Shenzhen News Network April 22 hearing on the subway security "pass the field" question raised a few days ago to discuss users, the reporter had in the news on April 15 in the car column headlines issued a "MTR rush hour security screening was alleged loopholes netizens Tucao waste The "time" report attracted the attention of the subway company. On April 21st, Zheng Huilong, the deputy minister of Shenzhen Metro’s Operation and Management Office, was interviewed by a Shenzhen News Network reporter in the office and responded to the questions raised by netizens one by one.
Question 1: Metro security has no effect, only for the public security inspection?
Subway company: More than 90,000 items of inflammables and explosives have been seized and nearly 60,000 pieces of controlled tools have been found
According to Zheng Huilong, nearly 3 million citizens (excluding MTR Line 4 data) travel by subway every day. Occasionally, some commuters will consciously or unconsciously carry some prohibited articles and dangerous goods into the subway station, causing safety risks to passengers. Metro stations, especially trains, serve as public gathering places, and the space is relatively closed. In the event of a terrorist incident, the damage, loss, and social impact will be greater. Therefore, the government decided to implement security inspections in subways in order to minimize and prevent such risks.
From the implementation of the comprehensive security inspection on March 7, 2014 to April 15, 2015, the total number of personnel inspected by Shenzhen Metro has been nearly 500 million. More than 15 million contraband items were seized. Among them, more than 90,000 items are flammable and explosive, and nearly 60,000 pieces of controlled tools are used. Among them, more than 20 controlled knives and several dummy guns were seized at one time in Shenzhen North Railway Station. More than 10 daggers were seized at Chegongmiao Station at one time, and several live ammunition were seized at the exhibition center station. Other sites seized a lot of alcohol, Tinner, etc. Flammable and explosive products. Metro security has played a positive role in filtering social security risks and reducing security risks in subway stations and trains.
Anti blocking regulating valve
Valve blockage is one of the common faults, especially when mud, pulp, pulp, caustic soda, or carbonized occasion are blocked. Except that the medium is not clean, the plug in the pipe will cause plugging. Therefore, it is necessary to have better anti blocking function, but there are no plugging valves at present, so it can only be considered from all aspects to improve its anti blocking function.
Anti blocking regulating valve
Selection of 1. valve flow patterns
A: from the structural point of view, the flow path of the straight stroke is S streamlined and the flow path is complex. So the anti blocking performance must be bad. Take the single seat valve as an example, after the medium flows into the valve from the horizontal direction, it flows vertically and flows out again. It can be seen that the complex flow of turning and turning can produce a lot of whirlpool dead zones, providing a precipitable space for the medium, so it is very easy to block up; from the combination of the sleeve and the valve plug, the gap between the two is small, and some unclean things will cause the jam. Look at the old single seat valve and the double seat valve. The direction of the lower cover is a dead zone where the medium precipitates. Precipitated things are easy to accumulate, causing the valve core to move downward very difficult, and valve blocking is not in place.
B: the angle stroke valve overcomes the problem that the flow path of the direct stroke valve is complicated and the upper and lower guide card is easy to plug in. The valve of the medium through the angle stroke seems to be straight out, the most typical "O" type, just like straight pipe, its anti blocking performance is the best, and the second is the eccentric rotary valve.
Selection of 2. type of throttling
When the medium flows through the throttle, under the same throttle area condition, if the throttle gap is small, the clean medium is not easy to pass through, so it is easy to clog; conversely, it is not easy to block. For the plunger type valve core, the throttle area is evenly distributed on the circumference, so the gap is the smallest; and then the window type valve core has the throttle area on the window, so the gap is larger than the plunger type, and the particles are easier to pass through. It can be seen that the more concentrated throttling area and the larger the throttling gap, the better the anti blocking performance. Such a typical product has a "V" type. Especially in the small opening work, the "V" type of throttling area is more concentrated, and more difficult to block the card, which fully demonstrates the "V" type of anti blocking advantages.
3. common measures for anti blocking:
In addition to improving the traditional flow path and improving the linear flow prevention measures, some anti blocking measures can be adopted for the medium, such as pulp, pulp, slurry, pulp and other media.
1) the smooth flow of the flow, the more balanced the better the transition. In view of the advantages of high concentration of thick slurry, poor fluidity and easy settlement, the direct through shell structure is adopted to minimize flow resistance and prevent blockage (that is, the diameter of the shell flange, and the outlet is larger than the import). This measure is very effective for thick slurry and other occasions.
2) according to the calculation, if necessary, the valve seat diameter can be reduced to improve the flow speed of the throttle port so as to improve the "self-cleaning" function of the valve itself.
3) add punching and sweeping interface before the valve seat, and use high pressure air or water to clean and block the inner cavity of the shell.
4) use an actuator with sufficient torque and strength.
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