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Hydrotherms simplex basket strainer — product photograph
Hydrotherms

Simplex Basket Strainer

High-capacity basket filtration for continuous liquid service across a wide range of industries and pressures.

Size
0.5″ – 78″+
Pressure
Class 2500lb+
Ends
FLG · BW
78″+
Maximum Size
2500lb+
Max Pressure Class
600lb
Cast Max Class
400
Finest Mesh
Basket Filtration

Overview

A basket strainer is a closed vessel with a cleanable screen element designed to remove and retain foreign particles down to 0.0254mm from variable flowing fluids. The basket-type strainer is characterised by a vertically oriented chamber, typically larger than that of a Y-type strainer. It has a greater free straining area, resulting in less pressure drop than the Y-type strainer, making it the preferred choice for liquid applications.

The basket-type strainer is also used on larger-diameter steam pipelines due to its greater dirt-holding capacity. Hydrotherms manufacture basket strainers with a free-straining area a minimum of six times the cross-sectional pipe area. Basket seats are precision machined to give a tight seal and prevent any material from bypassing the basket.

Specifications

Size & Range

Cast Basket Strainers / Simplex Strainers
  • Sizes from 0.5″ (15mm) to 36″+ (900mm+)
  • Maximum pressure ratings ANSI Class 600lb
  • Flanged ends ANSI, BS4504, DIN, BS10, and BW ends from Sched 40 to Sch 100 + Special Schedule
Fabricated Basket / Simplex Strainers
  • Sizes from 0.5″ (15mm) to 78″+ (1980mm+)
  • Maximum pressure rating Class 2500lb+ (172 BarG+)
  • Flanged ends ANSI, BS4504, DIN, BS10, and BW ends from Sched 40 to Sch 100 + Special Schedule
  • Flanged End Strainers: BS10, BS4504, ANSI B16.5, ANSI B16.47 Series A (MSS SP 44), ANSI B16.47 Series B (API 605), AWWA C207 Class D & E, ASME, EN1092, DIN, NFE, JIS, and ISO Standards
  • Buttweld End Strainers in accordance with ANSI B16.25

Consult Hydrotherms for other End Connections and Standards

Engineering

Features

Single-piece cast construction with integral flanges
Fabricated Heavy-Duty Construction
Large capacity baskets
Low-pressure loss
End connections flanged, butt welded, and socket welded
Welding carried out to ASME IX
NDE carried out to code requirements
Standard stainless-steel screens
Configure

Options

Access & Closure

  • Quick open cover / closure
  • Hinged cover or davit assembly for easier maintenance

Screen & Basket

  • Multiple basket filters for large straining areas
  • Pleated Baskets for higher Open Area Ratios
  • Wedge Wire screens
  • Perforated stainless steel screens — 1/32″ to ½″
  • 20, 40, 60, 80, 100, 150, 200, 325, and 400 mesh stainless steel screens
  • Backflush, backwash, and blow down

Instrumentation & Valves

  • Pressure differential gauge and switches
  • Air Eliminator or air vent valve
  • Vent valves and drain valves

Construction & Finish

  • High-pressure capabilities
  • Steam jacket for highly viscous fluids
  • Rotated or offset nozzle placement
  • Special external / internal coatings upon request
  • Zinc anodes for saltwater service
  • Support legs and skid mounted
  • "U" stamp certification
Quality Assurance

Certifications

Material certification to EN 10204, with NACE MR0175 / ISO 15156 compliance for sour service, and a full suite of additional testing available on request.

CertificationService Condition
Standard service

Supplied as standard on all Hydrotherms strainers. Certifies that pressure-wetted components meet the specified material standard, validated by the manufacturer's authorised inspection representative independent of the manufacturing department.

Critical service

For applications demanding the highest level of assurance, certification is countersigned by an independent third-party inspector or the customer's authorised representative, providing an additional layer of verification.

Sour service — H₂S present

Where hydrogen sulfide is present, materials comply fully with NACE MR0175 / ISO 15156 — governing hardness limits, heat treatment and alloy composition across every pressure-wetted component: body, cover, screen, bolting and sealing elements. Eliminates the risk of sulphide stress cracking (SSC), hydrogen induced cracking (HIC) and SOHIC.

