What is this on the main steam pipeline entering the plant in the park?

Inverted-mounted self-acting pressure regulators are commonly found in steam pipelines

Installation method of self-acting control valves: 1. Provision of a straight pipe section for the self-acting control valve – A certain length of straight pipe should be maintained before and after the self-acting pressure control valve (usually around 6D, where D is the pipe diameter). The distance from the valve to the pressure tapping point before the valve should be greater than 2D; the distance for pressure tapping after the valve should be greater than 6D. Pressure gauges should also be installed before and after the valve, and they should be placed close to the pressure sampling point so that the set value matches the actual pressure reading accurately. ⒉Installation of a bypass system for self-acting control valves: To ensure that production can continue to operate during maintenance or in the event of a failure, it is advisable to install a bypass system. 3. Installation of the self-acting control valve filter: In this system, the filter can be omitted when the process medium is clean and free of impurities. When there are impurities in the medium or a self-acting pressure control valve with a pilot is used, a filter should be installed to prevent blockages in the pressure sensing lines or the pilot, as well as to avoid jamming of the cylinder actuator and the valve core. If space for pipeline installation or budget is limited, the filter screen can be installed upstream of the stop valve before the valve. Replace the filter. 4. Relationship between the installation method of self-acting control valves and the medium and temperature 1) In principle, for self-acting pressure control valves, the gas medium should be installed in an upright position (with the actuator at the top and the valve body at the bottom), while liquid and steam media should be installed in an inverted position. 2) When the temperature of the gas medium is above 70°C and below 140°C, or when the temperature of the liquid medium is above 140°C, in addition to being installed in an inverted configuration, the self-acting pressure control valve should also be equipped with a isolation tank on the pressure tapping line; moreover, the pressure tapping line, the isolation tank, and the diaphragm head should all be filled with a refrigerant to prevent the diaphragm from aging due to high temperatures. 3) When the temperature of the gas medium is above 70°C and below 140°C, if vertical installation is still used, it is necessary to specify in the design documents (equipment list) the use of high-temperature diaphragms (such as EPDM diaphragms, silicone rubber diaphragms, etc.); otherwise, the ordinary diaphragms will age.