I. Core Functions

1. Spindle Sealing: Leakage and Air Ingress Prevention

The packing material tightly wraps around the shaft sleeve's outer surface; compression via the gland creates a radial seal, effectively preventing slurry (containing sand/grit), sewage, or process fluids from leaking at the shaft extension. It also prevents air suction caused by negative pressure—which could lead to pump cavitation, loss of prime, or vibration—thereby ensuring stable hydraulic performance.

2. Shaft Sleeve Protection and Wear Reduction

The soft packing material does not damage the metal shaft sleeve directly. Through lubrication, cooling, and cushioning effects, it minimizes dry friction and heat damage caused by high-speed rotation, extending the sleeve's service life and reducing the frequency of replacing wear parts.

3. Vibration Damping, Noise Reduction, and Operational Buffering

The packing possesses inherent toughness and plasticity, allowing it to absorb minor operational vibrations and cushion against pressure pulsations in the medium. This results in smoother shaft rotation and reduced abnormal noise or oscillation.

4. Simple Structure and Low Maintenance Costs

Compared to mechanical seals, packing seals are resistant to particles and impurities, tolerant of brief dry running, quick to maintain, and low in cost. They are ideally suited for the harsh operating conditions of slurry pumps and serve as the preferred sealing method for industrial transfer pumps.

II. Product Structure and Working Principle

1. Structural Composition

The slurry pump packing consists of square-braided, flexible packing material featuring a precise square cross-section, uniform density, and a tight fiber structure. It is supplied in rolls or rings to fit various stuffing box dimensions.

The complete packing seal assembly comprises the following layers:

- Innermost: Water seal ring (lantern ring)

- Middle section: Multiple layers of sealing packing (primary sealing zone)

- Outermost: Packing gland (for compression and securing)

2. Working Principle

Uniform compression via gland bolts causes the packing to contract radially and grip the shaft sleeve surface tightly. External clean flush water enters the packing assembly through the water seal ring, providing lubrication, cooling, and flushing of grit/sediment while preventing dry friction. This creates a dynamic seal with controlled, minimal leakage (slight dripping is a normal operating condition). Slurry pump gland seals do not require a completely leak-free state; slight dripping carries away heat and fine sand, preventing shaft burnout, sleeve wear, and seizure.

Classification of Common Materials and Operating Conditions (General + Warman-Compatible Materials)

Based on standard practices for the full range of Warman slurry pumps, the mainstream packing materials available on the market fall into the following categories, suited to various conditions involving corrosion, temperature, and particulate matter:

1. Tallow-Impregnated Graphite Packing (Standard for General Applications)

- Material: Cotton yarn + tallow impregnation + graphite lubrication

- Characteristics: Soft, good self-lubrication, low cost, easy to install, non-abrasive to shaft sleeves

- Applications: Clean water, general sewage, low-concentration silt/sand, ambient temperature/standard conditions

- Compatibility: Standard coal washing pumps, sewage pumps, low-wear slurry pumps

2. High-Water-Based Graphite Packing (Most Common in Industrial Applications)

- Material: High-strength synthetic fiber + graphite impregnation

- Characteristics: High-temperature resistant, wear-resistant, good resilience, resistant to hardening or failure

- Applications: Moderate sand content, ambient temperature slurry, power plant auxiliary water pumps

- Advantages: Longer service life than tallow packing; resistant to drying, cracking, or slurry leakage

3. Aramid Fiber Packing (Specialized for High-Wear Applications)

- Material: Aramid (Kevlar) high-strength, wear-resistant fiber

- Characteristics: Extremely wear-resistant, erosion-resistant, high-pressure resistant, high tensile strength (resistant to breakage)

- Applications: High-concentration tailings, coarse-particle slurry, coal washing heavy media, high-pressure transfer pumps

- Compatibility: Primary material for Warman AH/HH heavy-duty, high-wear slurry pumps

4. PTFE (Teflon) Packing (Corrosion-Resistant Applications)

- Material: Pure PTFE fiber; acid/alkali-resistant anti-corrosion formula

- Characteristics: Resistant to weak acids and alkalis, corrosion-resistant, rust-proof, scale-resistant

- Applications: Desulfurization slurry, chemical wastewater, corrosive media

- Compatibility: Desulfurization pumps, chemical slurry pumps; used with C22/C23 material shaft sleeves

5. Carbon Fiber Gland Packing (High-Temperature, High-Pressure, Highly Corrosive)

- Material: Carbon fiber with graphite impregnation

- Features: High-temperature resistance, good thermal conductivity, excellent self-lubrication, and aging resistance

- Applications: High-temperature slurries, highly corrosive media, and continuous 24-hour operation

Standard Specifications (Compatible with Warman Pumps)

Packing for the entire Warman slurry pump series features a universal square cross-section design; industry-standard sizes include:

6×6mm, 8×8mm, 10×10mm, 12×12mm, 14×14mm, 16×16mm