Pall rings are one of the most basic, widely used types of tower packing. They are versatile, affordable options for distillation, absorption and stripping operations — including high-volume and high-temperature processes. Pall rings packing improved previous methods of packing so much so that it’s still valued today as one of the most efficient packing methods.
As a leading supplier of random tower packing, MACH Engineering manufactures plastic, ceramic and metal pall rings for industrial use. Our products combine excellent quality with an affordable price point — and we stand behind everything with some of the most knowledgeable customer service in the industry.
Pall Rings vs. Raschig Rings
Friedrich Raschig, a German chemist, first invented Raschig ring packing as a way to perform efficient distillation. Raschig rings are cylindrical tubes that have equal height and diameter. They’re typically made of metal or ceramic, though glass is also used in some applications. When used for distillation, vapor will condense on the ring’s surfaces. While the vapor and liquid pass each other in the small space, they try to achieve equilibrium. As a result, the material that is harder to evaporate goes downward in the tube, and the easily evaporable material goes upward.
The Raschig ring is considered the first generation of ring packing, and since its invention, the ring design has been altered to be more efficient and handle higher capacities. The pall ring was a significant advancement for random packing. Pall rings are similar to Raschig rings in that they have equal height and diameter. The significant difference between the two is that pall rings have windows and tabs punched in the walls. Most commonly pall rings are made of metal, ceramic or plastic, depending on the conditions of the application.
Adding the windows and tabs increased the capacity and efficiency of the ring significantly, as the gas and liquid distribution is improved. The tabs being folded into the center of the tube creates drop points, allowing more internal surface area to be used. This improved packing design is flexible, has low resistance and high separation capabilities.
Metal Pall Ring Packing Details and Specifications
Pall rings are conventional-shaped packing that offer a low price compared to other modern packing methods at a cost of performance. A pall ring’s geometry minimizes the number of contours and crevices that cause liquid to be held up, thus enabling high liquid and gas transfer rates. The interior and exterior surface of the pall ring provide effective distribution of liquids and gases.
MACH’s pall rings feature a design similar to a Raschig ring, but with the addition of a series of inward tabs that facilitate improved flow and greater efficiency. With a large surface area, but a minimal number of crevasses, they are effective at preventing entrainment. This type of design has been in use for more than 50 years and is trusted in many demanding applications.
Materials and Sizes of Metal Pall Rings
MACH Engineering manufactures metal pall ring packing from 304, 316, 304L and 316L stainless steel, as well as carbon steel and aluminum. Carbon steel is cost-effective and durable, but not suitable for use in corrosive environments. Stainless steel pall rings and aluminum pall rings offer better corrosion resistance — specifically the 316 and low-carbon 316L varieties — but are more expensive.
Available sizes include 1″, 1.5″, 2″ and 3″. For detailed specifications and more information about finding the right size and quantity for your application, get in touch with a MACH Engineering representative directly.
|Nominal Size (in)||1 (25 mm)||1 1/2 (38 mm)||2 (50 mm)||3 (76 mm)|
|Void Fraction (%)||96.1||96.4||97||97|
|Geometric Surface Area (ft2/ft3)||53.0||58.0||42.7||32.0|
|Weight – SS304 (lb/ft3)||31.8||30.2||33.6||36.2|
|Packing Factor (1/ft)||103.6||57.9||42.7||30|
Key Benefits of Metal Pall Rings
Metal pall rings packing is popular because the ring’s metal material and design offer benefits that can improve your operation in several ways. Metal pall rings improve on the Raschig ring design to deliver several benefits, including:
- Higher loading capacity and throughput with minimal pressure drop
- Easily wettable compared to its plastic counterpart
- Higher mass transfer efficiency and better liquid/gas distribution
- Excellent overall versatility, with good resistance to fouling
- Excellent mechanical strength, for longer life and improved reliability
- Suitable for high-temperature applications
- Mechanically robust
Use our stainless steel pall rings in high temperatures, as well as acidic, alkali, high salt and other harsh environments. Ceramic and plastic varieties are available, as well — explore our website for details.
Applications and Industries
Metal pall rings’ versatility means they are ideal for many industrial processes — especially those that need both a high capacity and a low-pressure drop under vacuum. Some processes they can help with include H2S, NH3 and SO2 absorption, direct contact cooling and steam stripping. They are not typically used for liquid redistribution. Other metal pall ring applications might include decarbonization, degassing and heat recovery.
You’ll find our metal pall rings in reaction towers, distillation columns and quench towers, as well as other vessels. Metal pall rings packing is used in various industries, and MACH Engineering can cater to industries like pharmaceuticals, chemical and food processing, water and wastewater, refineries and petrochemical.
Request a Quote for Metal Pall Ring Packing Today
MACH Engineering is unique among other metal pall ring manufacturers in that we specialize exclusively in tower packing and related products and services. As a result, we are better positioned to provide expert advice and dedicated customer support. When you’re unsure which type of tower packing is best for your application, we can run process simulations or provide other engineering consulting services.
If you know you need carbon steel, aluminum or stainless steel pall rings, we have a large selection in stock and ready to ship. Contact us by phone to request a quote and find out how MACH products and services can help your operation.