Over the years, there has been debate on how best to resolve the balancing issues in many systems. Some of the most common suggestions put forward include undertaking proper designing of systems, choosing the right pumping systems, and having the right control valves in the system. Proper control valves play a critical role in ensuring the balance in a system for optimal performance.
Although there are many ways to control flow in a system, here we will focus on the two major ways -- manual valve operation and automatic valve operation -- and why one is better than the other.
Differences in their working mechanisms
Manual flow control valves
Manual flow control valve operation utilizes throttling valves and allows for the flow in a system to be measured at each branch. With manual flow control valves, a balance contractor must measure the flow and adjust valve openings to achieve the desired flow rates. Manual operation can keep the system balanced in full-load conditions, but as soon as the system dynamics shift slightly, the system goes off balance throughout the operation.
Automatic flow control valves
Automatic flow control valves are designed to maintain the flow rate in the required psid range, even as pressure in the system varies. They provide the system with stability as they react to maintain overall balance when some branches adjust. Automatic flow control valves work as the pressure differential regulator by absorbing any extra pressure changes within themselves, thus ensuring a constant flow rate operation.
Key benefits of automatic control valves over manual control valves
1. Better balance control
Automatic flow control valves work well in maintaining and ensuring a constant flow in a system despite any pressure variations. This ensures there are no balancing issues in the system, unlike with manual flow control valves, where any change in pressure disrupts the balance in the system. With manual control valves, the system needs to be monitored and adjusted to recover its balance when there is a disruption.
2. More cost effective
Automatic flow control valves may be more expensive than manual valves, but you need fewer of them. Automatic valves will save on installation costs because only a few of them are required to be installed at the terminals. Manual flow control valves, on the other hand, need to be installed at all distribution lines, risers, and branches.
3. Easy to install and access
Automatic flow control valves are relatively easy to install and can be accessed easily for maintenance. Plus, their flow cartridge can be changed within the same valve instead of having to replace the whole valve body.
4. Not labor intensive
Once installed, automatic flow control valves do not require any balancing or repetitive maintenance for monitoring as manual control valves do.
5. Offer better stability
The wrong valve sizing can lead to major balancing issues throughout a system. But with automatic valves, the valves are sized by the design flow rate and tend to offer better stability to the system.
In general, automatic flow control valves offer better system control and balancing than manual control valves. They ensure the system runs proficiently at all load conditions, and this ultimately makes them perform better.