SZP Series Slurry Pump — Bimetallic Construction for Abrasive Duty

SZP series slurry pumps use an inner and outer bimetallic construction — a ductile cast iron outer shell carrying the pressure, with a high-chrome anti-wear iron or rubber inner shell taking the wear. The two jobs are separated, so only the worn element is renewed.

• Single-stage, single-suction centrifugal; discharge sizes 40 to 300 mm
• Impeller with 3 to 6 twisted vanes and 8 back vanes on each shroud
• Bimetallic construction — ductile iron outer shell, high-chrome or rubber inner
• Solids concentration by weight: ash and coal slurry to 45 %, mineral slurry to 60 %
• Three shaft seal types: expeller plus packing, packing, or mechanical seal
• Cast iron, high-chrome alloy and rubber wet ends available

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CE · EAC · ISO 9001 · ISO 14001 · ISO 45001

Where the SZP Series Is Used

The series carries slurry with solid particles across heavy industry — power generation, metallurgy, coal, building materials and chemicals.

• Hydraulic ash removal in thermal power plants.
• Slurry transport in metallurgical ore dressing plants.
• Coal slurry and heavy medium transport in coal washing plants.
• Building materials and general abrasive transfer duty.

Bimetallic Construction

The hydraulic and structural design cuts power consumption by roughly 5 % against conventional slurry pumps on the same duty.

The pump separates two functions that a single-shell pump has to combine. The outer shell is ductile cast iron and carries the pressure. The inner shell is high-chrome anti-wear cast iron or rubber and takes the abrasion.

Because the wear element is a separate part, renewing it does not mean renewing the pressure casing — which is what keeps the cost of ownership down on a duty that consumes wear parts continuously.

Working Conditions

Construction in Detail

The outer shell is cast in HT200 grey iron or QT500-7 ductile iron according to working pressure. The inner shell — volute, front liner and rear liner — is cast in high-chrome alloy iron, or moulded in rubber as a front and rear volute pair. Only the inner shell is renewed as it wears.

The impeller carries twisted vanes, normally three to six, with eight back vanes on the outside of each shroud to cut recirculation and leakage. It is cast in high-chrome alloy iron and screwed onto the shaft. Discharge orientation is adjustable at 45° intervals through eight positions.

Shaft Sealing

Three arrangements are offered, selected against the duty:

• Expeller and packing combination — stuffing box, expeller, lantern ring, packing, gland and shaft sleeve.
• Packing seal — stuffing box, spacer sleeve, lantern ring, packing, gland and shaft sleeve. Needs a gland water supply.
• Mechanical seal — balanced double-face type, supplied assembled and pre-set in the stuffing box, with cooling water connections and a pressure gauge. Gland water must be running before start-up and for three minutes after shutdown.

Bracket and Lubrication

Two bracket forms are built. The split bracket is available with oil-bath or grease lubrication; the oil-bath version uses N32 oil in winter and N46 in summer. Sizes 150SZP and above carry a water-cooling jacket on the oil bath. The barrel bracket is grease lubricated only, using lithium grease No. 2 or 3, and is built for 200SZP and smaller.

Running limits from the manual: bearing temperature rise 35 °C, absolute maximum 75 °C; oil changed after 800 running hours; impeller-to-front-liner clearance held between 0.75 and 1.00 mm and reset as wear opens it up.

Model Performance Data

Clear-water performance for the models below. Ratings are per speed; three duty points are shown for each. Other sizes in the range are available — send your duty point and we will issue the matching curve.

Selecting Against the Duty

1. Start from the solids. Concentration and particle size decide the wear material before the duty point does.
2. Then the material. High-chrome alloy for coarse angular solids; rubber for fine rounded solids at high concentration; cast iron where abrasion is mild.
3. Then the duty point. Flow and head become meaningful once the first two are fixed.
4. Check the bracket type. Split brackets take oil-bath or grease lubrication; barrel brackets are grease only and cover 200SZP and smaller. Sizes 150SZP and above carry a water-cooling jacket.

What to Send With Your Enquiry

Send the flow and head, the slurry analysis with solids concentration by weight and particle size, the medium temperature and the pH. We will confirm the model and the wet-end material, and issue the performance curve with the quotation.

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