Water network management
What is the difference between a water network controlled by upstream and a water network controlled by downstream!
Should a water network be controlled by upstream or downstream? What is a water network controlled by upstream? What is a water network controlled by downstream?
A water network controlled by downstream is a network where the flow inside pipes are dictated by the water users. That is, if we have ten users who use water, we will have a flow rate of 100 (L / min) for example. That is, if we have ten users who use water, we will have a flow rate of 100 (L / min) for example. So, if we have ten water users, we will have a flow of 100 (L / min) for example, if the number of water users increases flow increases accordingly and if the number of users decreases the flow will decrease spontaneously. This is what we called flexibility: responding to a variable flow with an acceptable pressure that is neither too low nor too high. It is horizontal management, water is a shared benefit.
However, a network which is controlled by the upstream is a network where the flow inside pipes are imposed by the upstream decision-makers. You are given the flow that can be given and not the requested rate. A mindset of a security man and not an engineer, this is the case in many countries in developing countries, water is dominated by the powerful and not by the smart. As a result, if the given flow is greater than the requested flow, pressure increase which can damage pipes and equipments, water losses can thus occur, overconsumption, negligence, etc …
However, if the given flow is lower than the requested flow, we will have user dissatisfaction, water cuts, intermittent water supply, social disturbance ... etc . It is a vertical management, water is considered a public good, water belongs to the state. The network operator who decides. Sometimes, they give you water when you don't need and they deprive you of water when you need, Hazrd's law.
Here is an example of a network controlled by upstream in a beverage factory in northern Tunisia.
Figure 1: A water distribution network controlled by upstream
Both pumps are controlled by an on / off electrical cabinet.
- If pump 1 is running: the system provides a flow between 18 and 48 m3 / h
- If pump 2 is running: the system provides a flow between 6 and 42 m3 / h
- If both pumps are in operation: the system provides a flow between 6 and 90 m3 / h
If the requested flow is greater than the delivered flow, there will be a lack of water downstream. If the requested flow is lower than the delivered flow, there will be a high pressure on the network which will induce water losses, degradation of pipes and equipment. How can we transform this network into a downstream-controlled network? The answer is in the following figure 2.
Figure 2: The same downstream control system
The two pressure switches, the pressure tank and the electrical cabinet will allow the system to respond to a variable flow rate required by the downstream with a pressure under control.
Is there any other type of downstream flow control system?
Figure 3: water distribution network supplied by a tower tank.
A technology invented since antiquity and which remains dominant until today. The tower tank responds to a downstream flow that varies from zero to infinity with manageable pressure. Uniform water supply, low operating cost and easy maintenance. Our inks were smarter than we think.