Industrial Fluid Handling

No. Flanges of the same nominal size under ASME B16.5, EN 1092-1, and JIS B2220 have different bolt hole counts, bolt circle diameters, and sealing face dimensions, making them incompatible. While nominal sizes may seem comparable and some ratings align (e.g., JIS 10K with ASME Class 150 and JIS 20K with Class 300), this does not ensure dimensional compatibility. Connections between systems require an adapter flange, spool piece, or a specially manufactured component, which should be addressed during the design stage.

No. The class designation is a dimensionless number, not a working pressure, and a Class 600 flange is not limited to 600 psi. Allowable pressure is determined by class, material group, and operating temperature together, read from pressure-temperature tables in the governing standard. Capacity falls as temperature rises, sometimes substantially, so a component adequate at ambient conditions can be inadequate in hot service. Select against design pressure and design temperature rather than against the class number.

Net positive suction head is the margin between the pressure available at a pump's suction and the vapor pressure of the fluid. NPSH available is a property of your system, determined by source pressure, elevation, temperature, and suction line losses. NPSH required is a property of the pump. If available does not exceed required with margin, the fluid vaporizes at the impeller inlet and the bubbles collapse violently, which is cavitation. It produces noise, vibration, and rapid impeller damage. It is the most common cause of pumps that meet their duty point on paper and fail in service, and it is checked separately from flow and head.

It depends on the fluid and what you need the flow to do. Centrifugal pumps use a rotating impeller and suit relatively low viscosity fluids at steady flow, with output that changes as system resistance changes. Positive displacement pumps move a fixed volume per cycle and deliver near constant flow regardless of pressure, which makes them the choice for viscous, shear-sensitive, or metered applications. That characteristic has a consequence: because a positive displacement pump will keep displacing against a closed discharge, overpressure protection is required rather than optional. Give a supplier the fluid, its viscosity at operating temperature, the flow required, and whether flow must stay constant.

Match the type to the duty. Ball and gate valves are for on and off service, opening fully with low pressure drop, and neither should be held partially open to regulate flow because the seat will be damaged. Globe valves are designed for throttling, at the cost of higher pressure drop. Butterfly valves are compact and economical in larger sizes and can isolate or throttle, though the disc stays in the flow when open. Check valves operate automatically to prevent reverse flow. Where flow must be modulated continuously against a control signal, that is a control valve, which is specified with its actuator and positioner as a package rather than as a valve alone.

The lower of the hose rating and the fitting rating. This is the point most often missed: a high-pressure hose fitted with a lower-rated coupling is rated at the coupling, not at the hose. Working pressure is the operating limit; burst pressure is a test figure and never a design basis. Two other practical points matter as much. Routing a hose inside its minimum bend radius shortens life substantially, and quick disconnect coupling profiles are largely proprietary between manufacturers, so interchangeability should be confirmed rather than assumed. Note also that hydraulic hose standards carry no approval list or certification body, so conformance claims come from the manufacturer.

On its own, very little. A micron rating states a particle size but not what proportion of particles at that size the element actually captures, which means two filters with the same stated rating can perform very differently. The meaningful figure is a beta ratio at a stated particle size, determined by multi-pass testing under a recognized method that measures particulate removal, contaminant capacity, and differential pressure characteristics together. When comparing elements, ask for the beta ratio, the particle size it was measured at, and the test standard followed. In service, change-out should be triggered by differential pressure rather than by elapsed time.

The applicable code depends on the service and industry, impacting wall thickness. ASME B31.1 governs power generation and related systems, focusing on steam, water cycles, and boiler piping. In contrast, ASME B31.3 covers process industries like refineries and pharmaceuticals. B31.1 typically allows for more conservative stress limits, leading to thicker walls and different pipe schedules. For gas distribution and pipeline transport, other B31 sections apply. Always confirm the governing code with the engineer of record.

Specify materials by ASTM designation instead of common names, as terms like "stainless steel" encompass various grades with differing properties. Clearly identify body, trim, seat, and elastomer materials, as softer components often set limits. Provide the supplier with fluid type, concentration, operating and upset temperatures, and any abrasive materials. For corrosive, unusual, or safety-critical services, material selection should be guided by engineering rather than purchasing.

Decide before manufacture, as many aspects cannot be added later. Material test reports link components to certifications, while pressure test certificates document shell and seat testing. For pumps, consider performance test data and acceptance grades for comparison. Service requirements include fire safe testing for hydrocarbons, fugitive emissions qualification to limit leakage, and approvals for potable water and food systems. Address all these factors during the quoting stage, as documentation affects supplier pricing.