Water Circulation Purification System in Swimming Pool
A. Purpose of Water Circulation in Swimming Pool
In line with the national technical policy of saving water resources, energy and protecting the environment;
Ensure that the purified water can reach all parts of the swimming pool in an orderly manner, so that the pool water is always clear and clean;
B. Water circulation in swimming pool
Swimming pool water circulation means that the inflow and return water of the swimming pool flow continuously in the pool. Generally speaking, it is necessary to solve the problem of where to take water from the pool (i.e. backwater) and where to put the purified water into the pool, so that it can be effectively removed. Floating on the dirty surface water of swimming pool can minimize the existence of sedimentary pollution at the bottom of swimming pool, which is the main principle of choosing the water circulation mode of swimming pool.
Swimming pool water circulation can be divided into three types: downstream, countercurrent and mixed flow.
1. Downstream
The whole circulating water of the swimming pool is fed into the pool through a water supply outlet set at the end of the pool or below the water surface of the side wall, which is then retrieved by a backwater outlet set at the bottom of the pool, and then treated and sent back to the pool for further use.
Advantages:
Civil structure requirements are low, the cost is lower than countercurrent and mixed flow type;
Pipeline layout is simple, the number is small, no investment in balanced water tank and other redundant equipment, convenient management and maintenance, less investment;
The computer room occupies a small area, and the elevation requirement is 1 meter lower than the swimming pool surface.
Disadvantages:
The pool water at the lower part of the intake can not be recycled effectively. Distribution of water is not as uniform as countercurrent, which results in uneven water quality in the pond;
Overflow of overflow tank is discharged entirely and wastes more water;
The negative pressure of water absorption at the bottom of the pond is relatively high, which is relatively dangerous and easy to cause human body or hair to be absorbed by the backwater outlet and cause damage, so the pre-design needs to consider solutions.
2. Countercurrent
It refers to the water circulation of the swimming pool, which is fed into the swimming pool through the water supply nozzle or trough at the bottom of the pool, and then recovered by the overflow trough on the outside of the wall of the pool. After water treatment, the water flow is sent back to the pool for continued use.
Advantages:
The uniform distribution of water supply outlets at the bottom of the pond can satisfy the uniformity of water flow in the pond and prevent eddy current, short flow and dead water zone;
The dirty impurities on the surface of the pond can be collected through the overflow tank and enter the water treatment system, which can effectively purify the surface water of the pond and suspended substances. There are more outlets and fewer sediments at the bottom of the pond.
Ensure that the water quality (cleanliness, disinfection allowance, PH value and water temperature) in different water layers and different parts of the pond are uniform.
Disadvantages:
Higher construction cost;
Balanced water tank is needed, the machine room occupies a larger area, and the height requirement of the machine room is about 3M below the surface of the swimming pool to ensure overflow backwater and high investment;
Water distribution at the bottom of the pool is more difficult, the pipeline is more than downflow and the overflow pipe diameter is more demanding, the construction, installation and maintenance are more difficult;
Noise in the overflow trough is more difficult. The sound is louder.
3. Mixed flow
It refers to all the circulating water in a swimming pool. 75%~80% of the water is retrieved through the overflow backwater outlet located on the outside of the pool wall. Another 20%~25% of the water is retrieved from the backwater outlet at the bottom of the pool. After the two parts of circulating water are combined for water treatment system, the water flow organization mode which is continued to be used in the swimming pool is sent into the swimming pool through the water supply port located at the bottom of the swimming pool.
Advantages:
It not only has the advantages of counter-current pond water circulation mode, but also has the advantages of downstream pond bottom backwater that can rely on current to wash away and take away sediment from the bottom of the pond. Although there are few examples of this method in China, it is known that the effect is satisfactory.
Disadvantages:
Construction costs are high. Machine room construction has the same basic and countercurrent requirements, with large space occupied and high investment;
Real flow distribution of pond bottom and overflow backwater is difficult to control reasonably;
Noise in overflow trough is larger;
Pipeline construction is similar to countercurrent construction, which requires more pipelines than downflow and more overflow pipe diameter, and is more complex than countercurrent construction. More than one backwater main pipe should be led to the engine room;
The backwater pipe at the bottom of the pool is connected with the suction pipe of the balanced water tank, and the backflow is prevented by the check valve. According to practical experience, if there is a slight problem with the check valve, the probability of water leakage to the water tank is very high, resulting in a large amount of water waste, or even inundation of the engine room.
