| 摘要 |
<p>The mixer valve of a central heating installation is controlled automatically without the need for an energy source such as electricity. A large surface area unit is placed outside the building and is filled with a high expansion liq. This is conveyed to a cylinder inside the building, changes in temperature causing movement of a sliding piston. This piston is connected to a lever operating a cable attached to the mixer valve control. Liq. expansion provides the force to operate the valve, a counter-weight being used for liq. contraction.</p> |
