Structure: Frame plate Pumps bigger than DN80 adopt double casing, foot mounting, changeable and flushable gland. Compressible metal flat gasket is used to seal the clearance between frame plate and cover plate. Flanges Suction is horizontal and discharge is vertical. Flanges are available for bigger orifice load and GB, DIN, ANSI Standard. Suction and discharge flanges can usually bear the same pressure. Hydraulic balance and axial balance Bigger flange orifice ensures low flow rate.  Design of impeller and frame plate ensures low noise. Single suction radially split impeller(type N impeller) has sealed passage. Inducer impeller and open impeller are available for  different specifications. Changeable frame plate and impeller ring protect quick wearing area. Axial force gets balance with front ring or front rear ring with balance holes. Remnant axial force is balanced by thrust bearing. Bearing and lubrication Bearing suspension is an entirety. Bearing adopts oil lubrication. Constant oil cup adjusts oil position automatically. Ring ensures sufficient lubrication when oil position changes so as to avoid partial heating due to  not sufficient lubrication,. According to the working condition, Bearing suspension can be no cooling(with radiator), water cooling(with water cooling sleeve)and wind cooling(with fan). Bearing is sealed by piston anti-dust plate. Shaft sealing Shaft sealing by packing or mechanical seals, maximum shaft run out within 0.05mm. Cover plate available for cooling or heat presentation. Connections with cooling, flushing and sealing liquid. Standardized pipework according to API plans. Assistant interface G or ZG thread on assistant interface (normally designed G thread). Direction of rotation clockwise seen from driven end. Design features-advantages-economic consideration Application ranges For pumping clean, slightly polluted, cold, hot, chemically neutral or aggressive media. 1.In refineries, petrochemical industry, coal processing and low temperature engineering. 2.In chemical industry, paper industry, pulp industry, sugar industry and general processing industries. 3.In water industry, seawater desalination plants. 4.In heating and air-conditioning. 5.Power plants. 6.In environmental protection engineering. 7.In ship and offshore industries. Advantage: 1.Design and maintenance standard complying with process industry is ensured. Rapid disassembly or assembly. Disassembly without removal of pipework and driver. 2.Only 7 bearing frames for 48 sizes. Same hydraulics(impellers) and bearing frames as for light or medium duty series CHZ 3.Low branch velocity, low noise level, due to additional primary measures at impeller, long rated life of casings. 4.Casing joint cannot break. 5.Optimum compliance with various operating conditions, closed  impeller with high efficiency, low NPSHR. 6.When casing and impeller wear rings and shaft seal are subject to wear, casing, impeller and shaft can be reused small wear of casing and impeller wear rings due to absence of solids. 7.Stable, aligning shaft position, robust shaft with small shaft deflection, few components ，few bearing checks required ，no cooling water pipework. No cooling water consumption ,no increased bearing heating, 8.Wear-resistant bearing sealing 9.Possibility of replacing packings or mechanical seals of any design. Economic consideration 1.High reliability and interchangeability .Short shut-down. Low maintenance cost 2.Few components, economic spare .part stock keeping, low stock keeping costs. 3.Long rated life of antifriction bearings, long rated life of shaft seals, short time for shutting- down, low maintenance costs higher efficiency, low operating 4.costs, low costs for pipework support and sound protection, low spare part and repair costs, high reliability. High reliability of pumps, low maintenance periods, low energy costs due to careful pump selection. 5.Small investment costs for plants .Considerable saving of repair and spare 6.part stock keeping costs, short repair periods .Long rated life of packing or mechanicals seals .Short shut downs .Easy maintenance, low operating costs No investment costs for cooling system . 7.High interchangeability, low modification costs .(no machining of stuffing box housing).