1 mines that cannot use the open-air mining method of wind-flow ventilation, or mines with fewer stages of operation at the same time;
2 mines with large ventilation resistance, large air leakage points or wide distribution areas in production operations;
3 The existing wells can be used as special intake wind tunnels, and mines with little interference between the air intake lines and the transportation lines.
  The use of multi-stage station ventilation systems should meet the following requirements:
The level 1 station should be less, the wind section should be 1 level, and the inlet and return sections should not exceed 2 levels;
Fan for the stations 2 and the front and rear units per branch should match the same; fan of the same stations, the model should be the same size; Number of stations fan units is suitably 1 to 3 sets of units;
3 The characteristic curve of the fan should be monotonically decreasing, and there should be no obvious saddle type;
4 access roads should be provided with duct ventilation;
5 multi-stage station ventilation system should adopt centralized control.
1. No space for hammock?
No problem. Hammock chairs are ideal for front porches, small patios, decks, indoor nooks, bedrooms and for hanging from that small shade tree in the garden. Even when used in conjunction with a hammock chair stand, they have a small footprint and don`t take up a lot of room.
2. Mobility
You can secure a hook for hanging a hammock chair in more than one spot around the house and simply move it to wherever you need it, whenever you need it. Combining it with a hammock chair stand can offer an even easier solution. Both are generally lightweight and can be moved with the greatest of ease.
3. Your Health
Therapists and patients are using hammocks chairs and swing chairs due to the health benefits involved. Hammock chairs and swing chairs might just be the thing you need to relieve that pain in your lower back or neck. The hammock chair adjusts and moulds with the weight of your body, providing support to the body and removing pressure points.
4. Easy installation
No contractors are needed. You can do this! A tree limb, porch beam or chair stand is all you need for outdoor installation.
5. They`re a versatile gift
Most people don`t have a hammock chair or hammock swing. Most don`t truly realise the benefits that they can offer and the relaxation that they can bring – get them one.
Hammock chairs and hammock swings can be a great addition to your home, garden or even campsite. They`re versatile and convenient, not to mention, stylish and practical. Go on, give one a try.
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Ningbo Autrends International Trade Co., Ltd. , https://www.outerlead.com