Abstract: Systems for use with liquid chromatography for provision of continuous flow or gradient flow in connection with two pumps providing mobile phase to a valve.

Abstract: Systems for use with liquid chromatography for provision of continuous flow or gradient flow in connection with two pumps providing mobile phase to a valve.

Abstract: A valve is provided for use with liquid chromatography where liquid is provided to the chromatographic analysis equipment at more than one pressure, including up to ultra-high pressures. High and higher pressure operation are provided by application of force by an internal spring while avoiding wear of components by permitting higher pressure operation by mechanical engagement of an internal element to cause the internal spring to increase the force applied to the rotor, without the addition of external additional loading in the high pressure operation.

Abstract: Systems for use with liquid chromatography for provision of continuous flow or gradient flow in connection with two pumps providing mobile phase to a valve.

Abstract: A valve is provided for use with liquid chromatography where liquid is provided to the chromatographic analysis equipment at more than one pressure, including up to ultra-high pressures. High and higher pressure operation are provided by application of force by an internal spring while avoiding wear of components by permitting higher pressure operation by mechanical engagement of an internal element to cause the internal spring to increase the force applied to the rotor, without the addition of external additional loading in the high pressure operation.

Abstract: Systems for use with liquid chromatography for provision of continuous flow or gradient flow in connection with two pumps providing mobile phase to a valve.

Abstract: A combined pump-injector valve system utilizing a monolithic body to provide the barrel of the pump and as the stator of the valve, thus eliminating any need for connections between a pump and a valve, and therefore the potential for high-pressure leaks or pressure reductions. The combined pump-injector valve permits injection of nanoliter-sized samples into a chromatographic column, which is sealed during loading of the sample and filling of the pump, such that complete analyses can be completed with microliters of mobile phase with nanoliters of a sample. The pump-injector valve system further includes a pressure sensor external the barrel of the pump and may include an interim position intermediate loading and injection where the contents of the barrel may be pressurized to a desired pressure.

Abstract: A combined pump-injector valve system utilizing a monolithic body to provide the barrel of the pump and as the stator of the valve, thus eliminating any need for connections between a pump and a valve, and therefore the potential for high-pressure leaks or pressure reductions. The combined pump-injector valve permits injection of nanoliter-sized samples into a chromatographic column, which is sealed during loading of the sample and filling of the pump, such that complete analyses can be completed with microliters of mobile phase with nanoliters of a sample. The pump-injector valve system further includes a pressure sensor external the barrel of the pump and may include an interim position intermediate loading and injection where the contents of the barrel may be pressurized to a desired pressure.

Abstract: A combined pump-injector valve utilizing a single piece as the barrel of the pump and as the stator of the valve, thus eliminating any need for connections between a pump and a valve, and therefore the potential for high-pressure leaks or pressure reductions. The combined pump-injector valve permits injection of nanoliter-sized samples into a chromatographic column, which is sealed during loading of the sample and filling of the pump, such that complete analyses can be completed with microliters of mobile phase with nanoliters of a sample.

Abstract: A combined dual pump-injector valve utilizing a single piece of material to house the barrel for each of the two piston-based pumps and to provide the stator of the associated valve, thus eliminating any need for connections between the pumps and the valve, and therefore eliminating the potential for high-pressure leaks or pressure reductions. The combined dual pump-injector valve permits injection of nanoliter-sized samples into a chromatographic column such that complete analyses can be completed with microliters of mobile phase with nanoliters of a sample.

Abstract: A combined dual pump-injector valve utilizing a single piece of material to house the barrel for each of the two piston-based pumps and to provide the stator of the associated valve, thus eliminating any need for connections between the pumps and the valve, and therefore eliminating the potential for high-pressure leaks or pressure reductions. The combined dual pump-injector valve permits injection of nanoliter-sized samples into a chromatographic column such that complete analyses can be completed with microliters of mobile phase with nanoliters of a sample.

Abstract: A combined pump-injector valve utilizing a single piece as the barrel of the pump and as the stator of the valve, thus eliminating any need for connections between a pump and a valve, and therefore the potential for high-pressure leaks or pressure reductions. The combined pump-injector valve permits injection of nanoliter-sized samples into a chromatographic column, which is sealed during loading of the sample and filling of the pump, such that complete analyses can be completed with microliters of mobile phase with nanoliters of a sample.

Abstract: A variable load mechanism for use in a valve seals the flow of a switched fluid. The flow passes through the mechanism in a region which includes shear seal surfaces. The lives of the components of the valve are extended by limiting the range of excursion in response to valve seat forces. The valve element is provided with a first force from a stack of Bellville washers, for example. A second force acts on the valve element through the spring and is determined by fluid pressure.