Hydrostatic pressure (or often abbreviated as HP) is a non-destructive static testing technique utilized to evaluate the performance of various testing equipment within a variety of industrial applications. It is basically a form of positive displacement testing, wherein one fluid is substituted for another. This technique relies on the theory that a constant volume incompressible fluid is a perfect pressure vessel. The principle is actually very similar to that of a visco-elastic fluid. This means that hydrostatic pressure can be applied to the tested item without the need to add any lubrication or any type of drying mechanism.
The technique has been around for decades and is still a staple testing method today. This means that most of the heavy machinery and industrial equipment that are used in the manufacturing, construction, oil explorations, and mining sectors are using hydrostatic pressure testing machines. Some of these include the following: concrete mixers, centrifuges, drilling rigs, pipe and tubing equipment, water pumps, pump jacks, and outboard motors. Basically, any piece of testing equipment which requires the application of a pressurized liquid is expected to exhibit this type of pressure uniformity when being inspected by a qualified technician.
One of the most common types of hydrostatic pressure testing machines is the closed loop system. In this system, a small and lightweight pump is placed inside an enclosure, while the machine is left running. The machine’s impeller is then placed inside the confined space. As water flows through the pipes contained within the machine, it displaces the fluid being handled inside the pipes. If the flow rate is not controlled, the pressure also increases continuously. To prevent any damage to the inside of the testing machine, manual pressure adjustments are performed periodically.
The other most common Hydrostatic Pressure Testing Machines in the market includes the screw seal assy and the screw top assy. The screw top also uses the principle of counterbalance that forces the liquid against the pipes. Meanwhile, the screw seal assy uses a screw that is inserted into the pipe. After that, a series of plastic pipes are screwed onto the metal pipes. These plastic pipes are then connected to the metal pipes that run into the hydrostatic pressure testing equipments.
For proper investigation of underground pipes, two types of noninvasive testing machines are commonly used. These types are the penetrant injection system and the gravity flow system. With the help of these two testing machines, engineers will be able to determine whether there is any leak inside a hydro-static storage tank.
The penetrant injection system involves a penetrant that is injected in one end of the pipe that runs into the storage tank. After injecting the penetrant, a series of high frequency vibrations will occur within the underground pipe. If the vibration occurs, it means that there is a leak somewhere in the pipe. However, this type of testing equipment cannot determine whether or not there is a leak in the base of the pipe, or in the supporting rod.