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Wire Mesh Lehr Belts

Lehr Belts feature a balanced weave wire construction, composed of alternating right- and left-hand flattened spirals securely seated in crimped connector rods. The belt edges are welded to enhance durability and stability.

Balanced Spiral Woven Conveyor Belts

Standard Balanced Spiral Woven Belt Enquiry Form

Compound Weave Conveyor Belts

Compound Weave Conveyor Belt Enquiry Form

Beijing PFM SCREEN Mesh Conveyor Belt Product Catalog 2024

Overview
Specification
Applications
Downloads
FAQ

Overview

Wire Mesh Lehr Belts are metal conveyor belts purpose-built for the glass industry's annealing and decorating lehrs. They carry glass containers — bottles, jars, tumblers, and lighting glass — through a precisely controlled temperature tunnel where gradual cooling from the annealing point (typically 500–650°C for soda-lime glass) eliminates internal stresses formed during shaping. The result is glass that is stronger, more consistent, and less prone to spontaneous fracture in service.

PFM SCREEN has designed and manufactured wire mesh lehr belts since 1987, supplying glass container manufacturers, decorating lehr operators, and industrial furnace builders across 60+ countries. Our lehr belts are built to run continuously at temperatures up to 1200°C, maintain straight tracking without lateral drift, and deliver multi-year service life under the demanding thermal cycling of production lehrs. Every belt is manufactured to your furnace's exact specifications — width, wire gauge, pitch, and material grade — with welded edges as standard.

Wire Mesh Lehr Belts — glass annealing application Wire Mesh Lehr Belts — balanced weave detail

Key Features

• Smooth Conveying Surface: The flattened spiral wire profile creates a flat, even contact surface that keeps glass containers upright and prevents tip-over at lehr conveying speeds — critical for lightweight glassware such as wine bottles and small jars.

• Minimal Belt Stretch: Crimped cross rods lock each spiral coil in position, restraining belt elongation under load and thermal expansion. This reduces the frequency of belt take-up adjustments and extends operating life.

• Accurate Straight Tracking: The balanced weave construction — equal numbers of left-hand and right-hand spirals — cancels lateral drift forces, keeping the belt centered in the lehr frame without constant manual realignment.

• Customizable Widths: Available from 35 mm to 5000 mm to fit any lehr furnace configuration, with wire gauge, pitch, and material grade specified to your operating temperature and load requirements.

Construction and Materials

Construction

• Balanced weave structure, comprising alternating right and left-hand flattened spirals connected by crimped rods. This design ensures locked-in spirals for straight tracking and product stability. Edges are welded for added durability.

• Compound weave structure, balanced spiral belt with multiple spirals and cross rods per pitch, resulting in minimal apertures and a flat surface. This structure ensures a close and flat mesh, ideal for conveying very small items.

Wire Mesh Lehr Belt — Balanced weave structure Wire Mesh Lehr Belt — Compound weave structure

Materials

• Carbon / Chrome Molybdenum Steel: Max continuous operating temperature 538°C. Cost-effective choice for lower-temperature annealing zones or pre-annealing applications.

• 430 Stainless Steel: Max operating temperature 650°C. High chromium content provides good oxidation and corrosion resistance. The most widely used material for standard glass annealing lehrs, and an established replacement for chrome molybdenum steel in conventional annealing operations.

• 304 Stainless Steel: Max operating temperature approximately 900°C. Superior corrosion and oxidation resistance compared to 430 SS. Recommended for higher-temperature decorating lehrs and demanding industrial furnace applications.

• 314 Stainless Steel / Nickel Chrome Alloy: Max operating temperature up to 1200°C. Specified for the most extreme high-temperature environments, including sintering and brazing furnaces.

Belt Types

Round Wire Spirals Lehr Belts

Round Wire Spirals Lehr Belts

Spiral coils made from round (circular cross-section) wire. Offers greater air permeability and a more open belt surface at lower cost. Suitable for glass containers with a stable base that do not require an especially flat support surface.

Flattened Wire Spirals Lehr Belts

Spiral coils made from flat (rectangular cross-section) wire, typically 1.2×0.8 mm to 4×2 mm. The wider coil profile creates a smoother, more uniform belt surface with a larger contact footprint on the cross rods. Preferred for small-base containers, lightweight glassware, and decorating lehr applications where surface flatness and product stability are critical.

Compound Weave Lehr Belts ( Round or Flattened Wire )

Multiple cross rods inserted per coil pitch, producing a tight, near-closed mesh with minimal aperture size. Maximum surface flatness and product support. Ideal for very lightweight glassware or applications where the smallest possible belt opening is required.

