Grout pumps: pressure versus flow

Häny has made this choice visible in the data sheet: the same pump is supplied with three different pistons, and each of them has its own column in the table and its own curve in the chart.

Same pump, three pistons

ZMP 710 with 85, 105 or 120 mm piston diameter:

• 85 mm — 3.9 m³/h at max. 100 bar
• 105 mm — 5.5 m³/h at max. 68 bar
• 120 mm — 7.5 m³/h at max. 50 bar

The same curve, one size up

The ZMP 725 has a double pump module and the same three pistons, but considerably more flow:

• 85 mm — 5.9 m³/h at max. 100 bar
• 105 mm — 9 m³/h at max. 68 bar
• 120 mm — 11.7 m³/h at max. 50 bar

Single- or double-acting

The ZMP 725 is specified with a double pump module, while the pump in the IC 650/710 compact plant is single-acting. A double module gives more flow with the same pistons, as the figures above show. Of the single-acting ZMP 710, Häny writes that the suction stroke always runs at high speed, so that the pressure drop resembles that of a double-acting pump and is minimal.

The small pumps

Below the ZMP 700 series sits the ZMP 600 series, three pumps with a 65 mm piston and 0.82 litres per stroke:

• ZMP 610 — 1.5 m³/h, max. 100 bar, min. 3 bar, 5.5 kW, 270 kg
• ZMP 611 — 2 m³/h, max. 75 bar, min. 3 bar, 5.5 kW, 270 kg
• ZMP 625 — 2 m³/h, max. 100 bar, min. 3 bar, 5.5 kW

Minimum pressure is also a specification

If you are grouting at low pressure, it is the minimum pressure that sets the limit, not the maximum. The ZMP 725 is specified with 5, 4 and 3 bar as the minimum for the three pistons — and with the optional low-pressure control it goes down to 2, 1.5 and 1 bar. The ZMP 710 is specified with a minimum of 2, 1.5 and 1 bar, but Häny also writes that pressures as low as 1 bar can be preset with the low-pressure control valve.

It is worth clarifying this early, because the low-pressure control valve is an option.

Aggregate size

The ZMP 610, 611 and 625 take a max. aggregate size of 5 mm. The ZMP 710 and 725 take 8 mm. The series as a whole is specified at 5–8 mm. If you know what the mix contains, this is a quick way to rule pumps out.

When you really need to move a lot of material

The ZMP 820 is specified at 200 bar, but only 3.4 m³/h. If you need to move a lot of material, the triplex pump ZMP 936 is specified at up to 1 000 l/min — 60 m³/h — at 40 bar, and 121 kW. Here, it is the flow that matters, not the pressure.

Logging can be ordered with the pump

The ZMP 725 has remote control and data logging of pressure and flow on its list of options, alongside the low-pressure control valve and choice of piston unit. If the grouting has to be documented, it is worth including in the order.