Why do we need to synchronize? Can one pump handle it?
It might not be possible to do so.
Imagine this: You need to transport the ore slurry from the beneficiation plant at the foot of the mountain to the tailings reservoir at the top of the mountain, with a vertical height difference of several hundred meters. The lift of a single pump might only be 40-50 meters, which is simply not enough to reach. Or, you need to transport several thousand cubic meters of slurry per hour, and a single pump's flow rate limit cannot meet this requirement.
At this point, multiple pumps need to "work together hand in hand". According to the requirements of the working conditions, engineers have designed three main types of synchronization methods.
Method One: Series connection - like a relay race, "one after another"
Series connection is the most intuitive synchronization method. Multiple pumps are connected end to end, with the outlet of the first pump connected to the inlet of the second pump, and so on.
Working principle: The slurry passes through the first pump for one compression, then enters the second pump for another compression, with the pressure stacking layer by layer. If each pump's lift is 50 meters, three pumps in series can achieve a total lift of 150 meters.
Advantages: The lift doubles, suitable for long-distance transportation or high-drop working conditions.
Disadvantages: High pressure-bearing capacity is required for the pumps, especially the ones in the middle and later sections, which must be able to withstand the accumulated high pressure from the front. Additionally, any pump failure will cause the entire system to stop.
Typical application scenarios: Tailings transportation in mines, long-distance pipeline coal transportation, high-lift mine drainage.
Key precautions:
• The flow rates of each pump in series must match; otherwise, there will be a situation where "the big pump drags the small pump"
• The shell strength and shaft seal grade of the later-stage pumps should be higher than those of the earlier-stage pumps
• Start by turning on the first pump at the front end, and then start them sequentially from back to front to prevent back pressure
Method 2: Parallel connection - "Each goes its own way" like multiple lanes
In parallel connection, the inlets of multiple pumps are connected to the same main pipe, and the outlets also converge to another main pipe. Each pump operates independently without interfering with each other.
Working principle: Each pump sucks water from the main pipe, pressurizes it, and then merges into the outlet main pipe. The total flow rate is equal to the sum of the flow rates of each pump. For example, if two pumps with a flow rate of 500 cubic meters per hour are connected in parallel, the total flow rate theoretically can reach 1000 cubic meters per hour.
Advantages: Flow can be flexibly adjusted. When the demand is high, more pumps can be started; when the demand is low, some pumps can be shut down, resulting in significant energy savings. Moreover, when one pump is under maintenance, the other pumps can continue to operate.
Disadvantages: The head cannot be added together. The total head is equal to the head of a single pump. Additionally, if the performance curves of the pumps vary too much, there may be a "race for water" phenomenon, causing some pumps to operate at an overload.
Typical application scenarios: Large water supply systems, circulating water systems, sewage treatment plant inlet pump stations.
Key precautions:
The head characteristics of each pump in parallel connection should be as consistent as possible to avoid excessive performance differences.
The diameter of the outlet main pipe should be large enough; otherwise, back pressure interference may occur.
A check valve should be installed at the outlet of each pump to prevent slurry from flowing back when the pump stops.
Method 3: Series-Parallel Combination - Both Head and Flow Required
When dealing with a situation where both high head and large flow are needed, simply using series connection or parallel connection is not sufficient. At this point, a "combined approach" must be employed - a mixed configuration of series and parallel connections.
Common solution: First, connect several pumps in series to form one group, and then connect multiple groups in parallel. For example, two groups of three pumps each connected in series and running in parallel is equivalent to both head addition and flow addition.
Working principle: Each series-connected pump is responsible for providing high head, while multiple parallel connections expand the total flow. This configuration is like a "matrix" and can be flexibly adjusted according to actual needs regarding the number of units started.
Advantages: Balances head and flow, highly adaptable.
Disadvantages: Significantly increases system complexity, requiring meticulous planning for pipeline design, valve configuration, and control systems, and also incurs higher investment costs.
Typical application scenarios: Large water diversion projects, long-distance high-concentration mineral slurry transportation, and water injection systems on offshore platforms.
