Diaphragm Pump Price? Do you wish to purchase a Cast Iron Diaphragm Pump of the highest calibre? Based on their mode of operation, diaphragm pumps have the following qualities that you should check for before purchasing one. Consider what follows: Flowing liquid pulses Due to the intermittent flow of liquid caused by the alternating of suction and discharge. Air Operated Double Diaphragm pumpPulsation separates Stainless Steel Diaphragm Pumps from Cast Iron Diaphragm Pump. Later, we'll go into greater detail about this.