Chen Xin didn't plan to dismantle the equipment of his own shelter, so he had to collect additional resources or make parts for the vehicles to rebuild.

Fortunately, he has a workbench, and he can process some of the parts of the materials needed to transform the vehicle by himself, and the main thing that he really needs to exchange and collect is some raw materials and materials that are more cumbersome to process by himself and are more convenient to collect by exchanging.

Among them, such as car parts, cold-proof materials, and various steel materials needed for vehicle modifications, Chen Xin had to be obtained through exchanges with Li Yulong and the SWAT team.

But for example, he can make other materials such as shock springs, track parts, water circulation devices, etc., and all that is consumed is a small amount of survival points and raw materials.

However, most of the raw materials that Chen Xin stockpiled were prepared for the planned overall upgrade of the shelter, most of which were building materials such as cement and steel bars, and the rest were mostly heat insulation boards and the like.

There aren't many high-performance steels used to make shock springs and track parts, and only a few steel plates are intended to be used to reinforce the structure of the shelter.

"So I have to collect a batch of steel!" Looking at the list of materials, Chen Xin sighed helplessly.

Although there is a system, even the simplest metal materials can be used as raw materials, or even non-metal materials, but considering the cost and input issues, as well as the subsequent use, Chen Xin feels that it is more appropriate to get a batch of steel.

Fortunately, in addition to these parts that require metal materials to be processed, things such as water recycling devices do not require a lot of metal materials, although it is better to make them with metal materials, and they can also be replaced by other materials.

So Chen Xin decided to use the existing materials at hand to make everything that could be done, and see if he could make some low-level substitutes if he couldn't do it, and then make up for it with survival point upgrades.

Although the function of the system upgrade is powerful, the consumption of survival points is not a small amount, although he currently has close to five-digit survival points, but according to the various consumption listed on the list, if Chen Xin uses the system functions to make these things without any scruples, the survival points in his hands will be used up at least more than one-fifth.

So if you can save, you still have to save.

It is not too difficult to make a water recycling device, and it does not require too much material, and the most important thing is the recycling of waste water and sewage, as well as the recycling of purified treatment.

There is no need to worry about the recycling of waste water and sewage, and the water recycling system can be completed by the pipes in the water area when the water circulation device is installed on the vehicle, and the real focus is on purification.

Simple sewage purification treatment is not complicated, only need to use activated carbon, sand and other materials to precipitate and filter the sewage.

However, such a simple filtration effect is not good, and the chemical pollutants and heavy metal ions that may remain in the sewage will not be separated because of such a simple filtration.

Chen Xin has purchased portable filters necessary for survival in the wild, and has also dismantled the structure inside the research.

In addition to the basic sand and activated carbon filtration, the most important thing is the filter membrane, which can effectively filter bacteria and other harmful substances in the water, so that the original sewage can be restored to a drinkable level.

In the past, Chen Xin used this portable water purification filter when he was playing wild survival, and when it was difficult to find a clean water source or when the water could not be boiled for drinking due to the lack of boiling water conditions, this filter was indeed a very convenient device, and it was easy to obtain clean drinking water.

This filter is used as a water purification component of the water circulation device, which is not overkill, but it is more than enough.

However, Chen Xin did not directly use his portable filter as a component to make a water circulation device, nor did he disassemble it to obtain parts, but planned to make it himself.

Saw a section of PVC pipe as the main body, cut off some more pipes as auxiliary materials, use the system processing function to transform the structure, turn the pipe as an auxiliary material into an end cover, and the rest is to fill the pipe as the main body with filter material.

The filter membrane material is special, Chen Xin does not have it at hand, although it is not impossible to do it with the help of system functions, but Chen Xin does not need to be so troublesome.

Since you want to borrow system functions, why not just upgrade them?

After filling the sediment and charcoal into the main body of the filter he had made, Chen Xin compared the consumption required to make the filter membrane and directly upgrade the filter, and decisively chose to upgrade directly.

After all, this is just a small thing, and it costs 10 survival points to make the filter membrane by yourself, but it only needs to consume 15 survival points to upgrade it directly, and you only need to add a little material to it.

After upgrading the homemade filter to the same level as the portable filter he bought, Chen Xin used the filter as a water purification component and assembled it into the same homemade water circulation device.

In this way, the water circulation device, which is one of the important components of the vehicle retrofit, is completed.

Ticking a box on the list, Chen Xin looked at the materials and parts listed on the list, thinking about what he was going to do next.

But just as he was thinking, his radio suddenly went on.

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At this time, outside the door of Chen Xin's shelter, a police armored car was parked in front of his house.

"Chen Xin said that he would open the door immediately." In the car, a SWAT team member put down the walkie-talkie in his hand and reported to Li Tou and a person sitting next to him who was not wearing a police uniform and looked like an official.

Both nodded, not saying anything more about it.

Although Li Tou's team was not only hospitalized with injuries due to previous operations, but also several other team members were also injured and treated in the hospital, even if there was a lack of manpower, they were still sent out to carry out the investigation of unofficial shelters with the staff of the joint investigation team under the current situation of large-scale mobilization of the whole city.

"Here lives a member of the public who cooperates with our SWAT team, and he mainly provides fresh vegetables for our SWAT team in exchange for some survival materials, we have come to investigate before, and there is no suspicion." Li Tou explained the situation to the official-looking person next to him, but he was obviously helping Chen Xin say good things to avoid the possibility of Chen Xin being suspected.

"Of course, the work of the comrades of the city bureau is trustworthy, but the joint investigation team decided to conduct a second investigation, or it is safer to check it again." The official-looking person bowed slightly, and did not make any obvious reaction to Li Tou's words.

But looking at his demeanor, Li Tou also understood that he listened to his words.