Industrial pipelines are the lifeblood of chemical, thermal, water supply, oil and gas, pharmaceutical and other facilities. Valves, as the core of pipeline control, perform functions such as cutting off, regulating, reversing, reducing pressure, safely releasing pressure, draining water and condensate. Incorrect selection can lead to medium leakage, pressure， soaring energy consumption， equipment damage， and even safety accidents. This article systematically analyzes eight common industrial valves： ball valve， gate valve， globe valve， butterfly valve， check valve， pressure reducing valve， safety valve， and steam trap. It explains the structural characteristics， advantages and disadvantages， applicable conditions， selection points， and pre-filtering matching schemes to provide reference for engineering design， on-site renovation， and equipment operation and maintenance.

1. Core Technologies of Eight Industrial Valves

1. Ball Valve

Structural Principle： The ball with a through-hole rotates 90° to achieve on-off， divided into floating ball and fixed ball， capable of reversing (three-way / four-way ball valve).

Advantages： Quick opening and closing， low flow resistance， excellent sealing performance， suitable for high-pressure and low-temperature conditions， some structures can withstand particle media.

Disadvantages： Ordinary soft-sealed ball valves have limited high-temperature resistance； not suitable for long-term small opening throttling， the semi-open state is prone to erosion and damage to the sealing surface.

Applicable Scenarios： Oil products， gas， process water， corrosive medium pipelines； mostly used for rapid cutting and medium switching； fixed ball valve is mostly used in high-pressure large-diameter conditions.

Filtering Equipment Matching： Clean medium can be selected as needed； for media with particles， a basket-type filter should be configured upstream； new pipelines must be flushed before commissioning.

2. Gate Valve

Structural Principle： The gate plate rises and falls vertically to achieve on-off， only suitable for full opening and full closing， does not allow throttling operation.

Advantages： The flow resistance in the fully open state is extremely low， the medium can flow in both directions， the valve body structure length is short.

Disadvantages： The opening and closing stroke is long， the opening and closing speed is slow； the semi-open gate plate is prone to erosion and damage to the sealing surface， not suitable for frequent operation.

Applicable Scenarios： Steam， water supply， oil pipelines， as a long-term maintained fully open or fully closed isolation valve.

Filtering Equipment Matching： For media with a lot of impurities， a Y-type filter with 20-30 mesh should be configured upstream； for clean medium， it can be omitted.

3. Globe Valve

Structural Principle： The valve disc rises and falls along the axis of the valve seat to press the valve seat and complete sealing， capable of cutting off or throttling.

Advantages： Reliable cutting-off， excellent flow regulation performance， convenient maintenance， good stability in high-temperature and high-pressure conditions.

Disadvantages： High pipeline flow resistance， single-directional flow of the medium， large opening torque.

Applicable Scenarios： Steam， water， oil systems， as a pipeline for long-term maintaining full open or full closed， commonly used as isolation valves in steam systems.

Filtering Equipment Matching： For impure media environments， a Y-type filter should be configured upstream to prevent particle scratches on the valve seat sealing surface.

4. Butterfly Valve

Structural Principle： The round disc butterfly plate rotates 90° to complete the switch and flow regulation.

Advantages： Small volume， light weight， small installation space occupation， quick opening and closing， low cost， outstanding performance in high-pressure and large-diameter pipelines.

Disadvantages： Medium sealing performance is average， pressure-bearing capacity is limited， restricted in high-temperature conditions.

Applicable Scenarios： Water supply， smoke and air ventilation， general process fluids， low-pressure and medium-diameter pipelines for cutting and regulation.

Filtering Equipment Matching： For media with a lot of impurities， a pre-filter should be configured upstream to avoid particle blockage of the butterfly plate.

5. Check Valve

Structural Principle： It automatically opens and closes based on the medium pressure to achieve one-way flow， divided into swing type， lift type， and butterfly type， preventing backflow of the medium.

Advantages： No manual operation required， protects pumps， heat exchangers， etc. from backflow impact.

Disadvantages： Likely to cause water hammer effect； the lift type check valve is sensitive to flow resistance.

Applicable Scenarios： At the pump outlet， after the heat exchange equipment， to prevent backflow of the medium.

