This report is from the China Council for International Cooperation on Environment and Development (hereinafter referred to as the “CCICEDâ€) “China Low Carbon Economy Development Path Research Groupâ€. The three core Chinese and foreign experts of the research group are Liu Shijin, deputy director of the Development Research Center of the State Council, Gordon Conway, chief scientist of the UK Department for International Development, and Bjorn Stigson, chairman of the World Business Council for Sustainable Development. ).
Liu Shijin said that the meaning of “carbon lock†is that industrial activities and economic scale have a huge inertia. By building an infrastructure with a life span of 50 to 100 years, a country’s technology and institutional structure are jointly toward a fossil fuel-based system. Evolution.
The analysis shows that China is currently in the process of rapid industrialization and urbanization, and a large amount of infrastructure and equipment are put into operation in the next 20 years. In the context of large-scale investment, if advanced technology, equipment and development concepts are not adopted, once completed, they will be locked in the path of high energy consumption, high pollution and high emissions throughout their life cycle.
Some experts here also worry that under the circumstances of the 4 trillion investment plan to stimulate economic growth, some projects with high energy consumption and high pollution emissions that have been revived for various reasons may further aggravate the “carbon lock†situation.
According to the report, the reasons for the formation of environmental problems in China are complicated, but among many factors, the energy utilization status that has been “carbon-locked†includes the rapid growth of total energy consumption, coal-based energy structure and low utilization efficiency. .
“Traditional construction and production models are extensive and inefficient, resulting in high-intensity pollutant emissions.†The report said that although China has achieved significant results in energy efficiency improvements over the past 20 years, the annual average energy savings rate has reached About 4%, but the comprehensive energy consumption is still only about 30%, about 10% lower than that of developed countries.
In terms of energy intensity, China's energy consumption per unit of GDP fell from 11.9 standard coal tons per 10,000 US dollars in 2005 to 10.48 standard coal tons per 10,000 US dollars, but it is still 5 to 7 times that of developed countries.
"So, we should start to develop a low-carbon economy as soon as possible, adopt advanced production technology and equipment, rational urbanization mode and economical consumption mode in development, and embark on the development path of low energy consumption, low pollution and low emissions." World Jin said.
The scenario analysis of the research team shows that if China does not change its economic development model, per capita carbon dioxide emissions will reach 8 tons by 2030, and oil dependence will exceed 80%. And if China takes a low-carbon development path, China can reduce its energy consumption by 20% in 2030 to 4.47 billion tons, and the per capita carbon dioxide emissions are 5.9 tons.
A ball check valve is a check valve in which the closing member, the movable part to block the flow, is a spherical ball. In some ball check Valves, the ball is spring-loaded to help keep it shut. For those designs without a spring, reverse flow is required to move the ball toward the seat and create a seal. The interior surface of the main seats of ball check valves are more or less conically-tapered to guide the ball into the seat and form a positive seal when stopping reverse flow.
Ball check valves are often very small, simple, and cheap. They are commonly used in liquid or gel minipump dispenser spigots, spray devices, some rubber bulbs for pumping air, etc., manual air pumps and some other pumps, and refillable dispensing syringes. Although the balls are most often made of metal, they can be made of other materials, or in some specialized cases out of artificial ruby. High pressure HPLC pumps and similar applications commonly use small inlet and outlet ball check valves with both balls and seats made of artificial ruby, for both hardness and chemical resistance. After prolonged use, such check valves can eventually wear out or the seat can develop a crack, requiring replacement. Therefore, such valves are made to be replaceable, sometimes placed in a small plastic body tightly-fitted inside a metal fitting which can withstand high pressure and which is screwed into the pump head.
There are similar check valves where the disc is not a ball, but some other shape, such as a poppet energized by a spring. Ball check valves should not be confused with Ball Valves, which is a different type of valve in which a ball acts as a controllable rotor to stop or direct flow.
A diaphragm check valve uses a flexing rubber diaphragm positioned to create a normally-closed valve. Pressure on the upstream side must be greater than the pressure on the downstream side by a certain amount, known as the pressure differential, for the check valve to open allowing flow. Once positive pressure stops, the diaphragm automatically flexes back to its original closed position.
A swing check valve or tilting disc check valve is check valve in which the disc, the movable part to block the flow, swings on a hinge or trunnion, either onto the seat to block reverse flow or off the seat to allow forward flow. The seat opening cross-section may be perpendicular to the centerline between the two ports or at an angle. Although swing check valves can come in various sizes, large check valves are often swing check valves. The flapper valve in a flush-toilet mechanism is an example of this type of valve. Tank pressure holding it closed is overcome by manual lift of the flapper. It then remains open until the tank Drains and the flapper falls due to gravity. Another variation of this mechanism is the clapper valve, used in applications such firefighting and fire life safety systems. A hinged gate only remains open in the inflowing direction. The clapper valve often also has a spring that keeps the gate shut when there is no forward pressure. Another example is the backwater valve (for sanitary drainage system) that protects against flooding caused by return flow of sewage waters. Such risk occurs most often in sanitary drainage systems connected to combined sewerage systems and in rainwater drainage systems. It may be caused by intense rainfall, thaw or flood.
A stop-check valve is a check valve with override control to stop flow regardless of flow direction or pressure. In addition to closing in response to backflow or insufficient forward pressure (normal check-valve behavior), it can also be deliberately shut by an external mechanism, thereby preventing any flow regardless of forward pressure.
A lift-check valve is a check valve in which the disc, sometimes called a lift, can be lifted up off its seat by higher pressure of inlet or upstream fluid to allow flow to the outlet or downstream side. A guide keeps motion of the disc on a vertical line, so the valve can later reseat properly. When the pressure is no longer higher, gravity or higher downstream pressure will cause the disc to lower onto its seat, shutting the valve to stop reverse flow.
An in-line check valve is a check valve similar to the lift check valve. However, this valve generally has a spring that will 'lift' when there is pressure on the upstream side of the valve. The pressure needed on the upstream side of the valve to overcome the spring tension is called the 'cracking pressure'. When the pressure going through the valve goes below the cracking pressure, the spring will close the valve to prevent back-flow in the process.
A duckbill valve is a check valve in which flow proceeds through a soft tube that protrudes into the downstream side. Back-pressure collapses this tube, cutting off flow.
A pneumatic non-return valve.
Multiple check valves can be connected in series. For example, a double check valve is often used as a backflow prevention device to keep potentially contaminated water from siphoning back into municipal water supply lines. There are also double ball check valves in which there are two ball/seat combinations sequentially in the same body to ensure positive leak-tight shutoff when blocking reverse flow; and piston check valves, wafer check valves, and ball-and-cone check valves.
Check Valves, Water Check Valves, Brass Check Valves, Sanitary Check Valves
ZHEJIANG KINGSIR VALVE CO., LTD. , https://www.kingsirvalves.com