The Architecture of the V-Wire: Engineering the “Non-Clogging” Miracle
The fundamental brilliance of the Johnson type screen—also known as the wedge wire screen—lies in its geometry. Traditional perforated pipes or slotted liners suffer from a fatal flaw: particles that are slightly smaller than the opening can become wedged halfway through, leading to a permanent reduction in flow and eventual well failure.
Our engineering team utilizes a continuous V-shaped profile wire, cold-rolled from high-grade stainless steel. By welding this wire onto a circular array of longitudinal support rods, we create an aperture that widens inwardly. This means any particle that passes through the outer “slot” will naturally fall through into the screen interior without getting stuck.
This self-cleaning characteristic is what separates our professional-grade screens from generic alternatives. In a deep-well environment, where chemical encrustation and sand infiltration are constant threats, the “open-area” ratio of our screens remains remarkably consistent over decades.
Material Science: The Stainless Steel Advantage
Choosing the right alloy is not merely a matter of cost; it is a calculation of the corrosive potential of the aquifer. Groundwater is rarely “just water”—it is a complex soup of dissolved CO2, H2S, chlorides, and varying pH levels.
Table 1: Chemical Composition of Stainless Steel Screen Grades
| Grade | Cr (%) | Ni (%) | Mo (%) | C (max %) | N (max %) | P (max %) | S (max %) |
| SS 304 | 18.0–20.0 | 8.0–10.5 | — | 0.08 | — | 0.045 | 0.03 |
| SS 304L | 18.0–20.0 | 8.0–12.0 | — | 0.03 | — | 0.045 | 0.03 |
| SS 316 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | 0.08 | — | 0.045 | 0.03 |
| SS 316L | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | 0.03 | 0.10 | 0.045 | 0.03 |
| SS 904L | 19.0–23.0 | 23.0–28.0 | 4.0–5.0 | 0.02 | — | 0.045 | 0.03 |
For standard irrigation wells, our SS 304 screens provide an excellent balance of cost and longevity. However, for industrial desalination or deep oilfield brine extraction, we recommend SS 316L or even SS 904L. The presence of Molybdenum (Mo) in 316L provides critical resistance to pitting corrosion in high-chloride environments. Furthermore, our “L” (Low Carbon) variants are essential for preventing intergranular corrosion in the heat-affected zones (HAZ) of the resistance welds, ensuring the structural integrity of the screen is not compromised by the manufacturing process itself.
Structural Integrity: Collapse Resistance and Tension
A well screen is subjected to immense hydrostatic pressure and the weight of the casing string above it. The design of the support rods—those vertical pillars inside the screen—is where our technical superiority is most evident. We don’t just use standard rods; we calculate the required moment of inertia for each project based on the planned depth and the expected differential pressure.
Table 2: Technical Specifications & Performance Parameters
| Parameter | Range / Standard | Impact on Well Performance |
| Slot Size (mm) | 0.05 mm – 20.0 mm | Controls sand filtration efficiency |
| Open Area (%) | 15% – 60% | Affects flow velocity and drawdown |
| Support Rod Type | Round, Triangle, Flat | Determines collapse resistance |
| Max Pressure | Up to 10 MPa (Project specific) | Ensures safety at great depths |
| End Connections | Threaded (NPT/BTC), Flanged, Welded | Affects installation speed and seal |
By optimizing the Open Area, we reduce the “Entrance Velocity” of the water. High-velocity water causes turbulence, which in turn accelerates corrosion and encourages mineral scale buildup. Our screens are designed to keep entrance velocities below 0.03 m/s, which is the industry gold standard for minimizing well maintenance costs.
Precision Manufacturing: The Fusion Point
Every intersection of the V-wire and the support rod in our screens is joined by Resistance Welding. Unlike traditional arc welding, which introduces filler material and excess heat, resistance welding uses electrical current and pressure to fuse the materials at the molecular level. This creates a bond that is actually stronger than the wire itself.
