BACKFLOW PREVENTION DEVICE

• Main Author: OKANO YU
• Format: Patent
• Language: English; Japanese
• Published: 17.12.2020
• Subjects: BLASTING; FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEATGENERATING MEANS, IN GENERAL; HEATING; LIGHTING; MECHANICAL ENGINEERING; RANGES; VENTILATING; WEAPONS

To provide a backflow prevention device capable of sufficiently transmitting a supply pressure of hot water in an upstream passage to an atmosphere open valve, while suppressing intrusion of a foreign object to a pressure detection passage.SOLUTION: A supply passage for supplying hot water to a bathtub can be opened/closed by an opening/closing valve, an atmosphere open valve is connected to a downstream passage further on the downstream side than the opening/closing valve, and an upstream passage 4 further on the upstream side than the opening/closing valve and the atmosphere open valve are communicated with each other by a pressure detection passage 7. The atmosphere open valve receives a supply pressure of the hot water in the upstream passage 4 via the pressure detection passage 7, and when the pressure is equal to or greater than a predetermined pressure, it closes the valve, and when the supply pressure of the hot water lowers in the upstream passage 4, it opens the valve to discharge the hot water in the downstream passage. Also, a cylinder member 42 is inserted inside the upstream passage 4, and an inflow region 40a having a gap A where the hot water can flow in from an upstream end side of the cylinder member 42 is provided between an internal wall surface of the upstream passage 4 and the cylinder member 42. Then, the pressure detection passage 7 is connected in such a manner that an inlet 7a on the upstream passage 4 side opens to the internal wall surface of the upstream passage 4 in a state of being surrounded by the gap A of the inflow region 40a.SELECTED DRAWING: Figure 5 【課題】検圧通路への異物の侵入を抑制しながら、上流通路の湯水の供給圧力を大気開放弁に十分に伝えることが可能な逆流防止装置を提供する。【解決手段】浴槽に湯水を供給するための供給通路を開閉弁で開閉可能であり、開閉弁よりも下流側の下流通路に大気開放弁を接続すると共に、開閉弁よりも上流側の上流通路４と大気開放弁とを検圧通路７で連通させる。大気開放弁は、検圧通路７を介して上流通路４における湯水の供給圧力を受けて所定圧力以上であれば閉弁し、上流通路４で湯水の供給圧力が低下すると開弁して下流通路の湯水を排出する。また、上流通路４の内側に筒部材４２を挿入し、上流通路４の内壁面と筒部材４２との間に、筒部材４２の上流端側から湯水が流入可能な隙間Ａを有する流入領域４０ａを設ける。そして、検圧通路７を、上流通路４側の入口７ａが流入領域４０ａの隙間Ａに囲まれた状態で上流通路４の内壁面に開口するように接続しておく。【選択図】図５