Although Penstocks and ordinary pipes both belong to fluid transportation equipment, they must be strictly distinguished in engineering selection due to essential differences in design positioning, structural strength, and application scenarios. The first scenario involves key transportation needs for high-pressure, high-flow rates and high reliability, whereas the second scenario emphasizes the requirements for low-pressure conventional systems.

I. Structural Differences: Design Logic Determines Functional Boundaries

1. Penstock: Tailor-Made for High-Pressure Working Conditions

Structural design centers on "pressure-bearing, impact resistance, and sealing," featuring high strength and precision:​

· Uses high-strength materials such as carbon steel, stainless steel, and fiberglass. The wall thickness is precisely calculated based on pressure levels and is formed through seamless welding or flange connections, reducing the risk of weld defects. A double-wall structure can be used for ultra-high-pressure conditions to enhance deformation resistance.

· Prioritizes welding connection to ensure joint strength; flange connection is equipped with high-strength bolts and sealing gaskets. Must integrate safety components such as pressure monitoring devices, pressure relief valves, and check valves. The inner wall is provided with anti-corrosion coating, and the outer wall is equipped with cathodic protection or a thermal insulation layer.​

· Uses a combination of fixed supports and sliding supports with dense spacing. Large-diameter models require concrete buttresses for reinforcement to prevent vibration or displacement caused by high-pressure fluid impact.

2. Ordinary Pipes: Focus on the Versatility of Low-Pressure Transportation​

Designed with "easy installation, low cost, and versatility" as the orientation, with a relatively simplified structure:​​

· Common materials include PVC, PE, ordinary carbon steel, and cast iron. Thin wall thickness, mostly formed by extrusion or casting. Plastic pipes adopt a socket connection without welding.

· Plastic pipes mainly use a socket or hot-melt connection; metal pipes use a threaded or simple flange connection. Joint sealing relies on rubber rings or ordinary gaskets, with limited pressure-bearing capacity.​

· Only requires basic valves to control on-off, without additional pressure relief or monitoring components. Anti-corrosion treatment is either minimal or absent entirely, making it suitable only for clean fluids at normal temperatures.

· Supports have large spacing and a simple structure, focusing on load-bearing without considering high-pressure vibration protection. Some buried pipes are installed directly in the soil without the use of special supports.

II. Pressure-Bearing Performance: Core Indicators Widen Application Gaps

1. Penstock: Outstanding High-Pressure Resistance and Stability

Design pressure typically ranges from ≥1.6 MPa to over 40 MPa. Sealing and strength are verified through hydrostatic testing, ensuring no leakage or permanent deformation as the standard for qualification.

Can withstand instantaneous fluid impact pressure, passing fatigue strength tests. Service life can reach 20-50 years without frequent maintenance.​

Can transport high-temperature, corrosive, particle-containing, and other complex fluids. Materials and coatings can be customized as needed to avoid corrosion or wear.

2. Ordinary Pipes: Low-Pressure Limitations and Performance Shortcomings​

Design pressure is mostly ≤1.0MPa. Conventional municipal water supply and drainage, and indoor water supply pipes have a pressure of only 0.2-0.6MPa. Exceeding the rated pressure is prone to leakage and rupture. Hydrostatic testing standards are lower than those of Penstocks.​

Poor resistance to instantaneous impact. Long-term high pressure or frequent pressure fluctuations are likely to cause loose joints and aging cracks in pipes. Service life is usually 8-15 years, requiring regular replacement.​​

Only suitable for normal-temperature, clean fluids. Corrosion and blockage are prone to occur when transporting corrosive or particle-containing media. Plastic pipes have the risk of high-temperature deformation.​

III. Application Scenarios: Precise Matching of Engineering Needs​

1. Core Application Scenarios of Penstocks​

Energy engineering, municipal water conservancy, industrial production, and special scenarios, such as hydropower station water diversion pipes, long-distance high-pressure water transmission projects, high-pressure feeding pipes in the chemical industry, and high-pressure water supply pipes in mine wells.

2. Typical Application Scenarios of Ordinary Pipes​

Municipal people's livelihood, construction engineering, light industrial production, and agricultural fields, such as urban water supply and drainage pipe networks, indoor water supply pipes in communities, clean water transmission in the food processing industry, and farmland irrigation pipes.​

To sum up, the essential difference between Penstock and ordinary pipes lies in the positioning distinction between "professional-grade high-pressure transportation" and "general-purpose low-pressure transportation". Selection must consider core indicators such as pressure, medium, environment, and service life to avoid cost waste or safety hazards, achieving a balance between engineering reliability and economy.