Sour · critical · offshore

The most demanding sour-service specification: independent third-party verification combined with full NACE compliance, for offshore, regulated upstream oil & gas, sour gas processing, amine treating and LNG applications.

Additional Testing & Certificates

Beyond the standard hydrostatic test, Hydrotherms can perform the following examinations and supply the corresponding certificates on request. Select a test to read its scope.

Every Hydrotherms strainer is hydrostatically tested to 1.5 times the maximum allowable working pressure (MAWP) prior to despatch, in accordance with ASME Section VIII requirements. Shell integrity, joint tightness, and cover seal performance are verified under sustained test pressure. A formal hydrostatic test certificate — recording test medium, test pressure, hold duration, and witnessed result — is issued as a standard deliverable with every order, with no exceptions.

Performed using compressed air or inert gas (typically nitrogen) in lieu of hydrostatic testing, where water contact is undesirable or impractical. Used to verify pressure integrity and leak-tightness. Conducted at agreed test pressures per applicable code requirements, with all safety precautions for pneumatic testing in place.

Measures the differential pressure loss across the strainer at specified flow rates and fluid conditions. Results confirm that the strainer meets the pressure drop requirements of the system design and provides a baseline for future fouling monitoring in service.

The most sensitive leak detection method available. Helium is used as a tracer gas and detected by a mass spectrometer leak detector, capable of identifying leakage rates as low as 1×10⁻⁹ mbar·l/s. Specified for critical applications including cryogenic, toxic fluid, high-vacuum, and semiconductor services.

The strainer is pressurised to destruction to determine its actual burst pressure and failure mode. Confirms that the design safety margin exceeds the minimum required factor and validates finite element analysis (FEA) predictions. Typically performed on prototype or first-article samples.

Simulates pressure surge (water hammer) conditions to verify that the strainer body, cover, and screen withstand transient peak pressure events without deformation or leakage. Critical for pump discharge and fast-acting valve installations.

X-ray or gamma-ray examination of welds and castings to detect internal discontinuities including porosity, slag inclusions, lack of fusion, and cracks — defects that are invisible to surface examination. Conducted and reported in accordance with ASME Section V and the applicable acceptance criteria of ASME Section VIII.

Detects surface and near-surface discontinuities in ferromagnetic materials by applying magnetic flux and iron particle media. Reveals cracks, laps, seams, and inclusions that could compromise the integrity of weld joints or base material. Performed to ASME Section V, Article 7.

A liquid penetrant is applied to the cleaned surface, drawn into surface-breaking defects by capillary action, and subsequently revealed by a developer. Applicable to all non-porous materials including stainless steel, duplex, and nickel alloys where magnetic particle testing is not feasible. Performed to ASME Section V, Article 6.

High-frequency sound waves are used to detect internal and surface flaws in welds and base material, and to measure wall thickness. Particularly effective for detecting planar defects such as lack of fusion and cracks. Also used for thickness measurement on castings and formed components where dimensional access is restricted.

A chemical surface test used to detect free iron contamination on stainless steel components. A ferroxyl reagent solution is applied to the surface; any free iron deposits turn blue, confirming the presence of contamination that could initiate corrosion in service. Mandatory for many food, pharmaceutical, and high-purity stainless steel applications.

Tensile test specimens are machined from the same heat of material as the strainer components and tested to determine yield strength, ultimate tensile strength, and elongation. Results confirm that the material meets the minimum mechanical property requirements of the specified material standard and design code.

Brinell, Rockwell, or Vickers hardness measurements are taken on base material, weld metal, and heat-affected zones. Hardness testing is mandatory for all NACE MR0175 / ISO 15156 applications to confirm that material hardness does not exceed the limits above which sulphide stress cracking can occur. Also used to verify post-weld heat treatment (PWHT) effectiveness.

Charpy V-notch impact tests are performed at the minimum design temperature (MDT) to verify that materials possess adequate notch toughness and resistance to brittle fracture. Required by ASME Section VIII for low-temperature carbon steel (LTCS) applications and for all materials used below −29°C. Results must meet the minimum absorbed energy values specified by the design code.

