Grout Pump

Overview

A grout pump is a positive-displacement piston pump mounted on a self-contained skid with a Mixer Tank Assembly, a hydraulic drive, hose reel, and controls. It meters flowable grout from the tank into a delivery hose under pressure, typically 20–80 bar depending on grout viscosity and line distance. The operator controls discharge pressure and flow rate, adjusting for soil conditions, hole depth, and viscosity changes as grout sets.

The pump is essential for deep foundation anchoring, dam grouting, and soil stabilization where controlled placement and pressure are critical. Unlike concrete pumps that push large volumes, grout pumps are designed for precision at lower flow rates over long distances, often hundreds of metres vertically or horizontally.

How it works

The Diesel Engine, a compact turbodiesel, idles on the skid and drives a main hydraulic pump that supplies pressurized oil to the Hydraulic Motor. This motor, through a crankshaft linkage, reciprocates the Piston Rod in the pump Pump Casting at rates of 20–60 cycles per minute.

On the intake stroke, the piston draws grout from the Pump Suction Port submerged in the Mixer Tank Assembly. The Check Valve intake check opens to admit grout. On the discharge stroke, the piston pushes grout forward, the intake check slams shut, and the discharge check opens to force grout through the Pressure Hose to the Hose Reel Assembly and out into the borehole or grout line.

The Mixer Tank Assembly continuously stirs the grout slurry with the Mixer Paddle & Drive paddle, preventing coarse particles from settling and clogging the pump. The paddle shaft turns at 20–60 rpm, gently folding the material. If grout sits too long without mixing, it can set and lock the pump solid, so the agitator runs continuously during and between pumping intervals.

Pressure control is handled by the Relief Valve, an adjustable relief that vents excess flow back to tank once the pressure limit is reached. The operator adjusts this limit via a lever or screw, watching the Pressure Gauge and Flow Meter to match grout viscosity and delivery conditions. Thicker grout requires higher pressure; runny pre-grouted sand requires lower pressure to avoid breaking the hole wall.

The Hose Reel Assembly stores 100–500 metres of reinforced hose. Some reels are powered to auto-feed hose; most are hand-cranked or allowed to unwind as grout flows. The discharge hose ends in a Hose Guide & Swivel, a swivel union that allows the hose to rotate freely without twisting the reel or tangling.

All hydraulic circuits feed from the engine-driven main pump in the Hydraulic Drive System, a simple circuit with minimal filtration, grout is abrasive and clogs fine mesh, so coarse strainers are common. The system is rugged and slow; a piston pump running at 1,500 rpm is gentle enough not to foam or degrade the grout.