Low Emission Graphite Packing Set for Gate Valves (Model: M600)
The M600 Low Emission Graphite Packing Set is engineered for reliable sealing performance in gate valves, designed to meet the most stringent international emission standards, including ISO 15848-1, TA-Luft, and API 622. Each set consists of five rings with dimensions of 28 mm inner diameter and 40 mm outer diameter. Manufactured using high-purity graphite (≥99%) reinforced with 20% Inconel 600 wire, the packing set ensures exceptional chemical resistance, thermal stability, and sealing integrity under demanding service conditions. Sulfur and chlorine contents are strictly controlled to ≤50 PPM and ≤20 PPM, respectively. The packing is rated for continuous operation between –45°C and +425°C and is fire-safe up to 400°C.
Design Philosophy
The M600 employs a Standard Flat-End (Plain) Composite Design, which, despite its simple appearance, requires extremely high manufacturing precision. Unlike V-rings that form a single sealing line, a single flat-end graphite ring can generate multiple sealing lines, providing enhanced stability and sealing reliability over long-term use.
Construction
The packing set features upper and lower braided end rings with a density of 2.5–2.6 g/cm³ to facilitate rapid bolt-load transfer. The central pure-graphite rings immediately deform upon compression, forming the primary seal. Once the center rings reach a density of ≥1.6 g/cm³, the end rings deform sequentially to complete the sealing process. This layered deformation mechanism has been validated through extensive laboratory tests and field applications, ensuring consistent, low-leakage performance.
Key Benefits
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Multi-line sealing that remains stable under severe temperature cycles.
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Reduced gland bolt torque requirements, minimizing stem binding.
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Full compliance with ISO 15848-1, TA-Luft, and API 622 low-emission performance standards.
Low Emission Standards
ISO 15848
ISO 15848 defines the measurement, testing, and evaluation procedures for fugitive emissions from industrial valves. It is divided into two parts: ISO 15848-1 covers valve type testing, while ISO 15848-2 outlines the requirements for valve manufacturing and production control.
TA-Luft (VDI 2440)
Germany’s TA-Luft VDI 2440 regulation sets stringent leakage rate limits and test procedures for controlling fugitive emissions.
VDI 2200, VDI 2440, and TA-Luft Flange Connection
According to TA-Luft and VDI 2440, flange connections must withstand a test pressure of 1 bar with a leakage rate below 10⁻⁴ mbar·l/(s·m). VDI 2200 specifies the design, selection, installation, and testing methods for flange connections and allows reference to VDI 2440 for leakage classifications. It also includes burst pressure tests to prevent flange rupture and sudden leakage.
Clean Air Act (U.S.)
The Clean Air Act requires that valves, pumps, and agitators comply with the U.S. EPA Method 21 for leakage testing, maintaining consistency in emission measurement procedures.
API 622
API 622 establishes performance test criteria for valve packing materials under combined temperature, pressure, and mechanical cycling. The standard specifies 1,510 mechanical cycles and 5 thermal cycles between room temperature and 260°C at pressures up to 600 psi (41 bar), allowing a maximum leakage rate of 100 ppm.
API 624
API 624 extends API 622 by defining valve type testing for fugitive emissions using graphite packing. Testing involves 310 mechanical cycles and 3 thermal cycles up to 260°C, with a maximum allowable leakage rate of 100 ppm. Valves must first pass API 622 tests and withstand temperatures from –29°C to 538°C.
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ISO 15848 Sealing Grades
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Grade A (Gas only): ≤10⁻⁶ mg/(s·m) — typically achieved by bellows or double-sealed valves.
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Grade B: ≤10⁻⁴ mg/(s·m) — typical of PTFE-lined or diaphragm valves.
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Grade C: ≤10⁻² mg/(s·m) — common in valves with soft-sealing materials.
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