The BF-32 series from Kao Lu Enterprise offers a comprehensive range of 3/2-way direct-operated solenoid valves spanning five port sizes from 1/4" to 1". Each size is available in normally closed (NC), normally open (NO), and vacuum (VBF) configurations, giving system designers flexibility across machine tool coolant circuits, vacuum handling systems, and general industrial fluid control.

How do I select the right port size and flow rating?

Port size determines orifice diameter and maximum flow. The 1/4" BF-3202 delivers 1,500 L/min through a 6 mm orifice — suitable for small coolant lines and compact vacuum circuits. The 3/8" BF-3203 (12 mm, 2,000 L/min) and 1/2" BF-3204 (20 mm, 4,000 L/min) cover mid-range machine tool cooling. The 3/4" BF-3206 (20 mm, 5,000 L/min) and 1" BF-3210 (25 mm, 8,500 L/min) target high-volume water systems where fast cycling replaces slow ball valve actuation.

What is the difference between standard and vacuum VBF variants?

Standard BF-32 models operate on positive pressure from 2.5 to 8 bar. VBF vacuum variants (VBF-3202-P through VBF-3210-P) are configured for negative-pressure ON/OFF control rated to 700 mmHg. Note that vacuum models require an external positive pilot pressure supply — they are direct-operated valves, not true pilot-operated designs, and the pilot pressure provides the actuation force needed to shift the spool under vacuum.