| 摘要 |
In conventional spraying apparatus, material disposed within a material container is kept by means of propellants at an increased pressure with respect to the ambient pressure. The material to be sprayed is dispensed with the aid of a dispensing valve to be operated in a manual way. To avoid the use of propellants which are harmful to the environment, the present invention suggests a spraying apparatus comprising a supply chamber which contains the material to be sprayed and includes a pressure chamber of variable volume. This pressure chamber of variable volume is connected to an actuating means which is provided for increasing the volume of the pressure chamber and thus for sucking material from the supply chamber into the pressure chamber. Since the material within the pressure chamber is kept under pressure by a pressurizing means, a nonreturn valve is disposed in the suction conduit leading to the supply chamber. Material can be sprayed with the aid of said spraying apparatus without any harmful effects on the environment, the use of conventional spraying heads being here possible.
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