ultrasonic. The vertical segment is constructed from, or lined with, a material that can withstand contact with the liquid/vapor interface. During valve operation, the non-reactive gas pressure can continue to be regulated, or a purge valve can be shut, trapping a fixed quantity of the non-reactive gas within the purge line. The valve can include a heater configured to prevent a molten process liquid from solidifying within the valve.

Abstract: A valve includes at least one valve stem seal, such as a packing seal, that is included in a removable seal cartridge. The valve stem is connected to the actuator via a linkage, which can be removed to provide a linkage gap between the actuator and the valve stem. The seal cartridge can then be slid along the valve stem into the linkage gap and laterally removed from the valve, whereupon the seals within the seal cartridge can be refurbished. The valve can be a rotary or linear valve. In embodiments, the linkage gap can be increased by linear displacement of the actuator away from the valve stem. The seal cartridge can be re-installed in the valve after refurbishment, or a substantially identical replacement seal cartridge can be provided, and can be installed in the valve in replacement of the removed seal cartridge, thereby minimizing downtime of the valve.

Abstract: A valve for controlling a molten liquid includes an expansion port in liquid communication with an internal volume of the valve that is filled with the molten liquid. An expansion valve can be opened during unfreezing of the valve, to allow melting process substance to expand out of the internal volume into an expansion line as it is melted. During initialization of the valve, an inert gas source, pressure regulator, and ultrasonic transition level sensor can be used to establish a liquid/gas interface at a desired height within the expansion line. The valve can include a multi-zone heater, wherein a first of the zones is adjacent the expansion port, so that during unfreezing, after the first zone has been melted, the remaining zones can be sequentially activated in an order that ensures that each zone is activated only after an adjacent zone has been melted.

Abstract: An apparatus for measuring a pressure of a corrosive or high temperature process liquid includes a pressure sensor in communication with the process liquid via a vertical tube. A buffer gas injected into the vertical tube forms a liquid/gas interface at a desired height. The buffer gas supply is then either isolated or regulated so as to cause the buffer gas pressure within the vertical tube to remain equal with the process liquid pressure. The pressure sensor indirectly measures the process liquid pressure by measuring the buffer gas pressure within the vertical tube, while remaining chemically and thermally protected from the process liquid. In embodiments, pressure measurements from a pair of gas buffered pressure sensors located upstream and downstream of a valve are combined with measurements of the process liquid temperature to determine a flow rate of the process liquid through the valve.

Abstract: A valve configured to control a flow of a process fluid includes a pair of packing seals separated by a seal gap space along a linear valve stem of the valve, and a pressurization port that can be used to apply a pressurizing fluid, such as nitrogen gas, to the seal gap at a gap pressure that is higher than the process fluid pressure, thereby ensuring that any leakage past the packing seals will be of pressurizing fluid into the process fluid and/or into the environment, and that no process fluid will escape into the environment. The pressure or flow rate of the pressurizing fluid can be monitored to detect and quantify any pressurization fluid leakage past either of the packing seals, so that a maintenance action can be applied to the valve, such as re-tightening or replacing at least one of the packing seals, or replacing the valve.

Abstract: A bellows seal valve includes a pressurization port that can be used to apply a compensating pressure to the “atmosphere” side of the bellows, i.e. the side of the bellows that is opposite to the process fluid. The atmosphere side can be on the interior or exterior of the bellows. The compensating pressure can be greater than the process fluid pressure, to ensure that any leakage will be of pressurizing fluid into the process fluid or into the environment, and that no process fluid will escape into the environment. The pressure or flow rate of the pressurizing fluid can be monitored to detect bellows and packing leaks. A pressurizing fluid exit port can be provided, so that the pressurizing fluid can be circulated through the valve, thereby moderating the bellows temperature under conditions of extreme process fluid temperature.