What Are You Looking For?
Super Mini Metal Flat Ring Metal Super Mini Ring Metal Flat Ring Tower Packing Metal Flat Ring Rando Packing Metal Paul Ring Packing Metal raschig ring tower packing

English English

Projects

What's function of the plastic VSP ring?

Home Projects

What's function of the plastic VSP ring?

What's function of the plastic VSP ring?
December 13, 2025

 

 

Engineer's Brief: The plastic VSP ring (also called inner arc ring) is a high-performance random packing featuring evenly folded inner arcs along the axial direction, alternately arranged. Its primary function is to promote uniform gas-liquid distribution, reduce channeling and wall flow, and improve mass transfer efficiency in absorption, desulfurization, and decarbonization towers. Made in PP, PE, PVC, CPVC, or PVDF, it delivers 20–30% better distribution uniformity than standard Pall rings in corrosive services where metal packings would fail.

1. What Is the Plastic VSP Ring (Inner Arc Ring)?

Bulk plastic VSP ring inner arc packing in white PP and beige PE showing alternating arc structure

Figure 1: Plastic VSP Ring (Inner Arc Ring) — bulk PP and PE rings showing the characteristic alternating inner arcs and axial symmetry.

Unlike a smooth-walled ring packing, the VSP ring features a series of evenly folded inner arcs along the axial direction, alternately arranged. This geometric modification creates a saddle-like curved channel that disrupts straight-line fluid flow, breaking up laminar films and improving gas-liquid contact. The open arc structure maintains high voidage while the alternating arrangement prevents nesting.

The plastic VSP ring is molded from thermoplastic materials including PP, PE, PVC, CPVC, or PVDF — chosen based on service temperature and chemical environment. This makes it a direct alternative to the metal VSP ring (stainless steel 304/316) for corrosive applications where metal would suffer stress corrosion cracking.

Key geometric advantages:

  • • Alternating Inner Arcs: Disrupt directional fluid flow, preventing preferential paths and ensuring uniform distribution across the tower cross-section.
  • • Geometric Symmetry: Axial folding creates balanced mechanical stability, reducing nesting and bridging between adjacent rings.
  • • High Void Fraction: Open arc channels maintain low resistance to gas flow — typical pressure drop < 100 Pa/m at operating load.
  • • Corrosion Immunity: Plastic construction eliminates the risk of SCC that plagues metal packings in amine and acidic services.
Close-up of single plastic VSP ring showing alternating inner arc folds and hollow cross-section

Figure 2: Close-up of VSP ring inner arc structure — the alternating folds create tortuous flow paths for better liquid spreading.

2. Core Functions of the Plastic VSP Ring

The plastic VSP ring serves four critical functions in tower operations. Each is rooted in its unique alternating inner arc geometry:

01

Promote Uniform Gas-Liquid Distribution

How it works: The alternating inner arc structure disrupts the directional flow of fluids, preventing the formation of preferential paths. This ensures that both gas and liquid are evenly distributed across the tower cross-section, maximizing contact area.
Design Advantage: Compared to standard ring packings, the saddle-like curved channels guide fluid along arc paths rather than straight vertical lines, resulting in a more tortuous flow pattern that enhances distribution uniformity.
02

Reduce Channeling and Wall Flow

How it works: The saddle-like curved channels guide liquid downward along arc paths, directly reducing wall flow. The alternating arrangement also minimizes overlapping and bridging between adjacent rings, which are common causes of channeling in random packed beds.
Design Advantage: By changing the two ends into a rectangular-type contact surface (an improvement derived from the evolution of saddle ring design), bridging between packings is significantly reduced, maintaining high bed void fraction and uniform flow.
03

Enhance Mass Transfer Efficiency

How it works: By increasing the tortuosity of the gas path and prolonging liquid film residence time on the concave inner surfaces, the VSP ring provides a more effective mass transfer area than standard ring packings.
Design Advantage: The concave surfaces of the inner arcs "cradle" the liquid, increasing the effective interfacial area for gas-liquid contact. This leads to better absorption, desulfurization, and decarbonization performance at lower energy input.
04

Lower Pressure Drop

How it works: The open structure and streamlined inner arcs create a high void fraction, allowing gas to pass through with minimal resistance. This reduces the overall pressure drop of the tower system.
Design Advantage: Lower pressure drop translates directly into energy savings on fans, blowers, and reboilers. In vacuum towers where pressure drop is critical, plastic VSP rings can significantly improve operability and reduce operating costs.

