Perforated annular positioning flow choking device

Abstract

The invention relates to a perforated annular positioning flow choking device which is used for matched positioning and flow choking of an automatic underwater washing device of a seawater buoyancy raft culture net cage. Circular holes are uniformly perforated on a cloth piece of the existing 'annular positioning flow choking device'. The perforated annular positioning flow choking device is mounted on a partition at the bottom of the net cage in a sleeving manner. The diameter of an outer ring of the perforated annular positioning flow choking device of the net cage can be set according to a principle that a swing angle of the net cage is directly proportional to a tidal flow speed and an effective stressed area of the net cage; if a tidal flow of a culture sea region is large, the diameter can be small; on the contrary, the diameter can be large. The perforated annular positioning flow choking device can generate a choked flow opposite to a moving direction of the net cage by the action of sea waves when the tidal flow approaches to zero, and the net cage is basically perpendicular to the surface of a sea, and the choked flow can impact a net scraper to move towards the top of the net cage through the circular holes in the annular positioning flow choking device. The perforated annular positioning flow choking device has the advantages that application sea range of automatic underwater net cage cleaning technologies is widened effectively.

Description

technical field [0001] The invention relates to matching positioning and flow blocking of an underwater automatic cleaning device for seawater floating raft culture net cages. Background technique [0002] At present, a number of patented technologies and products such as "a method and device for automatic cleaning of net cages under water" have been applied in production. Concrete method all is that a kind of annular float net scraper (hereinafter referred to as net scraper) is set on the net cage and makes it can not break away from the net cage up and down. The basic principle is: when there is no tide, the net cage is perpendicular to the sea surface and floats to the top of the net cage by its own buoyancy. As the tide continues to increase, the net cage will swing to the direction of the tide. When the swing angle reaches a certain level, The net scraper moves to the bottom of the cage under the pull of the tide (such as Figure 3-1 , Figure 3-2 , Figure 3-3 ). P...

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Problems solved by technology

Practice has proved that the swing angle of the net cage is proportional to the tidal flow velocity and the effective stress area of ​​the net cage, so the existing aquaculture net cage can only swing at a small part of the aquaculture sea area where the tidal current velocity is greater than 50 cm / s. At a certain level, 80% of the tidal current velocity in the aquaculture sea area cannot pull the existing aquaculture cages to a certain level, so that the new technology of automatic underwater cage cleaning cannot be implemented on a large scale

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