Biogas digesters are a kind of container for biogas concentration. Biogas is an organic matter in the anaerobic environment, in a certain temperature, humidity, pH conditions, through the microbial fermentation, resulting in a combustible gas. Since biogas was originally found in swamps, lakes and ponds, it is called biogas.

With the development of biogas technology in China and the popularization of biogas in rural areas, according to local requirements and temperature, geology and other conditions, the household biogas digesters have a fixed arch of hydraulic pond, large cover hydraulic pond, Hydraulic pond, meandering cloth hydraulic pond, the top back to the water pressure pond, separate floating shroud pool, semi-plastic pool, plastic pond and tank-type pool. Although the form of a wide variety, but in general by the total pressure by the digesters, floating cover type digesters, semi-plastic biogas digesters and tank type of the four basic types of changes in the formation. Biogas digesters with four-in-one ecological greenhouses are generally of the hydraulic digester type and are available in several different forms.

Hydraulic digesters, is pool type that first one and largest number to be promoted in China.It iscreated by concluding that the "three-in-one", "round, small, shallow", "movable cover", "straight pipe feed", "middle discharge" And other basic of general public with comprehensive increasing . "Three combined" is the toilet, pigsty and biogas digesters connected into one, human and animal waste can be directly cleaned to the digester for fermentation. "Circle, small, shallow"means the pool body is round, small size, shallow depth of burial. "Activity cover" is the biogas digger with top removable cover.

Hydraulic digester type has the following advantages:

(1) body structure of the force performance is good, but also make full use of the carrying capacity of soil, so the cost of the labor and material is relatively low.

(2) suitable for filling a variety of fermentation raw materials, especially a large number of crop stalks, very beneficial to the rural fertilizer.

(3) in order to facilitate regular feed, toilet, pigsty can be built on above of digester,stool can be cleaned into the pool at any time.

(4) digesters around contact with the soil, the pool has a certain role in heat preservation.

Hydraulic digester type also has some shortcomings,like:

(1) because of repeated pressure changes, and generally 4 to 16 kPa (ie 40 ~ 160 cm Hg) between the pressure changes,there have a negative impact for the pool strength and lighting, stability and improvement of stove combustion efficiency.

(2) In the absence of mixing device, the pool of scum is easy to crust, and difficult to break, so the utilization of fermentation raw materials is not high, pool capacity gas production rate (ie, cubic meter per day volume of gas production) is low, the general gas rate Only about 0.15 m 3 / m 3 per day.

(3) As the diameter of the movable cover can not be increased, for biogas digesters that the fermentation raw materials is straw-based, the material outlet work is more difficult. Therefore, the material outlet work is better to use the material outlet machinery.

The main features for hydraulic molding press for making this products are shown as following:

1. Machine has high daylight and stroke, it is easy to move in and move out.

2. With fast down speed, pressing speed and up speed.

3. Optimizing the total power,by using accumulator, it can have energy saving and environmental protection.

In Taitian, Hydraulic composite molding press has take over 50% in amount of sales.With the four corner parallelism control system,it can solve the technical problems such as the partial load caused by the asymmetry of the forming parts and the deviation of the thickness of the large flat thin products, which can meet the process requirements of in-mold spraying (IMC), parallel demolding.This kind of press machine can be applied in compression moulding of SMC sheets and moulding of various plastics.