What should be the distance between the target sheet in steam target shooting and the pipe outlet?

We are using 400MM.

If it is low-pressure steam and the pipe diameter is small, the target testing can be carried out directly 100 mm outside the pipe outlet； In the case of medium or high-pressure steam or large pipe diameters, it should be installed directly after the vent pipe and secured using flanges.

For both medium-pressure and low-pressure steam, a specialized target frame (machined from steel) and a target plate (with a thickness of 5–8 mm and a width of 20–35 mm) are welded into the pipe at the end of the pipeline where targeting is required, prior to installing a silencer; aluminum strips are also custom-made depending on the diameter of the pipe.

The Code for Construction and Acceptance of Industrial Metal Piping Engineering GB50235-97 does not specify a clear requirement regarding the distance between the installation target plate and the pipe end, but I believe the target plate should be installed directly on the pipe end.

Special target holders and target plates should be fabricated and fixed firmly to the straight section of the purge lead pipe to prevent flow deviation. It is better to install the target holder inside the tube, using an insert type that is secured with flanges. The target sheet has the same length as the inner diameter of the tube, and its width is 10% of the inner diameter.

The target sheet for steam shooting is fixed at the pipe outlet; there are no distance requirements, only requirements regarding the quality of the blowing.

200mm should be about right

Agree with the opinion from floor 7. “The target sheet for steam shooting is fixed at the pipe outlet; there are no distance requirements, only requirements regarding the quality of the blowing. ”The key is to meet the technical requirements and qualification standards for steam purging. Appendix: I. Technical requirements 1. High-pressure steam at 1.6 Mpa and 300℃ is used to purge the high-pressure steam pipeline network ； Low-pressure steam at 0.4 Mpa and 160°C is used to purge the low-pressure steam pipeline network. 2. Steam flow velocity ≥ 30 m/s. 3. The connection points to various devices must be sealed with blind flanges or disconnected; these flanges should be removed one by one when purging is required, to prevent gases containing impurities from entering other devices. 4. Purging is carried out in the order of the main pipe first, followed by the branch pipes. 5. Before purging, it is advisable to remove the valves on the main and branch pipes (regulating valves must be removed) and seal them temporarily; once the pipe section in front of the valves has been successfully purged, the valves can be reinstalled to proceed with purging the subsequent pipe sections. 6. Before purging each pipeline, it is necessary to first warm the pipeline and drain water, and then proceed with the purging. 7. During sweeping, a wooden hammer can be used to strike the pipe wall, causing the rust or slag that is difficult to blow away to fall off and be blown out. 8. Purge for 20 minutes each time, then stop the steam supply and allow natural cooling; tap the pipe with a wooden hammer. Once the temperature drops to room temperature, reheat the pipe, remove water vapor, and purge it again. Repeat this process until the pipe meets the required purification standards. II. Qualification Criteria 1. The effectiveness of pipeline purging can be checked using a target plate and a white cloth to assess the quality of the purging process. 2. Perform target plate replacement checks twice in a row, with a purging time of 1–3 minutes. If no traces of purging can be seen visually on the target plate, the purging is successful.