Deflagration Flame Arrester
Product Model: ZD-FA13 (Pre-Volume / Chamber Protected)
Type: End-of-Line or In-Line Deflagration Arrester with Integrated Expansion Chamber
Material: Housing: Carbon Steel or Stainless Steel. Includes an enlarged chamber upstream of the element.
Key Feature: An integral pre-volume chamber protects the flame arrest element from direct exposure to liquid slugs, corrosion from wet vapors, and damage from pipe debris.
Principle: The chamber allows for velocity reduction, liquid dropout, and pressure wave dampening before gases reach the sensitive element.
Typical Use: Tank vents with potential for liquid overflow or carryover, vent lines from processes with erratic or "dirty" gas streams, and as a general reliability upgrade for critical vent points.
Overview
In many vent applications, the flame arrest element is mounted directly in the pipe, making it vulnerable. The Pre-Volume Protected Flame Arrester adds a simple yet highly effective layer of defense: an engineered expansion chamber upstream of the element. This chamber serves multiple protective functions: it acts as a mini knock-out pot for liquid slugs, allows particulates to fall out, reduces gas velocity (and thus erosive potential), and can help dampen pressure fluctuations. This design significantly enhances the reliability and longevity of the flame arrest element, especially in challenging or less predictable services.
Features & Benefits
Element Protection: Shields the critical quenching matrix from direct impact by liquids, ice, hydrate chunks, or pipeline scale.
Improved Performance: By providing a calmer, drier, and cleaner gas stream to the element, its flame quenching efficiency is maintained, and pressure drop remains stable.
Reduces Plugging Risk: Allows for separation of entrained liquids and solids that could otherwise rapidly foul a standard in-pipe element.
Versatile & Robust: A practical solution for upgrading protection on existing vents or specifying for new installations where stream conditions may vary.
How It Works
The process vapor enters the enlarged pre-chamber. Here, the flow velocity drops dramatically. Due to gravity, any liquid droplets or heavy particulates fall to the bottom of the chamber (which may include a drain). The vapor then turns and passes through the flame arrest element, which is mounted at the outlet of the chamber. The chamber volume also provides a buffer that can absorb minor pressure spikes without stressing the element.
Specifications (Descriptive)
The unit is characterized by its pre-chamber volume, which is sized based on pipe size and potential liquid load (e.g., 10-20 times the pipe volume). Standard pipe connections range from DN50 to DN200. The overall device is larger and heavier than a standard in-line arrester. The chamber includes a drain connection (½” or ¾” NPT). The integrated flame arrest element is a standard certified type. Materials match the process requirements (CS, SS).
Q&A
Q: Is this a substitute for a proper knock-out drum?
A: No. It is a supplemental protective device. For streams with known, significant liquid loads, a primary liquid separator (knock-out drum) must be installed upstream. This unit provides secondary protection and guards against unexpected upsets or minor carryover.
Q: How do you maintain it?
A: Maintenance involves periodically draining any accumulated liquid from the chamber sump and inspecting/cleaning the flame arrest element. The frequency depends on the service. The chamber design makes visual inspection of the inlet side of the element easier.
Q: Can it be used in freezing climates?
A: If the liquid being drained can freeze, the chamber and drain line require insulation and heat tracing to remain functional. Otherwise, ice can block the chamber.
Q: Does the pre-volume affect its flame arrest certification?
A: The device is tested and certified as a complete assembly (chamber + element). The chamber is part of the certified design. It does not negatively affect performance; in some cases, it may improve it by conditioning the flow.
About ZD Safety
We focus on durability and reliability. The pre-volume protected arrester is a testament to practical engineering, adding a straightforward but highly effective feature that dramatically increases the operational robustness of a critical safety device in demanding service.
