Dry running of pumps implies they being operated without any liquid inside, and this is not recommended at all. This is because of an obvious reason that a lot of heat will be generated, there will be friction between some components, and a possible damage to impellers. There are many damages, which could occur because of dry running. So dry running of pumps should be avoided at all costs. This post discusses various factors that lead to dry running of pumps, and ends by letting you know of an effective way to prevent it.
A Brief Discussion on Dry Running of Pumps and the Damages Caused
Apart from total absence of fluid, dry running also implies insufficient quantity of fluid inside. Most pumps are programmed for a minimum fluid quantity or flow rate depending upon various application parameters. Some pumps are, however, designed to stop running once a dry run is indicated. For instance, in a water distribution system, once the flow of water stops, the pump runs dry for a few seconds before it stops as the brief dry run is an indicator that the flow of water has stopped. However, prolonged dry running can damage the pump. Here are some pointers on how dry running can induce damages:
- Dry running increases the pressure on the pump and a lot of heat is generated.
- It can be extremely expensive for organizations if the dry running causes total pump failure and requires a replacement. This is apart from the halted productivity.
- Mainly, human errors are responsible for dry running of pumps, and one of them is closing the suction valve, which stops the flow.
- Some other wrong practices include dry running a pump to check pump cavitation, and this is definitely not recommended. There are better ways to identify pump cavitation.
- If the pump is huge with many impellers and rotators, and used for transferring viscous or semisolid fluids, the damage due to dry running will be quicker.
- Undue pressure surg. will lead to the damage of impellers.
- The properties of the liquid being transferred also matter. For instance, pumps transferring hot or chemically aggressive fluids are more likely to damage faster than the ones transferring cooler fluids.
- Proper lubrication of the pumping system is key. Some fluids have the properties of lubricating the linings of the pump, which prevents heat generation and wear. However, if that is not the case, then as part of maintenance, lubrication is a crucial activity.
- If the offloading task is over, the tank operator must ensure to switch off to prevent dry running as this is the most common manual errors which lead to dry runs.
- Certain tools such as Techna-Guard monitor the power consumption of the motor and offer valuable inputs on load and performance.
- It protects the pump against dry running, clogging, cavitation, and overload.
- It controls the feed rate and keeps it at an optimum level.
- It evaluates the changes in the fluid viscosity.
- It is easy to install and use.
- It issues alert messages in case of loss of load, shock load, bad bearings, or mechanical failure.
- It monitors the pump and fan flow.
Does your application involve transfer of fluids from one point to another? In this case you may be using a pumping system. If you plan to install a monitoring system to prevent your pump from dry running and other related damages, ensure you source this system from a reputed manufacturer and service provider. Techna-Tool manufactures, installs, and provides services production monitoring systems. Techna-Guard is a tool which monitors load and power consumption, and optimizes machinery and processes driven by 3-phase AC motors.