Electrical resistance strain gauges are bonded to the strainer body at critical stress locations. Actual surface strains are measured under defined pressure and load conditions and compared against design predictions. Used to validate FEA models and confirm structural adequacy for non-standard geometries or extreme service conditions.

A brittle lacquer coating is applied to the component surface. Under applied load, the coating cracks at yield locations, visually mapping the strain distribution and identifying stress concentration areas. Provides a full-field indication of stress patterns that complements strain-gauge point measurements.

Pressure and leak testing performed at cryogenic temperatures — typically down to −196°C for LNG and liquid nitrogen service. Confirms that all materials, welds, seals, and fasteners maintain their mechanical properties and leak-tight integrity at the extreme low temperatures encountered in LNG, cryogenic processing, and cold box applications.

Evaluates structural integrity under sudden mechanical shock loads — including those resulting from water hammer, seismic events, or transportation impacts. Required for naval, offshore, and seismically active installation sites.

Subjects the strainer to defined vibration profiles to verify that connections, fasteners, and screen elements remain secure under continuous operational vibration. Particularly relevant for strainers installed on or near rotating equipment such as pumps, compressors, and turbines.

Functional operation tests to verify that all moving components — including covers, quick-opening closures, diverter valves (duplex strainers), and access flanges — operate correctly, smoothly, and within the required torque or force limits. Confirms ease of maintenance and correct mechanical assembly prior to despatch.

Tensile or bent-beam specimens are exposed to a defined H₂S-saturated test solution at controlled stress levels to evaluate susceptibility to sulphide stress cracking (SSC) — a form of hydrogen embrittlement that affects high-strength steels in sour environments. Performed in accordance with NACE TM0177 methods. Required on critical sour service components to provide independent confirmation of SSC resistance beyond hardness compliance alone.

Plate specimens are immersed in a standard H₂S test solution per NACE TM0284 to evaluate susceptibility to hydrogen induced cracking (HIC) — step-wise cracking caused by hydrogen diffusion into the steel microstructure. Crack length ratio (CLR), crack thickness ratio (CTR), and crack sensitivity ratio (CSR) are measured and reported. Required for carbon steel pressure vessels and piping components in wet sour service per NACE MR0175 / ISO 15156.

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Answers

Frequently Asked Questions

A simplex basket strainer is a single-chamber filtration vessel designed to remove solid particles down to 0.0254mm from flowing process fluids. It features a vertically-oriented basket with a large free-straining area — a minimum of six times the cross-sectional pipe area in Hydrotherms designs — resulting in low pressure drop and high dirt-holding capacity. It is the preferred strainer type for liquid applications.

A basket strainer is preferred when the process fluid is liquid, the line carries higher solids loading, or a lower pressure drop is critical. Basket strainers have significantly greater dirt-holding capacity than Y strainers and are available in much larger sizes — up to 78″+ in fabricated construction. For gas and steam service in smaller bore lines, a Y strainer is typically more suitable.

Hydrotherms simplex basket strainers are available from 0.5″ (15mm) to 36″+ (900mm+) in cast construction with maximum pressure ratings of ANSI Class 600lb. Fabricated basket strainers are available from 0.5″ (15mm) to 78″+ (1980mm+) with maximum pressure ratings of Class 2500lb+ (172 BarG+).

Hydrotherms basket strainers are available with perforated stainless steel screens from 1/32" to ½", and wire mesh screens in 20, 40, 60, 80, 100, 150, 200, 325, and 400 mesh grades. Pleated baskets for higher open area ratios and wedge wire screens are also available. Screen selection depends on the particle size to be retained and the process fluid viscosity.

Yes. Hydrotherms fabricated basket strainers are available up to Class 2500lb+ (172 BarG+) for high-pressure applications. Options include high-pressure quick-opening closures, davit assemblies, and pressure differential gauges and switches. All high-pressure units are designed to ASME Section VIII and hydrostatically tested at 1.5× MAWP prior to despatch.

Hydrotherms basket strainers are available with EN 10204 Type 3.1 (standard) or Type 3.2 (independent third-party verification) material certification. For sour service, NACE MR0175/ISO 15156 compliance is available in combination with either Type 3.1 or 3.2. All units are supplied with hydrostatic test certificates as standard. ASME 'U' stamp certification is also available.