Pressure Tank Evaluations

A constant speed, automated pump station almost invariably utilizes a hydropneumatic pressure tank of one type or another. Hydropneumatic tanks contain both air and water. Under increasing pressure, the air compresses, storing energy, and acting like a big, spring-loaded piston to push water into the irrigation system when the pumps are not running. For stations with a bladder tank, water is contained in an expanding bag, or bladder, and does not come into contact with the walls of the tank as long as the bladder remains intact. The air charge in the tank is captive between the tank wall and the bladder. If the bladder fails, the air charge in the tank is captive between the tank wall and the bladder. If the bladder fails, the air charge is soon lost. The effect is usually quite noticeable, and the tank is soon replaced. The other type of hydropneumatic tank, which is the most common tank on vertical turbine and higher pressure pump systems, is simply a large steel cylinder with end caps called "dished heads". Air is introduced into the tank from either an external air compressor, or perhaps from the initial start-up of the turbine pumps. The water is in direct contact with the steel sides of the tank. Over time, the laws of nature prevail and the steel will corrode. The corrosive chemicals such as chlorine or sulfur, will impact the rate of corrosion.
The danger of a corroded tank under high pressure cannot be overemphasized. Every year, somewhere in the country, an old steel tank ruptures and bursts with catastrophic force. Pump motors are flooded, electrical equipment is ruined, pump house structures are damaged. And sometimes someone is killed.
If you have an old pressure tank which has begun to leak, you should take it out of service immediately and call someone to evaluate it. If you have an aging tank which isn't leaking but you are concerned about, call ProPump and Controls. ProPump & Controls has ultrasonic metal thickness testers which we use spot check for potential problem areas. We cannot certify your tank as 100% safe without performing a visual inspection from inside the tank, which is not possible in the majority of tanks on irrigation pump stations. However, if our testing shows any significant pitting, rust buildup, or reduction in metal from the original thickness, you will know for sure that it is time to remove or replace the tank.
Call your nearest ProPump And Controls office for more details.
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