The toxicity of the medium, as well as its flammability and explosiveness, have an impact on the selection of chemical pumps
Thread Content
When transporting toxic, flammable, and explosive substances, choosing the wrong type of seal can lead to accidents – not just minor leaks, but full-blown disasters! For highly toxic, highly corrosive, flammable, and explosive substances such as liquid chlorine, acrylonitrile, and benzene, magnetic pumps or shielded pumps are the preferred choice; they provide complete sealing without moving parts, resulting in theoretically zero leakage, but they are expensive and require complex maintenance. For flammable and explosive media such as hydrocarbons, methanol, toluene, and those containing trace amounts of H2S, the industry-standard solution is a double-end face mechanical seal combined with a flushing system; Plan52, Plan53A/B – involving the circulation of buffer fluids and isolation fluids – ensures that leaks can be controlled, and online monitoring and alarm functions are available. Plan54 — External cleaning solution, dual protection for greater safety. In the case of gas systems, such as ethylene or natural gas, dry gas seals can be used; they result in almost no leakage, low friction, and a long service life. However, a stable gas supply is required, and the cost is high. Single-face sealing is only suitable for media that are non-toxic, non-flammable, and pose a low risk. Toxicity of the medium, flammability and explosiveness, sealing solutions, selection table for flushing systems
Medium toxicity and flammability have a significant impact on the selection of chemical pumps; choosing the wrong seal can lead to serious accidents. Brief summary: – **Highly toxic, highly corrosive, flammable, and explosive substances** (such as liquid chlorine, acrylonitrile, benzene): **Magnetic pumps or shielded pumps** are preferred, as they provide complete sealing to prevent leaks; however, they are expensive and require complex maintenance. - **Flammable and explosive media** (such as hydrocarbons, methanol, toluene, with trace amounts of H₂S): The standard solution is a **double-end face mechanical seal + flushing system**: - **Plan 52/53A/B**: Uses buffer/isolation fluid circulation; leakage is under control and online monitoring is possible. - **Plan 54**: External cleaning solution for extra safety, a dual safeguard. - **Gaseous media **(such as ethylene, natural gas):** **Dry gas seals** can be used; they result in almost no leakage and have a long service life, but they require a stable gas supply and are costly. - **Low-risk media** (non-toxic, non-flammable): A **single-end seal** is sufficient. In short: **For high-risk media, advanced seals (magnetic pumps, double-end face seals, etc.) must be used, while ordinary seals are sufficient for low-risk media**. Safety first – don’t skimp on seals! .