The DG type pump is multistage segmented type, the suction port is located on the water inlet section, and the outlet is located on the water outlet section, both vertically upwards.The head can be changed by increasing or decreasing the number of pump stages according use’s requirement.

The main parts of the DG pump are: shaft, bushing, inlet section, middle section, guide vane, outlet section vane, outlet section, impeller, seal ring, balance ring, balance disc, end cover, etc. Its structure and working principle are as follows:

1) The inlet section, the guide vane, the middle section, the guide vane of outlet section, the outlet section and the end cover  form a working chamber of the pump together.

2) Impeller: made of cast iron with blades inside. The liquid enters on one side in the axial direction,Due to unequal pressure on the front and back of the impeller,there is an axial force. It is borne by the balance disc. The static balance test was performed during the manufacture of the impeller.

3) Shaft: Made of high-quality steel with an impeller in the middle, fixed to the shaft with keys, shaft sleeve and sleeve nuts.One end of the shaft is fitted with a coupling part that is directly coupled to the motor.

4)  Sealing ring: made of cast iron.To prevent high pressure water from flowing back to the low pressure part of the pump. They are fixed on the inflow section and the middle section respectively, and can be replaced with spare parts after wear.

5) Balance ring, balance sleeve: made of cast iron and fixed on the water outlet section.They form a balancing device together with the balance disc (except for the 50DG50 type, the balance ring and balance sleeve of the other DG pumps are integrated into the balance disc base).

6)  Balance disc: It is made of wear-resistant cast iron and is mounted on the shaft. It is located between the water outlet section and the tail cover to balance the axial force.

7) Shaft sleeve: It is made of wear-resistant cast iron. It is located in the two packing chambers. It is used to fix the impeller and protect the pump shaft. It is a wearing part and can be replaced by spare parts after wear.

8) Bearing: It is a single row rolling bearing, which is lubricated with calcium-based butter.

9) Packing: It acts as a seal to prevent air from penetrating and a large amount of liquid from leaking out.The packing seal consists of a packing chamber on the inlet and end cover, a packing gland and packing.A small amount of high pressure water flows into the packing chamber to act as water seal. The tightness of the packing must be appropriate, not too tight or too loose, so that the liquid can ooze drop by drop. If The packing is too tight and the shaft will generate heat and consume power. If the packing is too loose and the liquid will lose too much, which reduces the pump efficiency.

The slot line on the shaft of the 65DG50 and 80DG50 outlets is used to indicate the amount of wear on the balance disc.There are two engraved lines on the middle opening surface of the bearing cap, indicating the limit position of the balance disc wear.

The 50DG50 is specifically designed to transport hot water.If the pump is used to pump normal temperature water, the bearing body at both ends should be connected with a 3/8" copper tube or a high-pressure plastic tube, so that the pressure water in the pump can flow through the tube to the packing chamber at both ends to act as water seal.

The outlet flange specification of this series of pumps is 6.4MPa (Pg=64Kgf/cm2--JB879--59). When the number of pumps is small, the gate valve with PN4.0MPa is used.Therefore, it is delivered with an outlet connection. The 65DG50 pump can also be equipped with a Ф80 valve. At this time, the outlet of the pump should be mounted with a pipe reducer.