| 摘要 |
<p>A flow controller device includes a valve assembly connected with a tensiometer to provide automatic control of flow of water for irrigation, including variable control of the rate of flow according to the matric tension of the soil for water. The tensiometer is made of a porous cup and a connecting tube to measure this tension of the soil, which depends on the moisture and type of the soil. The valve assembly is formed of a piston moving in a cylinder, to move a rod connected to the piston. A cavity on the piston end of the cylinder connects with the tensiometer, and at the far end of the rod a flow valve is formed. As the soil dries, water moves out of the tensiometer's porous cup into the soil, reducing the pressure in the tensiometer and cylinder cavity, thereby shifting the piston to begin or increase the flow for irrigation. As soil moisture increases, water moves back into the tensiometer, increasing its pressure, thereby moving the piston to close the flow valve. A spring can be adjusted to control flow, and a scale and pressure gauge provided for calibrating the unit. The unit is self-contained and easy to manufacture, requires no outside power and can be easily calibrated by a spring adjustment for a desired flow.</p> |
