A witches hat strainer (also known as a cone strainer or temporary cone filter) is a conical filtration device installed in pipelines to remove debris and protect downstream equipment. It is widely used during system startup, commissioning, and temporary filtration operations in industrial systems.
A witches hat strainer (also known as a cone strainer or temporary cone filter) is a conical filtration device installed in pipelines to remove debris and protect downstream equipment. It is widely used during system startup, commissioning, and temporary filtration operations in industrial systems.
Table of Contents
A witches hat strainer is a temporary pipeline filter shaped like a cone, designed to trap solid particles such as weld slag, rust, and debris during system startup.
Key Features:
• Conical shape for efficient flow distribution
• High dirt-holding capacity
• Low pressure drop
• Easy installation and removal
In-depth Reading → What Is a Witches Hat Strainer?
The working principle is simple but highly effective:
• Fluid enters the pipeline
• Flow passes through the cone-shaped filter
• Solid particles are trapped inside or on the surface
• Clean fluid continues downstream
Engineering Insight:
The conical geometry increases filtration surface area
Reduces turbulence and pressure loss
Improves debris retention during high-flow startup conditions
1. Wire Mesh Cone Strainer
Fine filtration (20–200 mesh)
Ideal for small particles
2. Perforated Cone Strainer
Larger holes (1mm–10mm)
Used for coarse filtration
3. Hybrid Type (Mesh + Perforated)
Combines strength and precision
Most commonly used in industrial pipelines
Related Reading → Wire Mesh and Perforated Temporary Filter
Correct installation is critical for performance.
Flow Direction Types:
| Type | Description | Use Case |
|---|---|---|
| Cone Pointing Upstream | Fluid hits outside first | High debris systems |
| Cone Pointing Downstream | Fluid flows inside first | Lower pressure drop |
Best Practice:
Install with the cone tip facing upstream for maximum debris capture
Ensure proper sealing to avoid bypass
In-depth Reading → Witches Hat Strainer Flow Direction
Witches hat strainers are widely used in:
• Oil & Gas
• Pipeline commissioning
• Refinery startup
• Water Treatment
• Pre-filtration systems
• Pump protection
• Chemical Industry
• Process fluid filtration
• Equipment protection
• Industrial Systems
• Heat exchangers
• Valves & pumps
Application Case → Witches Hat Oilfield Strainer
| Feature | Witches Hat Strainer | Basket Strainer | Y-Strainer |
|---|---|---|---|
| Type | Temporary | Permanent | Permanent |
| Shape | Cone | Basket | Y-shape |
| Installation | Between flanges | Inline housing | Inline |
| Maintenance | Removed after use | Cleanable | Cleanable |
| Use Case | Startup filtration | Continuous use | Compact systems |
Related Reading → Temporary Strainer - Cone, Basket, Flat Type
• Materials:
Stainless Steel 304
Stainless Steel 316 or 316L
Duplex Stainless Steel
• Specifications:
Mesh: 20–200 mesh
Perforation: 1–10 mm
Open Area: up to 150% of pipe cross-section
Size Range: DN15 – DN1200
• Customization:
Handle design
Reinforcement rings
Special alloys
Choosing the right strainer depends on:
1. Particle Size
→ Determines mesh size
2. Flow Rate
→ Affects pressure drop
3. Pressure Conditions
→ Requires structural strength
4. Usage Duration
→ Temporary vs extended use
5. Fluid Type
→ Determines material selection
Selection Guide → Witches Hat Strainer Guideline
1. What is a witches hat strainer used for?
It is used for temporary filtration during pipeline startup to remove debris and protect equipment.
2. Is a cone strainer reusable?
Yes, depending on contamination level and material strength.
3. What is the correct flow direction?
Typically, the cone tip faces upstream for better debris capture.
4. What mesh size should I choose?
It depends on particle size and system requirements (commonly 20–200 mesh).
5. What is the difference between cone and basket strainers?
Cone strainers are temporary, while basket strainers are permanent filtration devices.
6. When should the strainer be removed?
After system startup or once debris levels stabilize.
Witches hat strainers are essential components in industrial filtration systems, especially during startup and commissioning phases. With their simple design, high efficiency, and cost-effectiveness, they provide reliable protection for pipelines and critical equipment.
For optimized performance, selecting the right type, material, and installation method is crucial.