Filtering Equipment Matching： For lift-type check valves， it is recommended to add a filter upstream； the anti-impurity ability of the swing type is stronger， and it can be appropriately selected.

6. Pressure Reducing Valve

Structural principle: The throttling element automatically dissipates pressure and stabilizes the downstream output pressure. It is divided into membrane type and piston type.

Advantages: Automatic pressure stabilization, downstream pressure is not affected by fluctuations in upstream pressure and flow.

Disadvantages: The flow channel gap is precise, and impurities are prone to causing blockage and failure; it cannot be used as a shut-off valve.

Applicable scenarios: Steam, compressed air, and process water systems, reducing high-pressure media to the required working pressure for the process.

Filtering equipment matching [must be equipped]: Install a Y-type filter with 30-40 mesh upstream; set a shut-off valve before and after the filter to facilitate cleaning and maintenance without stopping the machine.

7. Safety Valve

Structural principle: Spring/weight-driven, automatically activates to relieve pressure when the system exceeds pressure, and returns to the seat when the pressure drops. It belongs to a mandatory safety accessory.

Advantages: Passive safety protection, avoiding pipeline and pressure vessel overpressure accidents.

Disadvantages: Only activates in overpressure conditions; requires regular calibration of the set pressure.

Applicable scenarios: Overpressure protection for pressure vessels and pressure pipelines.

Filtering equipment matching [special requirements]: Do not use fine filters; only configure 10-20 mesh coarse filters to block large weld slag; prefer overall pipeline blowdown, and cannot rely on the filter for main protection.

8. Condensate Valve

Structural principle: Operates automatically based on changes in medium temperature and density, discharging condensate and retaining steam, divided into float ball type, thermal power type, and thermal static type.

Advantages: Fully automatic operation, discharging condensate, saving steam energy consumption.

Disadvantages: Scale and weld slag are prone to blocking internal components, resulting in no drainage or steam leakage failure, requiring regular maintenance.

Applicable scenarios: Steam heating, heat exchangers, steam pipelines, discharging condensate.

Filtering equipment matching [must be equipped]: Standardly install a Y-type filter with 20-40 mesh upstream; the filter's discharge port is downward, and a shut-off valve is provided to facilitate maintenance.

II. Quick Selection Guide for Design

1. Only need to cut off the pipeline: High-pressure select ball valve or gate valve; large-diameter low-pressure prefer butterfly valve; frequent opening and closing prefer ball valve.

2. Need flow throttling regulation: Prefer stop valve or butterfly valve; ball valve is prohibited from being in a semi-open state for long-term throttling.

3. Prevent reverse flow of medium: Select check valve; assess the risk of water hammer during the design stage.

4. Classic combination for steam systems: Stop valve (separation) + Y-type filter + pressure reducing valve + equipment + Y-type filter + condensate valve + check valve, with safety valve as overpressure safety protection.

5. Precise valve components remember pre-filtering: Pressure reducing valve, condensate valve filter are mandatory; stop valve is selected based on the cleanliness of the medium; safety valve must not be protected by fine filters.

III. General Design Points for Filter-Valve Matching

1. Filters are uniformly installed upstream of the valve, with the medium filtered first before entering the valve component, and no protection effect is provided downstream.

2. For key continuous operation circuits, set shut-off valves before and after the filter + bypass pipeline; cleaning the filter screen does not require system shutdown.

3. Y-type filters are installed diagonally downward to facilitate sediment collection and impurity collection, and the cavity must not face upward.

4. Before the new pipeline is put into operation, remove the filter screen, blow the pipeline first to remove weld slag and rust, and then install the filter screen.

5. Important pipelines can be equipped with pressure difference meters; an increase in pressure difference indicates filter blockage, and timely cleaning and replacement are required.

6. Filters cannot replace pipeline blowdown; they are only used as a protective measure for valves and require regular cleaning and maintenance.

IV. Frequent Pitfalls in the Field

- Omitting the pre-filter of pressure reducing valve and condensate valve, causing frequent failures and leakage of the valve components;

- Installing fine filters on safety valves, blocking the discharge channel, and posing a major safety hazard;

- Installing Y-type filters in reverse or upward, completely losing the function of collecting and filtering impurities;

- Keeping the ball valve in a small opening state for long-term throttling, causing rapid wear and failure.