... Airconditioning-Vessel Standard equipment Qingzhou Yongsheng Dredging Machinery Co., Ltd. was established in 1990. Our company is the ... -digging machinery, sand making machinery, dredging machinery, and mineral processing machinery in Qingzhou. Since 1990, we have taken ... The products of our company are sand-digging machinery, mineral processing machinery, sand washing machines, sand pumping ships, ...