Basic (N)
The pump and motor are connected by an adapter plate or a FB housing. A portion of the liquid being pumped is taken from the impeller outlet part of the pump chamber into the rotor chamber for the purposes of cooling the motor and lubricating the bearings. Then, the fluid is returned to the pump chamber through the hollow shaft. A cooling jacket may be fitted to the outer wall of the stator assembly depending on the temperature and other characteristics of the liquid being pumped.

Circulation Boost Basic (V)
The cross-sectional dimensions are the same as those of the basic design (N type), but the return passage is wider to maintain a return flow of liquid when handling high-viscosity (80 to 200 mPas) liquids.

Design for high temperatures (T)
Pump and motor are connected with an adapter. The adapter separates the pump thermally from the motor and prevents heat transfer from the pump to the motor. In the design for high temperatures, an independent circulating system is provided for cooling the motor and lubricating the bearings. Circulation is effected by the auxiliary impeller located at the front end of the rotor chamber. A heat exchanger is fitted to the outer wall of the stator assembly to cool the circulation liquid.

Design for high temperatures, without cooling (HX)
The HX type is intended for pumping liquids with high temperatures. Cooling is not required when using a special ceramic motor insulation. The HX type can be installed with a heating jacket and is well suited for handling high melting point liquids (above 140 °C) which exceed the temperature limit of normal organic motor insulation materials.

Slurry handling (S)

The basic construction is identical to that of the pump version for high temperatures. The function of this arrangement is to prevent the slurry handled from entering into the rotor chamber. Clean liquid compatible with the liquid that is pumped is flushed from the inlet port on the rear of the motor to prevent slurry from entering into the rotor chamber. Normally, a backflushing line would be required for this. See Fig. 4-2 for the amount of liquid used for back flushing.

Mechanical seal when handling slurry (M)
A design is also available with a mechanical seal between the pump and motor due to the requirement of decreasing the amount of liquid used for backflushing. (See Fig. 1-5). This pump type is called a slurry handling pump with a mechanical seal (M type). The backflushing volume can be decreased up to 100 ml/day to 500 ml/day. (See Fig. 4-2).

Slurry handling, gas seal (LG)
A gas seal type is also available which is suitable for handling heavily corrosive liquid, liquid liable to polymerize or liquid with a high concentration of slurry (see Fig. 1-6). The construction is nearly identical to that of the slurry handling pump with mechanical seal listed above. The special feature of this pump type is that a gas chamber is located between the pump unit and the motor unit. The gas chamber separates the pump unit from the motor unit completely. This prevents the risk that the mechanical seal wears out or corrodes through the pumped liquid. Like the backflushing liquid (100 ml/day to 500 ml/day), clean original liquid or clean liquid can be mixed with the pumped liquid if only a very small amount is used. Also, because gas collects in the gas seal chamber, for example, air can be used on nitrogen (see Fig. 4-3).

Slurry handling, gas seal (G)
Vertical line pump with mechanical seal. A gas chamber between the pump body and motor prevents damage to the mechanical seal through slurry.

Design for high melting point (B & C)
This pump has a construction suitable for liquids with a high solidifying point. It is provided with a heating jacket on the outer face of the pump and the motor to prevent liquid from solidifying at a time of the liquid filling and during the pump operation. According to the solidifying point of the fluid and the fluid temperature, a simple design for fluids with high melting point (C type) and a complete version for fluids with high melting point (B type) are available.

Design with reverse circulation (Q)
The notable feature for this pump is that the circulation line does not form a closed circuit. The circulating fluid passes through the front bearing housing from the impeller outlet part of the pump volute chamber into the rotor chamber. From there it passes through the rotor chamber and—after escaping out of the outlet on the rear bearing housing at the rear of the motor—returns to the vapor zone in the suction tank through the reverse circulation line (see Figure 4-4). In the basic design, an evaporative liquid evaporates if the temperature of the circulating fluid increases ever so slightly once the fluid flows through the rotor chamber and causes cavitation, etc.

Self-primping pump, horizontal (DN)
The underlying structure is identical to the basic design. This pump type is designed so that the pump is self-priming even without a flap valve present. Since there is no flap valve, heavily corrosive liquid can also be handled; in addition, there is no possibility of poor self-priming due to a blockage in the flap valve.

Design with low flow & higher head and high speed (HK)
The HK type is designed for handling easily evaporating fluid without additional reverse circulation line piping. This pump can maintain higher pressure than the vapor pressure in the motor chamber, thereby preventing evaporation. If you are interested in the HK pump type, please contact Nikkiso Co., Ltd.

Multistage
Efficient operations in high head applications.