Our CNC-controlled winding machines ensure that the slot width is consistent within a tolerance of ±0.01mm. In an aquifer where the sand grain distribution is finely graded, a “loose” tolerance in the slot size can lead to catastrophic sand pumping, which destroys pump impellers and eventually causes the well to collapse.
Why Our Johnson Type Screens are the Industry Benchmark
Our commitment goes beyond simply selling a product; we provide a geological partnership. When you order from us, our engineers analyze your “Sieve Analysis” data of the formation sand. We don’t just sell you a 0.5mm slot; we calculate the exact slot size required to retain 90% of the formation while allowing the finest 10% to be “developed” out, creating a natural gravel pack around the screen.
Our stainless steel Johnson type wire well screens offer:
-
Superior Longevity: A lifespan of 30+ years in aggressive environments.
-
Reduced Pumping Costs: Lower drawdown due to high open areas.
-
High Strength-to-Weight Ratio: Easier handling during installation without risking collapse.
-
Traceability: Every screen is shipped with a full material certificate (MTC) and quality inspection report.
Whether you are rehabilitating an old well or embarking on a massive municipal water project, the filtration interface is the one place where quality cannot be compromised. Our screens represent the pinnacle of wire-wrap technology, ensuring that what comes out of your well is pure, consistent, and sand-free.
To provide a rigorous technical calculation for your well design, we must move beyond generalities and into the mathematics of hydraulic efficiency and soil mechanics. The performance of a Stainless Steel Johnson Type Wire Well Screen is governed by the relationship between the formation’s particle size distribution and the screen’s hydraulic capacity.
Part 1: Determination of Slot Size (Sieve Analysis)
The most critical decision in well design is the slot width. Selecting a slot that is too large leads to “sand pumping,” which destroys pumps; selecting one too small leads to excessive “drawdown” and energy waste.
In a naturally developed well (without an artificial gravel pack), we typically apply the D-percentile rule. We analyze the formation samples and plot a grain size distribution curve.
-
Reliable Filtration Rule: For most stable aquifers, the slot size is selected to retain 60% to 70% of the formation ($D_{60}$ or $D_{70}$). The finer 30% to 40% of the material is intended to be drawn through the screen during the “well development” phase, creating a highly permeable natural envelope of coarser pebbles around the screen.
-
Formula for Slot Selection:
$$Slot\ Width \approx D_{60} \text{ (of the formation sample)}$$
Part 2: Open Area and Entrance Velocity
The “Open Area” is the percentage of the screen surface that allows water to pass. Unlike perforated pipes, our Johnson type screens can achieve up to 60% open area, which is vital for reducing Entrance Velocity ($V_e$).
The industry standard (to prevent encrustation and corrosion acceleration) is to keep $V_e$ below 0.03 m/s (roughly 0.1 ft/sec).
To calculate the required screen length ($L$) or diameter ($D$) for a target flow rate ($Q$), we use:
Where $A_o$ is the total open area of the screen surface.
If your aquifer has a high concentration of iron or manganese, we recommend an even lower entrance velocity to prevent the pressure drop that triggers mineral precipitation (clogging).
Table 3: Hydraulic Capacity for Standard 6-inch (168mm) Johnson Screen
| Slot Size (mm) | Open Area (%) | Intake Capacity (m3/h/m) at 0.03 m/s | Structural Grade |
| 0.25 | 12.5% | 18.2 | Heavy Duty |
| 0.50 | 22.8% | 33.1 | Standard |
| 0.75 | 31.4% | 45.6 | Standard |
| 1.00 | 38.2% | 55.5 | Standard |
| 2.00 | 55.1% | 80.1 | Light/Medium |
Part 3: Deep Well Collapse Resistance (The Support Rod Factor)
As we go deeper, the hydrostatic pressure and the weight of the “filter pack” (if used) exert massive radial pressure on the screen. While the V-wire provides the filtration, the internal support rods provide the structural skeleton.
