... , our company has designed this new type bench water circulating vacuum pump, its functions an (1) the machine is installed with ... noise created by liquid and gas contained in water, making vacuum degree higher and more stable.Corrosion resisting ,pollutionfree, low noise ... those SHB-III and SHB-IIIS Type Vacuum Pumps. But its important parts of jetting devices, three-way devices, check valve and ...