Abstract: Apparatus, systems, and methods related to a constant-flow control valve and BTU meter assembly that has a pressure independent, constant-flow control valve assembly connectable to the fluid-based heating or cooling system. A valve stem is connected to a valve member and is rotatable as a unit relative to a valve body to change the position of valve member to change a fluid flow rate through the valve. The valve member's position relative to the fluid path is directly related to the fluid flow rate. Pressure sensors measure the pressure of fluid entering and exiting the valve body. A BTU meter assembly is connected to the valve stem, which is rotatable relative to the BTU meter assembly. A position sensor of the BTU meter assembly detects a rotational position of the valve stem relative to the BTU body.

Abstract: Apparatus, systems, and methods related to a constant-flow control valve and BTU meter assembly that has a pressure independent, constant-flow control valve assembly connectable to the fluid-based heating or cooling system. A valve stem is connected to a valve member and is rotatable as a unit relative to a valve body to change the position of valve member to change a fluid flow rate through the valve. The valve member's position relative to the fluid path is directly related to the fluid flow rate. Pressure sensors measure the pressure of fluid entering and exiting the valve body. A BTU meter assembly is connected to the valve stem, which is rotatable relative to the BTU meter assembly. A position sensor of the BTU meter assembly detects a rotational position of the valve stem relative to the BTU body.

Abstract: A constant-flow control valve and BTU meter assembly that has a pressure independent, constant-flow control valve assembly connectable to the fluid-based heating or cooling system. A valve stem is connected to a valve member and is rotatable as a unit relative to a valve body to change the position of valve member to change a fluid flow rate through the valve. The valve member's position relative to the fluid path is directly related to the fluid flow rate. A BTU meter assembly is connected to the valve stem, which is rotatable relative to the BTU meter assembly. A position sensor of the BTU meter assembly detects a rotational position of the valve stem relative to the BTU body. A controller of the BTU meter assembly determines the fluid flow rate based upon the pressure drop across the valve assembly and the rotational position of the valve stem.

Abstract: A constant-flow control valve and BTU meter assembly that has a pressure independent, constant-flow control valve assembly connectable to the fluid-based heating or cooling system. A valve stem is connected to a valve member and is rotatable as a unit relative to a valve body to change the position of valve member to change a fluid flow rate through the valve. The valve member's position relative to the fluid path is directly related to the fluid flow rate. A BTU meter assembly is connected to the valve stem, which is rotatable relative to the BTU meter assembly. A position sensor of the BTU meter assembly detects a rotational position of the valve stem relative to the BTU body. A controller of the BTU meter assembly determines the fluid flow rate based upon the pressure drop across the valve assembly and the rotational position of the valve stem.

Abstract: In one embodiment, a flow control valve includes a valve body having an inlet, an outlet, a flow passageway coupling the inlet to the outlet, and a cavity with first and second chambers. The valve further includes a hollow piston disposed in the first chamber and a seal separating the first and second chambers. The seal has a section within the piston that is exposed to the fluid in the first chamber. The section of the seal defines a first effective area. The valve also includes a biasing member configured to urge the piston, and a reference pressure passageway in fluid communication with the inlet and the second chamber. The valve can further include a piston seat that has a second inner effective area at least approximately equal to the first inner effective area.

Abstract: In one embodiment, a flow control valve includes a valve body having an inlet, an outlet, a flow passageway coupling the inlet to the outlet, and a cavity with first and second chambers. The valve further includes a hollow piston disposed in the first chamber and a seal separating the first and second chambers. The seal has a section within the piston that is exposed to the fluid in the first chamber. The section of the seal defines a first effective area. The valve also includes a biasing member configured to urge the piston, and a reference pressure passageway in fluid communication with the inlet and the second chamber. The valve can further include a piston seat that has a second inner effective area at least approximately equal to the first inner effective area.

Abstract: In one embodiment, a flow control valve includes a valve body having an inlet, an outlet, a flow passageway coupling the inlet to the outlet, and a cavity with first and second chambers. The valve further includes a hollow piston disposed in the first chamber and a seal separating the first and second chambers. The seal has a section within the piston that is exposed to the fluid in the first chamber. The section of the seal defines a first effective area. The valve also includes a biasing member configured to urge the piston, and a reference pressure passageway in fluid communication with the inlet and the second chamber. The valve can further include a piston seat that has a second inner effective area at least approximately equal to the first inner effective area.

Abstract: In one embodiment, a flow control valve includes a valve body having an inlet, an outlet, a flow passageway coupling the inlet to the outlet, and a cavity with first and second chambers. The valve further includes a hollow piston disposed in the first chamber and a seal separating the first and second chambers. The seal has a section within the piston that is exposed to the fluid in the first chamber. The section of the seal defines a first effective area. The valve also includes a biasing member configured to urge the piston, and a reference pressure passageway in fluid communication with the inlet and the second chamber. The valve can further include a piston seat that has a second inner effective area at least approximately equal to the first inner effective area.