As the core equipment of the drilling fluid solid control system, the spring selection of the vibrating screen directly affects the screening efficiency, equipment service life and operational stability. This article, in light of the characteristics of drilling conditions, systematically expounds the selection principles, type comparisons and key precautions of vibrating screen springs.

I. Core Principles for Selection

1. Load matching

The spring load-bearing capacity needs to be calculated based on the total weight of the screen box (including cuttings and drilling fluid) and the excitation force of the vibrating motor. For large vibrating screens (with a processing capacity > 100t/h), composite springs with a stiffness of ≥200N/mm should be selected. For medium and small-sized equipment, rubber springs can be used.

2. Vibration characteristic adaptation

•  Stiffness selection: Spring stiffness directly affects amplitude and frequency. Excessively high stiffness (> 150N/mm) is prone to cause resonance of the screen body, while excessively low stiffness (< 80N/mm) cannot suppress the impact of large rock debris.

• Damping performance: The internal friction coefficient of rubber springs (μ=0.15-0.3) is superior to that of metal springs (μ=0.05-0.1), which can reduce amplitude fluctuations and is suitable for high-viscosity drilling fluid conditions.
  

  
  

3. Environmental adaptability

• Temperature: The applicable temperature range for rubber springs is -20 to 80℃, while the temperature resistance range for composite springs can reach -40 to 120℃. They are suitable for polar regions or high-temperature well sites.

• Corrosion protection: For sulfur-containing oil and gas fields, stainless steel metal springs or acid-resistant rubber (such as fluororubber) should be selected.

Comparison of Mainstream Spring Types

Rubber spring

Composite spring

Metal spring

 Key Parameters for Selection

1. Preload calculation

According to the weight of the screen box (W) and the number of springs (n) :

F=nW×g×K

(K is the safety factor, taken as 1.2-1.5)

2. Fatigue life verification

The Miner criterion is adopted to evaluate the life under cyclic loading:

N=(Ka σa σ−1)m ⁻ ¹

(σ youdaoplaceholder0 ₁ represents the fatigue limit, σ youdaoplaceholder4 represents the stress amplitude, and m represents the material index)

Application Cases

• Solid control of shale gas Wells: Composite springs (steel core + fluororubber) are adopted,
  which can operate continuously for 1800 hours at 90℃ without deformation.

• The offshore drilling platform adopts stainless steel metal spring groups, which increase the salt spray corrosion resistance by
   five times and extend the maintenance cycle to six months.

Maintenance Points

1.Regular inspection: Check the spring deformation every 500 hours (allowable value < 2mm).

2. Lubrication Management: Metal springs should be lubricated with lithium-based grease (NLGI Grade 2) every quarter.

3. Replacement standard: Rubber springs must be replaced when the crack depth exceeds 1mm or the elastic modulus decreases by more than 15%.

The selection of springs for vibrating screens should take into account mechanical properties, environmental factors and economy. Through precise calculation and matching with working conditions, the solid control efficiency can be significantly improved (rock cuttings removal rate > 95%), and the equipment failure rate can be reduced (annual downtime < 8 hours). It is recommended to give priority to using composite springs to achieve the best balance between cost and performance.