3. Material Selection: PP, PE, PVC, CPVC, PVDF

FXSINO manufactures plastic VSP rings in five thermoplastic materials. Selection depends on operating temperature, chemical compatibility, and mechanical requirements:

Material Max Temp Chemical Resistance Best For
PP (Polypropylene) 100°C Excellent to acids, alkalis General absorption, FGD, hot water
PE (Polyethylene) 80°C Excellent; better UV resistance (black) Ambient cooling, outdoor scrubbers
PVC 60°C Excellent to acids, chlorine Chlor-alkali, acidic scrubbing
CPVC 90°C Superior to PVC at elevated temp Hot acidic service
PVDF 150°C Excellent to most chemicals incl. halogens High-temp amine, aggressive solvents
Plastic VSP ring samples in different materials: white PP, black PE, grey PVC, and natural PVDF

Figure 3: Material options — white PP, black PE, grey PVC, and natural PVDF VSP rings for different service conditions.

4. Performance Comparison with Other Plastic Packings

How does the plastic VSP ring compare against other common plastic random packings?

Packing Type (50mm) Voidage (%) ΔP @ F=1.5 (Pa/m) Surface Area (m2/m3) Relative Cost
Plastic VSP Ring 88–92 70–90 95–110 $$
Plastic Pall Ring 90–92 80–100 100–120 $$
Plastic Saddle (Intalox) 78–82 120–150 85–100 $
Multi-ball Hollow Ball ≥ 95 40–60 160–200 $

Verdict: Plastic VSP rings offer the best resistance to channeling and wall flow among plastic random packings, making them ideal for corrosive absorption and desulfurization. Choose Pall rings if you need maximum efficiency (lower HETP); choose VSP rings if you need superior distribution uniformity and corrosion resistance.

5. Typical Applications

  • • Absorption & Desorption Towers: For gas purification and recovery of SO2, HCl, NH3, and CO2. PP VSP rings handle hot, corrosive scrubbing liquids with excellent chemical resistance.
  • • Desulfurization & Decarbonization: Flue gas desulfurization (FGD) scrubbers and amine regenerator towers benefit from the VSP ring's anti-channeling design and uniform distribution.
  • • Chemical & Metallurgical Industries: Distillation, extraction, and stripping processes where temperatures stay within the plastic's service range (PP up to 100°C, PVDF up to 150°C).
  • • Environmental Protection: Wastewater stripping, VOC removal, and odor control — the corrosion-resistant plastic body ensures long service life without fouling.

6. Installation & Bed Depth

  • Dumping Method: Pour rings evenly across tower cross-section. Do NOT drop from excessive height (> 3m) — use a chute or sock to prevent breakage of thin-wall plastic rings.
  • Support Grid: Use a camel hump support grid with open area ≥ 80%. Bar spacing must be ≤ 0.6 × nominal ring size (e.g., ≤ 15mm for 25mm rings).
  • Bed Limiter: For vacuum or high-gas-velocity service, install a bed limiter / hold-down plate to prevent fluidization of light PP/PE rings.
  • Settling Allowance: Plastic rings can settle 2–5% after initial operation due to nesting and creep. Add 3% extra volume to initial charge.
  • Liquid Distribution: Critical for uniform wetting. Use a liquid distributor with ≥ 50 drip points per m2 for 25–38mm sizes; ≥ 25 points/m2 for 50mm+.
Plastic VSP ring packing being dumped into absorption tower showing even distribution

Figure 4: VSP ring packing being charged into an absorption tower — even distribution ensures uniform gas-liquid contact.

7. Quick FAQ

Q: VSP ring vs. Pall ring — which should I choose?

A: Pall rings have internal windows (fingers) that create more internal surface contact, giving slightly better mass transfer (lower HETP). VSP rings have no windows but feature alternating inner arcs that excel at preventing channeling and wall flow. Choose Pall rings for distillation/efficiency-critical service; choose VSP rings for corrosive absorption and services prone to maldistribution.

Q: Can I use plastic VSP rings in high-temperature amine service?

A: PP grade handles up to 100°C continuously; PVDF handles up to 150°C. For amine regenerator reboiler temperatures (120–150°C), PVDF is recommended. For higher temperatures, metal VSP rings (304/316 SS) are the correct choice.

Q: What is the bulk density of plastic VSP rings?

A: For 50mm PP VSP rings, expect ~60–70 kg/m3 (including ~5% void settling). PE is slightly heavier at ~75–85 kg/m3. This is light enough that most towers don't need structural reinforcement — unlike ceramic packings at 700+ kg/m3.

Get a Quote for Plastic VSP Ring Packing

FXSINO is a manufacturer of tower packing & internals — plastic VSP rings, Pall rings, support grids, and liquid distributors. Custom sizes, PP/PE/PVC/CPVC/PVDF materials, shipped worldwide.

Tell us your tower diameter, bed depth, service fluid, operating temperature, and preferred material. We'll recommend the right ring size, calculate total volume, and provide a same-day quote with lead time. FXSINO supplies complete packed tower solutions — from support grids and bed limiters to liquid distributors.

Contact FXSINO: jackieqiu9202@gmail.com | +86 18507999558

leave a message
leave a message
If you are interested in our products and want to know more details,please leave a message here,we will reply you as soon as we can.
submit

Home

Products

whatsApp

contact