Edge Availability

Lehr Belts with Welded Edge

Lehr Belts with Welded Edge

The standard edge finish for glass annealing lehr belts. Both the spiral coil ends and cross rod ends at each belt edge are welded together, eliminating protruding cut wire ends. This prevents edge unraveling under the repeated thermal cycling of lehr operation, reduces installation injury risk, and extends belt service life by removing the stress concentration point at unsupported wire ends.

Specifications

Balanced weave structure

A: Spiral Wire Pitch (mm) B: Spiral Wire Diameter (mm)

C: Cross Rod Pitch (mm) D: Cross Rod Diameter (mm)

Compound weave structure

A: Spiral Wire Pitch (mm) B: Spiral Wire Diameter (mm)

C: Cross Rod Pitch (mm) D: Cross Rod Diameter (mm)

E: Number of Cross Rod per Spiral Coil

Material	Carbon Steel, 430 Stainless Steel, 304 Stainless Steel, 314 Stainless Steel, etc.
Spiral Wire Diameter	Round wire: 1 to 4 mm Flat wire: 1.2 x 0.8 mm to 4 x 2 mm
Spiral Wire Pitch	3 to 33 mm
Cross Wire Diameter	1.5 to 5 mm
Cross Wire Pitch	6.5 to 40 mm
Belt Width	35 mm to 5000 mm
Operating temperature	Operating temperature: Carbon steel: up to 538°C 430 Stainless Steel: up to 650°C 304 Stainless Steel: up to 900°C 314 SS / Nickel Chrome: up to 1200°C

Applications

Wire Mesh Lehr Belts are used across a range of high-temperature industrial processes:

• Glass Annealing Lehrs: Transporting glass containers — bottles, jars, tumblers, and lighting glass — through a controlled cooling zone (typically 500–650°C for soda-lime glass) to eliminate internal stresses and improve mechanical strength. The primary application for lehr belts.

• Glass Decorating Lehrs: Conveying decorated glassware through firing ovens where ceramic or organic inks are cured and fused onto the glass surface at temperatures up to 650°C.

• Sintering Furnaces: Continuous conveyance of powder-metallurgy or ceramic components through sintering ovens at temperatures up to 1200°C, using 314 SS or Nickel Chrome alloy belt grades.

• Brazing Furnaces: Transport of metal assemblies through controlled-atmosphere brazing ovens for flux or furnace brazing operations.

• Baking Ovens: High-temperature baking conveyor applications where a flat, heat-resistant open-mesh belt surface is required.

Wire Mesh Lehr Belts for Sintering Wire Mesh Lehr Belts for Glass Annealing Lehr

Wire Mesh Lehr Belts for Brazing Wire Mesh Lehr Belts for Baking Ovens

Balanced Spiral Woven Conveyor Belts

Standard Balanced Spiral Woven Belt Enquiry Form

Compound Weave Conveyor Belts

Compound Weave Conveyor Belt Enquiry Form

Beijing PFM SCREEN Mesh Conveyor Belt Product Catalog 2024

Frequently Asked Questions

Common questions about wire mesh lehr belts, glass annealing belts, and high-temperature conveyor belts

Q1. What is a wire mesh lehr belt and how does it function in glass annealing?

A wire mesh lehr belt is a continuous metal conveyor belt engineered specifically for glass annealing furnaces (lehrs). It transports glass containers — bottles, jars, tumblers, and lighting glass — through a carefully controlled temperature tunnel where the glass is first heated to its annealing point (typically 500–650°C for soda-lime glass) and then cooled gradually to ambient temperature. This controlled thermal cycle eliminates internal stresses formed during the shaping process, preventing spontaneous cracking and improving mechanical strength.

PFM SCREEN lehr belts use a balanced weave construction — alternating right-hand and left-hand flattened spirals interlocked by crimped cross rods — which provides a smooth, flat conveying surface with minimal apertures. The balanced weave ensures the belt runs straight without lateral drift, critical in lehrs where belt misalignment can cause product spillage or belt-to-frame contact damage.

Q2. What materials are available for lehr belts, and what temperatures can they withstand?

PFM SCREEN lehr belts are available in the following materials, each suited to different operating temperature ranges:

Material	Max Operating Temp.	Typical Use Case
Carbon / Chrome Molybdenum Steel	Up to 538°C	Low-temperature or pre-annealing lehrs
430 Stainless Steel	Up to 650°C	Standard glass annealing lehrs; replacement for 3% CrMo
304 Stainless Steel	Up to 900°C	Higher-temperature decorating or industrial lehrs
314 / Nickel Chrome Alloy	Up to 1200°C	Sintering, brazing, high-temperature industrial ovens

430 Stainless Steel is the most common choice for conventional glass annealing lehrs operating below 650°C. For higher-temperature processes such as sintering or brazing, 304 SS or NiCr alloys are recommended.

Q3. What is the difference between balanced weave and compound weave lehr belts?

