API 602 is a standard developed by the American Petroleum Institute (API) that specifies the requirements for compact forged steel gate valves, globe valves, check valves, and filters. It covers small-bore sizes with a maximum nominal diameter of NPS 4 (DN 100) and pressure ratings up to 2500 or 4500, depending on the design scope.

Valve Types: Gate valves, globe valves, check valves, and filters;

Size Range: 1/4'' ~ 2'' (DN8 ~ DN50);

Pressure Ratings: ANSI Class 150, ANSI Class 300, ANSI Class 600, ANSI Class 800, ANSI Class 1500, and ANSI Class 2500;

Valve Body Construction: Forged steel valve body, such as A105, F304, etc., with high pressure and high temperature toughness;

End Connections: Threaded connection, socket weld connection, flange connection, or butt weld connection.

Face-to-Face: Shorter structural length and smaller overall size compared to heavy-duty cast valves such as API 600;

Bonnet Options: Bolted Bonnet, Welded Bonnet, Pressure Sealing Bonnet, designed to prevent leakage under stringent operating stresses;

Emissions Compliance: Typically designed to meet fugitive emission requirements such as API 624 or ISO 15848-1.

1. Main Features of Y-Type Strainer:

Extremely low flow resistance, compact structure, and easy maintenance;

2.11 Advantages of Y-Type Strainers:

① Small size and flexible installation; can be installed horizontally or vertically, even in narrow pipe locations;

② Simple structure, low cost, easy disassembly and maintenance, and convenient drainage;

③ Moderate flow resistance, low pressure loss for conventional clean media;

④ Wide pressure rating coverage, with corresponding specifications for normal pressure, medium-pressure, and high-pressure operating conditions.

2.12 Disadvantages of Y-Type Strainers:

① Very small impurity capacity of the filter screen, easily clogged, unsuitable for media with high impurity content;

② Poor manufacturing economy for large-diameter specifications; rarely used for sizes above DN200;

③ Filter screen subjected to oblique force; prone to deformation and damage under high pressure and high flow conditions;

④ High maintenance workload under frequent drainage conditions.

2.13 Main Application Areas of Y-Type Strainers:

① Water supply and drainage, HVAC circulating water, gas pipelines, compressed air pipelines;

② Small protective filters before valves and pumps (stop valves, solenoid valves, pre-protection for small water pumps);

③ Clean oil products in petroleum refining, steam pipelines, heat transfer oil pipelines;

④ Clean process media in chemical industry, fire protection pipelines, central air conditioning systems;

⑤ Pipe diameter range: DN15~DN200.

3. Selection Recommendations:

3.1 For small-diameter pipes, clean media, and protective valves/pumps, a Y-type Strainer is recommended.

3.2 For small-diameter instrument pressure lines, a Y-type Strainer is recommended.

3.3 For steam systems with small pipe diameters, a Y-type Strainer is recommended.