The invention discloses a valve. The valve comprises a valve shell body, an upper valve clack, a lower valve clack, a first elastic part and a second elastic part, wherein the valve shell body is internally provided with a hole passage, the upper valve clack comprises a downward spherical surface, the lower valve clack comprises a spherical groove adapted to the spherical surface, the spherical surface directly faces the spherical groove, the first elastic part is connected between the upper valve clack and the hole passage in a sealed manner, and the second elastic part is connected between the lower valve clack and the hole passage in a sealed manner. The valve can be controlled according to the flow quantity.