Our technical department uses the Lundquist Equation to calculate the critical collapse pressure ($P_c$). By adjusting the shape and frequency of the support rods (e.g., using 3.0 x 5.0 mm “teardrop” rods instead of 2.0 mm round rods), we can increase the collapse strength by up to 400% without significantly reducing the internal diameter.
Why Our Technical Consultation Matters
When you partner with us, you aren’t just buying a commodity. We provide a Project Design Verification report that includes:
-
Velocity Profiling: Ensuring the flow is laminar (smooth) rather than turbulent.
-
Material Compatibility: Analyzing your water chemistry (pH, TDS, $Cl^-$) to confirm if SS 304L is sufficient or if the project requires the molybdenum-enhanced SS 316L.
-
Tension Load Analysis: Calculating the maximum “hang weight” the screen can support during installation in deep bores.
Our screens are manufactured with a continuous-slot design, meaning there are no “dead zones” or interruptions in the flow. This ensures that the entire circumference of the aquifer is being utilized, which maximizes the specific capacity of your well.
The water well screen is an important component of a well that allows water to flow into the well while preventing sediment and other debris from entering. The screen is typically located at the bottom of the well, near the aquifer. This is done to ensure that only clean water is collected and that any sediment or dirt is filtered out. The screen is typically made from a perforated pipe or other type of material that has small openings to allow water to pass through while blocking sediments from entering. Abter well screen is manufactured with a continuous v-shaped slot to reduce the entrance velocity of water and encrustation rates. Besides, Filson well screen has a large surface area without clogging, thus provide superior filtration performance. Well screen slot size selection is a critical step, typically based on the particle size analysis of the formation sample. With the standard slot size range from 0.005” to 0.5”, Filson well screen can control sand particles and silt from the well perfectly. Advantages of Water Well Screens 1. The V-shape section plane of water well screens creates the continuous slot, which can avoid blockage and make sure of the unimpeded water. Read more
PARAMETER Geothermal Pipe based well screen specification: Nominal Diameter Pipe OD(mm) Weight lb/ftW.T[mm] Hole size In Holes per foot Total Areaofholes in2/ft Screen OD (in) 2-3/8 60 4.6[4.83] 3/8 96 10.60 2.86 2-7/8 73 6.4[5.51] 3/8 108 11.93 3.38 3-1/2 88.9 9.2[6.45] 1/2 108 21.21 4.06 4 101.6 9.5[5.74] 1/2 120 23.56 4.55 4-1/2 114.3 11.6[6.35] 1/2 144 28.27 5.08 5 127 13[6.43] 1/2 156 30.63 5.62 5-1/2 139.7 15.5[6.99] 1/2 168 32.99 6.08 6-5/8 168.3 24[8.94] 1/2 180 35.34 7.12 7 177.8 23[8.05] 5/8 136 42.16 7.58 7-5/8 194 26.4[8.33] 5/8 148 45.88 8.20 8-5/8 219 32[8.94] 5/8 168 51.08 9.24 9-5/8 244.5 36[8.94] 5/8 188 58.28 10.18 10-3/4 273 45.5[10.16] 5/8 209 64.79 11.36 13-3/8 339.7 54.5[9.65] 5/8 260 80.60 14.04 What is Geothermal Well Screen？ Geothermal well screens are an essential component of a geothermal well system. They are used to filter and protect the geothermal well from debris and other contaminants that can be harmful to the system. Sand Control Screens are designed to be durable and reliable, providing long-term protection for the well. The geothermal well screen is a cylindrical tube made of a perforated metal or plastic material. The perforations are designed to allow Read more
Pre Packed Sand Screen contains perforated base pipe, inner and outer screen jackets and graded sand between the jackets. It is a modification of wire wrapped screen which is used in well sorted sand or stand-alone completion. Graded sand, with or without resin coating, is considered as a filter for reservoir particles. Wire wrapped pre Pre Packed Sand Screen is used in wells where conventional gravel packing is not feasible or economical. The thickness of gravel layer can be varied to meet special requirement. What Is the Function of Gravel Pack? Gravel packing is one of popular sand-control technique used in oil, water and gas wells. It stabilizes the borehole and filters the sand from the flow, only allowing very fine particles in. Pre Packed Sand Screen wire wrapped sand screen brings it into full play in maximizing production as well as controlling the sand. Diameter: 168mm Material: stainless steel,carbon steel,etc Slot: 0.2mm End Connection: thread,coupling,etc thickness: 10mm Pre Packed Sand Screen PRODUCT SPECIFICATIONS Base Pipe Gravel Pack Perforations Screen OD (in.) ID (in.) Weight (lbs.) Coupling OD (in.) Thickness (in.) Size (in.) Holes/ft. OD (in.) Cylinder Area (sq. in./ft) 006 GA Inlet Area (sq. in./ft) 1.9 1.61 2.75 Read more
