The rain alarm valve♦↔  is also called the automatic∑ ∏♥ valve of the deluge v♣<∑alve. It can be supplied to the ​₹open piping system of the rain system or the auto©↓matic water supply control >≥ valve of the closed piping system ofΩ<® the preaction system by means of the operφ•δ↑ation auxiliary mechanism. The™‍ flap can be opened electrical‍₽♥ly, mechanically or other $♥₩wise. So what kind of characteristics does it¥₽∑ have? The function of the €↑pre-action system is that it can balance both dry'  and wet systems. In normγ al pipelines, there is no water. It <↔"is linked with the alarm system. Once the alσ¥arm is issued, the water can be pre-fil'σ₩led. The nozzle is closed. The systeα☆m uses a deluge valve. . This systeδ•₹m has higher requirement≠$ ¥s, and the advantage ♠±is that there is no water in the pi↔♠γpe, which can prevent accidental spray or c>∏ racking. Moreover, the rain system and​σ∑ the pre-action system use different≥​ parts, and the designed flow rate ≠£and the required water amou↔∑≈"nt are different, which is a big d₽→ifference. As for the other differencesδ✘ in working principle, ™φ׶it is not too big.