Iwaki SMX Series Self-Priming Magnetic Drive Chemical Pumps

Iwaki SMX is a horizontal self-priming magnetic drive pump made of reinforced plastic (GFRPP), used to transfer chemicals where the suction line cannot be kept flooded. The seal-less design has no shaft seal, and the pump needs no external self-priming chamber or valve. Mikron Proses provides selection, quotation and application consulting for Iwaki pumps, including the SMX series.

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For a fluororesin (CFRETFE) version, see the Iwaki SMX-F series; for a non-self-priming GFRPP pump, see the Iwaki MX series. Other Iwaki magnetic-drive pumps are listed under Iwaki magnetic-drive process pumps.

The patented self-radiation structure disperses bearing friction heat to protect the pump under abnormal operating conditions, and the non-contact structure prevents contact between the rear thrust face and the bearing, which eliminates heat buildup during dry running. The wet end can be removed from the motor as a complete assembly by removing the 4 mounting bolts on the motor bracket; a rear casing support makes maintenance and the draining of residual liquid easier.

Self-priming principle and models

When the pump is primed with liquid and started, it sucks gas and liquid into its inlet. The mixture is agitated by the impeller in the front casing and discharged to the rear case, where gas and liquid separate: gas is bled from the discharge port while some liquid is retained, and the liquid in the rear case is fed back to the front casing through a circulation hole. This repeats until the gas on the suction side is completely expelled, after which normal centrifugal pump operation resumes.

The SMX is made in three casing sizes: SMX-22 (25 x 25 mm), SMX-44 (40 x 40 mm) and SMX-54 (50 x 40 mm). The bearing, spindle and liner ring material code has three options: CA (carbon bearing, high purity alumina ceramic spindle), RA (PTFE bearing with filler, high purity alumina ceramic spindle) and KA (SiC bearing, SiC spindle).

Model	Connection	Motor	Max. capacity	Standard duty point (impeller T unless noted)
SMX-220	25 x 25 mm	0.37 kW	90 L/min	80 L/min at 8.5 m (impeller V)
SMX-221	25 x 25 mm	0.75 kW	140 L/min	100 L/min at 13.0 m
SMX-222	25 x 25 mm	1.5 kW	160 L/min	100 L/min at 13.0 m
SMX-441	40 x 40 mm	0.75 kW	115 L/min	100 L/min at 14.0 m
SMX-442	40 x 40 mm	1.5 kW	280 L/min	150 L/min at 12.4 m
SMX-542	50 x 40 mm	1.5 kW	210 L/min	100 L/min at 20.5 m (impeller V)
SMX-543	50 x 40 mm	2.2 kW	440 L/min	250 L/min at 18.0 m
SMX-545	50 x 40 mm	4.0 kW	440 L/min	250 L/min at 18.0 m

Minimum flow, because the pump must not run continuously against a closed discharge: 10 L/min for SMX-22 and SMX-44, and 20 L/min for SMX-54. The suction pipe must have the same diameter as the pump inlet port and must be shorter than 4.7 m; otherwise the self-priming performance can be affected, or priming can even be prevented. Always prime the pump before the first operation, and keep a 10% allowance on the motor output (shaft power x specific gravity x 1.1).

Applications

The SMX is used to pump liquid up from underground tanks or pits (chemical plant, waste plant), to pump up and out from the top of a tank or tanker truck (for example etching and plating chemical from a chemical bath), and to transfer chemical from tank to tank, such as from a main tank to a daily tank or from a drum to a tank. It can be compared with the SMX-F series, which covers the same capacity range with a CFRETFE casing.