1. Grade: SUS 304 SUS304L, SUS316, SUS316L, or carbon steel 2. Slot Size: 0.02mm~15mm 3. Standard: DIN AISI ASTM 4. Certification: ISO9001, API 5CT 5.Pipe based well screens consist of base pipe,all-welded wedge wire screen and supporting rod.The base pipe is perforated or slotted API casing pipe,the base pipe can be stainless steel or carbon steel API 5CT casing.The all-welded wedge wire screens are welded together with base pipe by supporting rod. 6.Features of Pipe Based Well Screens: 1)Higher filtering accuracy: all-welded wedge wire screens as screen jacket with vee opening design makes the filtering accuracy higher,which can control sand better. 2)Excellent strength and resistance to deformation: The base pipe inside,the outside can be protected with the protection jacket added according to requirements,the integrated strength of the perforated base pipe only decreases 2~3% compared with the standard casing/oil tubing,so the pipe based well screens have enough integrated strength to resist to the pressure caused by strata.Even if some part of the well screens deformed,the slot of this part will not be widened,which makes higher sand controlreliability 3)More choices: the material of screen jacket can be stainless steel or carbon steel,the material can be chosen as per customers'requirement. 4)The smaller slot Read more
1. Introduction of Slotted Casing Pipe Casing pipe is a large-diameter pipe that serves as the structural retainer for the walls of oil and gas wells, or well bore. It is inserted into a well bore and cemented in place to protect both subsurface formations and the wellbore from collapsing and to allow drilling fluid to circulate and extraction to take place. Slotted casing pipe is a type of casing pipe that has slots machined into its surface. These slots are used to help control the flow of water, oil, and gas in a well bore. The slotted casing pipe is designed to allow water, oil, and gas to flow through the slots while preventing sand and other debris from entering the well bore. Slotted casing pipe is commonly used in oil and gas wells, water wells, and geothermal wells. 2. Types of Slotted Casing Pipe There are two main types of slotted casing pipe: open slot and perforated slot. Open slot casing pipe has slots that are cut into the surface of the pipe in a straight line. These slots are usually spaced evenly apart and are typically about 1/4 inch wide and 1/4 inch deep. Perforated slot Read more
Applications of Perforated Pipe: Perforated well screen is a type of filter used in oil and gas wells. It is designed to control the flow of oil and gas from the well, while preventing sand and other debris from entering the well. perforation in the context of oil wells refers to a hole punched in the casing or liner of an oil well to connect it to the reservoir. Creating a channel between the pay zone and the wellbore to cause oil and gas to flow to the wellbore easily. In cased hole completions, the well will be drilled down past the section of the formation desired for production and will have casing or a liner run in separating the formation from the well bore. The final stage of the completion will involve running in perforating guns, a string of shaped charges, down to the desired depth and firing them to perforate the casing or liner. A typical perforating gun can carry many dozens of explosive charges. Commonly, perforation guns are run on E-line as it is traditional to use electrical signals from the surface to fire the guns. In more highly deviated wells, coiled tubingmay be used. Newer technologies Read more
