Single opening of the quick-opening damper

This should be brought under better control; however, self-switching devices must be installed on several dampers, so that the controller can operate the valves when the fan starts or stops

As far as I understand, you haven’t worked with instruments before, but I think there are the following solutions: To achieve these functions, you can use various approaches, which require the cooperation of on-site instruments and a DCS system. The specific method to choose depends on your needs: 1. If you simply want to reduce the number of valve operations – for example, if the design calls for 5 valves to be open at once, but you only want 3 to be open – then you can make modifications to the valve itself. For instance, you can block the exhaust valve of the two-position three-way solenoid valve (this can be done by sealing it with screws at the insect-proof and noise-reducing section). In this way, even if the solenoid valve loses power and stops functioning, the gas inside the cylinder cannot be released, preventing the valve from closing. 2. Interlocking is achieved through two-position three-way (or currently, two-position five-way) solenoid valves. It is possible to modify the interlocking air circuit by adding another solenoid valve, using two solenoid valves in parallel. In this case, both solenoid valves must lose power simultaneously for interlocking to occur. One solenoid valve can be controlled by the SIS, while the other can be manually de-energized via the DCS to achieve the desired function. 3. An interlocking bypass can be added using the SIS; for example, if there are 5 quick-opening valves and only 3 need to be opened at a time, interlocking confirmation switches can be added in the SIS for those two valves. This is equivalent to adding an ‘OR’ switch. During interlocking, manual confirmation is required (which corresponds to setting a value of 0); once confirmed, interlocking takes place. If no confirmation is given, even if the interlocking signal is 0, the ‘OR’ switch remains at 1, so the output value stays at 1 and interlocking does not occur. 4. Of course, there are also simpler methods, such as physically locking the valve stem that controls the valve in place

This post was last edited by 328104062 on 2017-2-12 at 20:13. Personally, I recommend using option 3, as the other options violate relevant regulations. Even using option 3, adding a bypass to the output also violates Sinopec’s safety instrumented system interlock regulations. Another approach is to use 5 quick-opening valves, but only activate 3 of them; the remaining two should be operated manually via the DCS. This would require adding positioners and signal wires, while the original solenoid valves and power supply can be removed. In this way, if the oxygen level is insufficient when all 3 valves are open, it is possible to manually control the valves through the DCS. This is the best solution, as it also allows for some degree of adjustment, provided that you re-evaluate the SIS interlock circuit

Adding a simple PLC will do.

There should be a PLC on site; just modify the program.