Soloflo - Product Overview - Wedge opening screens for ground water abstraction pressure relief dewatering boreholes construction engineering drillers

By: Soloflo  11-11-2011
Keywords: Screens, Pressure Relief, Wedge Opening

Product Overview

Engineers worldwide accept the wedge design to be resistant to clogging. This patented design is made by injection moulding using virgin non corrosive engineering grade polymers for specific ground conditions which saves on initial cost, maintenance and replacement.

The design also incorporates parallel outer fins which enhance compressive strength underground and radial water flow to reduce energy loss. These outer fins also protect the wedge shaped openings from damage during transport, handling and installation.

The first applications were in the mid 1980’s for agricultural subsoil drains at Meerlust Estates and De Hoop Estates in South Africa and continue to work as designed after more than 20 years. This success led to the development for borehole screens which have proven themselves in field trials which compared performance with imported stainless steel wedge wire screens. Some other proven applications have been pressure relief wells for several large state owned earth embankment dams in South Africa and Namibia and for leak detectors, environmental clean up and rehabilitation, water intakes and production boreholes.

Soloflo®’s proven wedge design opening borehole screens and drainage pipes are an engineered solution for Water Wells, Construction Expedients, Subsoil Drains and Environmental Applications. This promotes a long term solution which becomes very cost effective by removing the need for maintenance and replacement. This makes the client or end user happy.

Features and benefits


Soloflo screens are made from  ABS  = Acrylonitrile Butadiene Styrene which is a  virgin high impact grade polymer.

Parallel Outer Fins

The Parallel Outer Fins enhance compressive strength underground, promote radial and laminar flow, reduce energy loss, protect the wedge shape openings.


Extends service life, performance, minimises biofouling and eliminates water quality constraints in all applications.


Using proven wedge opening technology for the applications engineer.


Meeting long term service and performance goals to achieving lower unit costs with an extended life-time


Non-tainting and non-toxic products


Soloflo® wedge opening screens are easy to assemble on-site with flush threaded inside diameter (ID) & outside diameter (OD) joints.

The flush OD prevents bridging of gravel filter packs during placement. The flush ID does not restrict development tools and other equipment.

Product Evolution

Generation 1: Cut slots in plastic and steel

Twisting and turning of elongated particles can clog parallel openings. Water flow is excessively turbulent at the entrance to the slot, causing enegy loss which can cause chemical reactions through the release of gases.This causes excessive drawdown. The nett results are higher pumping and maintenance costs above and below ground.

Generation 2: Wedge wire steel wrapped screens

Only two points of contact occur at the inlet to the screen. If the elongated particles can pass through the inlet, this wedge shaped opening creates no restriction as the particles turn which assists the development process.

Generation 3: Soloflo® Wedge Opening Screens

Wedge opening screens promote the development of the reverse filter, reduce drawdown and are also proven to be resistant to clogging

Wedge Opening sizes

A soil grading would be ideal to assist in choosing the correct wedge opening size.

Flow Rates

The following optimal flow rates assume a velocity of not more than 0.03 m per second as recommended by Johnson Filtration Systems Inc. Using 0.03 m per second, the optimal flow rate per metre of screen to be expected would be:

  150mm Screen ID Percentage of open area Litres per second Litres per hour
  0.25mm Opening 2,67% 0.40 1 462
  0.50mm Opening 5,32% 0.81 2 925
  0.75mm Opening 7,98% 1.22 4 388
  1.00mm Opening 10,64% 1.62 5 850
  200mm Screen ID Percentage of open area Litres per second Litres per hour
  0.25mm Opening 2,42% 0.48 1 741
  0.50mm Opening 4,84% 0.97 3 482
  0.75mm Opening 7,27% 1.45 5 231
  1.00mm Opening 9,69% 1.94 6 972

These optimal flow rates need to consider the characteristics of the aquifer whereby these flow rates will be determined further by, amongst other things:
1. The available head of the aquifer.
2. Transmissivity of the aquifer.
3. Thickness of the aquifer.

Keywords: Pressure Relief, Screens, Wedge Opening