A steam valve has a tubular stop valve configured to move toward an upper end side and a lower end side along an axial direction when the stop valve is opened and closed respectively; and a valve main body configured to accommodate the stop valve. The stop valve has a ring-shaped protrusion portion protruded outwardly in a radial direction. The valve main body has an accommodation space for accommodating the protrusion portion which is divided by the protrusion portion into a first pressure space and a second pressure space. First and second feed/discharge portions configured for adjusting a pressure in the first pressure space and the second pressure space respectively are further provided. The protrusion portion is moved upwardly and downwardly by adjusting the pressure in the first pressure space and the second pressure space.

A flow control device for controlling flow in a heating, ventilation, or air conditioning (HVAC) system is shown. The flow control device includes a valve body including an inlet path, an outlet path, a valve member, and a valve stem coupled to the valve member. The flow control device includes a first sensor configured to obtain pressure measurements within the valve body, a second sensor configured to obtain displacement measurements of the valve stem, and a controller including a processing circuit configured to determine a flowrate based at least on the pressure measurements from the first sensor and the displacement measurements from the second sensor.

Provided are a control method, a control system and an electric valve. The control method includes steps described below. An actually measured setting parameter curve is acquired. A required setting parameter curve is acquired. Both the actually measured setting parameter curve and the required setting parameter curve represent a corresponding relationship between a position of the electric valve and a setting parameter. The actually measured setting parameter curve and the required setting parameter curve are fitted to acquire a position mapping curve. A setting required position is obtained according to a required setting parameter and the required setting parameter curve, and a setting actual position is acquired according to the setting required position and the position mapping curve. The electric valve is controlled to run toward the setting actual position of the electric valve.

In order to achieve an enlargement of a seating surface, and to additionally achieve an improvement in productivity while forming this seating surface using a resin layer, without having to sacrifice any of the drive range of the valve body, there is provided a fluid control valve that is formed such that drive force from an actuator is transmitted to a valve body via a plunger, and that controls a flow of a fluid by causing a seating surface of the valve body to move towards or away from a valve seat surface of a valve seat, wherein the valve body is a separate body from the plunger, and the seating surface is formed by a resin layer.

Example fluid valves having non-circular flow passageways are disclosed. An example fluid valve includes a body defining a fluid passageway between an inlet and an outlet, at least a portion of the fluid passageway between the inlet and the outlet has a generally non-circular cross-sectional shape when taken along a plane transverse to a direction of fluid flow, the cross-sectional shape includes a curved central axis, with outwardly curved end walls and curved lateral walls joining the curved end walls.

A fluid micro-injection device comprises an execution system (100) and a flow channel assembly (200) connected with the execution system (100). The execution system (100) includes a base body (110), a movable member (120), an executor, an adjusting member (130) and a plurality of clearance sheets. The flow channel assembly (200) have a fluid seat (210), a nozzle (220) and a fluid supply joint (230).

An apparatus, system and method for regulating fluid flow are disclosed. The apparatus includes a flow rate sensor and a valve. The flow rate sensor uses images to estimate flow through a drip chamber and then controls the valve based on the estimated flow rate. The valve comprises a rigid housing disposed around the tube in which fluid flow is being controlled. Increasing the pressure in the housing controls the size of the lumen within the tube by deforming the tube, therefore controlling flow through the tube.

An apparatus, system and method for regulating fluid flow are disclosed. The apparatus includes a flow rate sensor and a valve. The flow rate sensor uses images to estimate flow through a drip chamber and then controls the valve based on the estimated flow rate. The valve comprises a rigid housing disposed around the tube in which fluid flow is being controlled. Increasing the pressure in the housing controls the size of the lumen within the tube by deforming the tube, therefore controlling flow through the tube.