Balanced Weave Lehr Belts consist of a single layer of interlocking spiral coils connected by crimped cross rods. Each spiral alternates direction (left-hand / right-hand) to create a self-balancing structure that tracks straight and resists lateral drift. The aperture size and surface openness are determined by the coil pitch and cross rod pitch. This is the most common lehr belt type for glass containers and is available in round or flat wire spirals.

Compound Weave Lehr Belts use multiple cross rods per coil pitch, resulting in a much tighter, flatter mesh surface. This near-closed surface is better suited for conveying very small items or fragile lightweight products that could tip or drop through wider apertures. Compound weave belts have a higher material density and greater weight per unit area, which also increases thermal mass — a consideration for energy efficiency in short lehr lines.

For most standard glass annealing operations (bottles, jars, tumblers), balanced weave belts are the preferred choice. Compound weave belts are used where a particularly close or flat mesh is required.

Q4. What is the difference between round wire and flat wire spirals in lehr belts?

Round Wire Spiral Lehr Belts use spiral coils made from wire with a circular cross-section. Round wire belts offer a slightly more open conveying surface, greater air permeability, and are generally lower in cost. They are well suited for glass products with a stable base that do not require an especially flat support surface.

Flat Wire Spiral Lehr Belts (also called flattened wire spirals) use coils made from wire that has been rolled to a rectangular cross-section, typically in ratios such as 1.2×0.8mm up to 4×2mm. The flattened profile results in a wider contact footprint with the cross rods, creating a smoother, more uniform belt surface. Flat wire lehr belts are preferred for containers with smaller bases, lightweight glassware, or decorating lehr applications where surface flatness and product stability are critical.

Q5. What belt widths and wire dimensions are available?

PFM SCREEN manufactures wire mesh lehr belts across a wide range of dimensions to match lehr furnace configurations worldwide. Our standard specification range is as follows:

Parameter	Range
Belt width	35mm to 5000mm (custom widths available beyond 5m)
Coil wire diameter (round)	1.0mm to 4.0mm
Coil wire size (flat)	1.2×0.8mm to 4×2mm (W×H)
Cross rod diameter	1.5mm to 5.0mm
Cross rod pitch	6.5mm to 40mm
Coil wire pitch	3mm to 33mm

All dimensions can be customized to match your existing lehr furnace or OEM equipment specifications. Contact us with your lehr model or dimensional drawing for a fast quotation.

Q6. What edge finishes are available for lehr belts?

The standard and most widely used edge finish for lehr belts is the welded edge. In a welded-edge belt, both the coil wire ends and the cross rod ends at each belt edge are welded together, eliminating sharp, protruding wire ends. This prevents edge unraveling, reduces the risk of injury during installation, and extends belt life by minimizing the stress concentration that can occur at free-wire edges in high-temperature cycling environments.

Welded edges are the recommended choice for all glass annealing and decorating lehr applications. For specialist requirements such as very wide belts, chain-driven configurations, or specific OEM frame designs, alternative edge treatments including knuckled or looped edges can be discussed with our engineering team.

Q7. Besides glass annealing, what other industrial applications are lehr belts used in?

While glass annealing is the primary and most common application, PFM SCREEN wire mesh lehr belts are also used across a range of high-temperature industrial processes:

• Glass decorating lehrs — transport of decorated glassware through firing ovens where ceramic or organic inks are cured and fused onto the glass surface.
• Sintering furnaces — conveyance of powder-metallurgy or ceramic components through continuous sintering ovens at temperatures up to 1200°C.
• Brazing furnaces — movement of metal assemblies through controlled-atmosphere brazing ovens where flux or furnace brazing joins components.
• Baking ovens — high-temperature baking applications where a flat, heat-resistant mesh surface is required.
• Tunnel kilns — conveyance of ceramic or glass objects through firing zones in continuous tunnel kilns.

If your application involves temperatures above 538°C and requires a stable, flat mesh conveying surface, a lehr-type belt is likely the correct solution. Contact us to discuss material selection and dimensional requirements.

Q8. How do I specify and order a replacement lehr belt?

To generate an accurate quotation for a replacement lehr belt, please provide the following information:

• Belt width (mm) — measured across the full width of the belt, inside the lehr frame
• Belt length (mm or m) — total loop length of the belt; the lehr model number is also helpful
• Weave type — balanced weave or compound weave
• Wire profile — round wire or flat wire spirals
• Wire dimensions — coil wire diameter and cross rod diameter if known
• Pitch — coil pitch and cross rod pitch if known, or a sample photo of the existing belt
• Material grade — existing belt material or the operating temperature range of your lehr
• Edge type — welded edge (standard) or other

If you have an existing belt, a physical sample or a photograph with a ruler for scale is the fastest way to confirm specification. Send your requirements to [email protected] or use the WhatsApp button below for a rapid response.