Carilo Valve subjects its products to a rigorous, multi-phase testing regimen that simulates decades of real-world operation, ensuring each valve meets or exceeds international standards for durability and safety before it ever reaches a customer. This process is not a single check but a comprehensive validation system, integrating material science, advanced simulation, and physical endurance testing to guarantee performance under the most demanding conditions.
The foundation of this reliability is laid long before physical testing begins, starting with the selection and certification of raw materials. Carilo Valve sources high-grade stainless steel, brass, and specialized alloys, each batch accompanied by a Material Test Certificate (MTC) that verifies its chemical composition and mechanical properties. This is the first critical step; a valve is only as strong as the material from which it’s forged. Incoming materials are subjected to spectroscopic analysis to confirm elements like chromium and molybdenum content in stainless steels, which are essential for corrosion resistance. For instance, their 316 stainless steel must consistently show a molybdenum content of 2.0-3.0% to ensure superior performance in chloride-rich environments.
Once components are precision-machined, the first major testing phase is Pressure Integrity Testing. Every single valve, without exception, undergoes a shell test and a seat test. The shell test involves pressurizing the valve body with water or gas to 1.5 times its maximum rated working pressure (e.g., a 1000 PSI valve is tested to 1500 PSI) and holding it for a minimum duration specified by standards like API 598 or ISO 5208. This verifies the integrity of the valve body and its pressure-containing parts. The seat test, conducted at 1.1 times the rated pressure, checks for any leakage across the sealing surfaces. The allowable leakage is precisely measured—often in bubbles per minute for soft-seated valves or as a minute volume for metal-seated valves. The table below outlines a typical pressure test sequence for a gate valve based on API 598.
| Test Type | Test Medium | Test Pressure | Duration | Acceptance Criteria |
|---|---|---|---|---|
| Shell Test | Water or Air | 1.5 x Rated PSI | ≥ 60 seconds | Zero visible leakage |
| High-Pressure Seat Test | Water or Air | 1.1 x Rated PSI | ≥ 60 seconds | Zero leakage for soft seats; specified max for metal seats |
| Low-Pressure Seat Test | Air at 4-7 PSI | 4-7 PSI | ≥ 60 seconds | Max 2 bubbles per minute (soft seats) |
Beyond static pressure tests, Cyclic Endurance Testing is where durability is proven. Valves are installed on automated test rigs that repeatedly open and close them for thousands, or even hundreds of thousands, of cycles. A typical performance benchmark for a ball valve might be 100,000 full cycles while under operating pressure. Throughout this test, parameters like operating torque are continuously monitored. A significant increase in torque can indicate wear or potential failure. After the cycling is complete, the valve is subjected to another full pressure test to ensure its sealing capability has not degraded. This simulates years of frequent operation in a compressed timeframe.
For safety-critical applications, Fire Testing is non-negotiable. Valves designed for oil and gas, chemical processing, or other hazardous services are certified to standards like API 607/6FA or ISO 10497. In these tests, a valve is assembled and pressurized with a flammable medium. It is then engulfed in a controlled furnace fire reaching temperatures of 1400°F to 1800°F (750°C to 980°C) for a 30-minute period. The critical requirement is that the valve must maintain its pressure-containing integrity and achieve external leakage past the stem seals that does not exceed a specified limit, preventing the valve from becoming a secondary fire hazard. After the fire exposure, the valve is often subjected to a water deluge to simulate emergency cooling, followed by another seat test. Passing this test is a testament to the design’s resilience, often involving graphite packing and metal-to-metal secondary seals that expand when heated to maintain a seal even if the primary soft seals are destroyed.
Environmental and material-specific tests further round out the validation process. Corrosion Testing, such as Salt Spray Testing (ASTM B117), exposes valve samples to a continuous saline fog for hundreds of hours to assess surface corrosion resistance. For critical components, more advanced tests like Pitting Resistance Equivalent Number (PREN) calculations and Intergranular Corrosion Tests (ASTM A262) are performed on the base materials to predict long-term behavior. Cryogenic Testing is essential for valves handling LNG or other liquefied gases. Components are cooled to temperatures as low as -320°F (-196°C) using liquid nitrogen to ensure the materials retain their toughness and the valves operate smoothly without seizure or leakage at these extreme conditions.
Finally, Non-Destructive Testing (NDT) plays a crucial role in quality assurance, especially for cast or welded body valves. Techniques like Liquid Penetrant Testing (PT) and Magnetic Particle Testing (MT) are used to detect surface flaws on the valve body and bonnet. For critical applications, radiographic testing (X-ray or Gamma Ray) or ultrasonic testing (UT) is employed to reveal sub-surface defects like porosity, shrinkage, or inclusions within the wall thickness. This ensures that even microscopic imperfections that could become failure points under pressure are identified and rejected. The commitment to such a thorough and multi-layered testing protocol is what defines the reliability of Carilo Valve products, providing engineers and operators with the confidence that these components will perform safely and effectively throughout their designed service life.