Closed sand pumping box for pumping sand

The utility model discloses a closed sand pumping box for pumping sand, which comprises a sand pumping box body, a filter device, a reinforcer, a rear cover plate and a sand baffle, the sand pumping box body is provided with a sand discharge port, a sand inlet and a fan connector, the sand inlet is used for being connected with a sand pumping pipe, the fan connector is used for being connected with an air inlet of a sand pumping fan, and the filter device is arranged on the sand pumping box body. The sand pumping fan is used for pumping air from the sand pumping box body, so that negative pressure is formed in the inner cavity of the sand pumping box body, and then the sand pumping pipe is used for pumping sand; the filter device is arranged at the fan connector; the plurality of reinforcing pieces are arranged on the outer side of the side wall of the sand pumping box body; the rear cover plate is arranged at the sand discharging opening and used for opening/closing the sand discharging opening. The sand blo