ZX / ZXL Self-priming Centrifugal Pump

ZX / ZXL Self-priming Centrifugal Pump

ZX/ZXL Horizontal Self-Priming Centrifugal Pump | Fast priming for clean-water transfer

  • Self-priming: Quick priming for suction-lift duty.
  • Clean-water service: For clean water and similar liquids.
  • Stable running: Smooth operation with low vibration/noise.
  • Easy maintenance: Service-friendly structure with standard wear parts.
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Product Overview 

The ZX Self-Priming Centrifugal Clean Water Pump is a compact, self-priming centrifugal pump that is simple to operate, stable in performance, and easy to maintain. It offers high efficiency, long service life, and strong self-priming capability. No foot valve is required; simply store a certain amount of start-up liquid in the pump body before starting. This simplifies the pipeline system and improves operating conditions.

Model Designation

ZX ZXL Self priming Centrifugal Pump type 1

Key Features 

  • Strong Self-Priming Capability: No foot valve is required; the pump can start by retaining start-up liquid inside the pump.

  • Compact Structure: Simple operation, smooth performance, and easy maintenance.

  • Wide Fluid Compatibility: Handles clean water, seawater, mild acidic/alkaline liquids, and general slurry (viscosity ≤100 cP, solid content ≤30%).

  • Self-Priming Mechanism: Uses a gas-liquid mixing, separation, and circulation process to ensure continuous self-priming until all air in the suction pipe is expelled.

Engineering Overview 

The ZX self-priming pump uses an axial circulation self-priming pump design. The pump body consists of a suction chamber, membrane liquid chamber, cylindrical chamber, circulation hole, and gas-liquid separation chamber. After startup, the impeller mixes the stored liquid with air from the suction pipe. Under centrifugal force, a liquid ring is formed and enters the gas-liquid separation chamber through the diffuser. The gas separates and is expelled through the outlet, and the liquid returns to the intake chamber. The process continues until all the air in the suction pipe is expelled, completing the self-priming process.

Typical Applications 

The ZX self-priming centrifugal clean water pump is widely used in:

  • Municipal environmental protection projects

  • Building services and firefighting systems

  • Chemical, pharmaceutical, electroplating, paper, petroleum, mining industries

  • Equipment cooling systems and oil tanker unloading operations

  • Agricultural irrigation systems (when equipped with spray devices)

  • Filter press systems for slurry transport

This pump is suitable for clean water, seawater, mild acidic/alkaline liquids, and general slurry (viscosity ≤100 cP, solid content ≤30%).

System Configuration

The ZX self-priming pump consists of the following components:

  • Pump Casing: Suction chamber, liquid storage tank, pump casing, circulation hole, and gas-liquid separation chamber.

  • Rotating Assembly: Impeller, pump shaft, shaft sleeve.

  • Sealing System: Front and rear sealing rings to prevent leakage between high-pressure and low-pressure areas.

  • Bearing Assembly: Rolling bearings with lubrication to ensure smooth, low-noise operation.

  • Cooling Function (for some models): Cooling chamber inside the bearing casing, with an external cooling liquid inlet for temperature control.

Technical Service

Operating Conditions 

  • Start-up Requirement: Ensure that a certain amount of start-up liquid is stored in the pump body before starting.

  • Pipeline Requirement: No foot valve is required in the suction pipe.

  • Applicable Fluids: Clean water, seawater, mild acidic/alkaline liquids, and general slurry (viscosity ≤100 cP, solid content ≤30%).

  • Cooling Requirement: If the pump casing temperature exceeds 70°C, cooling liquid should be circulated through the cooling inlet to reduce the temperature.

  • Wearing Parts Maintenance: If the wear rings start to affect efficiency or self-priming performance, they should be replaced.

Service Conditions 

  • Applicable Fluids: Clean water or liquids with similar properties to water.

  • Solid Content: Maximum particle size ≤2 mm (by volume).

  • Liquid Temperature: -15°C to +80°C (maximum operating temperature 80°C).

  • Maximum System Operating Pressure: ≤3.0 MPa (suction pressure + pump operating pressure).

  • Ambient Temperature: ≤40°C.

  • Relative Humidity: ≤95%.

Protection Features

  • Self-Priming Ability: Ensures reliable self-priming through optimized gas-liquid separation technology.

  • Temperature Monitoring: Optional external cooling water system helps maintain the bearing temperature within a safe range.

Selection Standards 

The pump selection should be based on the actual application requirements, including fluid type, flow rate, operating pressure, and temperature requirements. Ensure the proper selection of seal types and cooling solutions to guarantee the pump’s long-term stable operation.

Installation & Dimensions

Outline Drawing

ZX ZXL Self priming Centrifugal Pump type jiegoutu

Performance Data

1 Coupling 2 Pump Shaft 3 Bearing 4 Mechanical Seal 5 Bearing Housing 6 Pump Casing 7 Outlet Seat
8 Inlet Seat 9 Front Wear Ring 10 Impeller 11 Rear Cover 12 Water-Blocking Ring 13 Filling Port 14 Recirculation Port

Performance Parameters

Model
Inlet
Outlet
Suction Lift
Motor Power
Flow Rate
Head
(mm)
(mm)
(m)
(kW)
(L/min)
(m)
25ZX3.2-20
25
25
6.5
0.75
3.2
20
25ZX3.2-32
25
25
6.5
1.1
3.2
32
40ZX6.3-20
40
32
6.5
1.1
6.3
20
40ZX10-40
40
40
6.5
4
10
40
50ZX15-12
50
50
6.5
1.5
15
12
50ZX18-20
50
50
6.5
2.2
18
20
50ZX12.5-32
50
50
6.5
3
12.5
32
50ZX20-30
50
50
6.5
4
20
30
50ZX14-35
50
50
6.5
4
14
35
50ZX10-40
50
50
6.5
4
10
40
50ZX12.5-50
50
50
6.5
5.5
12.5
50
50ZX15-60
50
50
6.5
7.5
15
60
50ZX20-75
50
50
6.5
11
20
75
Model
Inlet
Outlet
Suction Lift
Motor Power
Flow Rate
Head
(mm)
(mm)
(m)
(kW)
(L/min)
(m)
65ZX30-15
65
50
6.5
3
30
15
65ZX25-32
65
50
6
5.5
25
32
80ZX35-13
80
80
6
2.2
35
13
80ZX43-17
80
80
6
4
43
17
80ZX40-22
80
80
6
5.5
40
22
80ZX50-25
80
80
6
7.5
50
25
80ZX50-32
80
80
6
7.5
50
32
80ZX60-55
80
80
6
18.5
60
55
80ZX60-70
80
80
6
22
60
70
100ZX100-20
100
80
6
11
100
20
100ZX100-40
100
100
6
18.5
100
40
100ZX100-65
100
100
6
30
100
65
100ZX70-75
100
100
6
30
70
75
Model
Inlet
Outlet
Suction Lift
Motor Power
Flow Rate
Head
(mm)
(mm)
(m)
(kW)
(L/min)
(m)
150ZX170-55
150
150
5
45
170
55
150ZX170-65
150
150
5
55
170
65
150ZX160-80
150
150
5
55
160
80
200ZX400-32
200
200
5
55
400
32
200ZX280-63
200
200
5
90
280
63
200ZX350-65
200
200
5
110
350
65
250ZX550-32
250
250
5
75
550
32
250ZX400-50
250
250
5
90
400
50
250ZX450-55
250
250
5
110
450
55
250ZX400-75
250
250
5
132
400
75
300ZX600-32
300
300
5
90
600
32
300ZX500-50
300
300
5
110
500
50
300ZX550-55
300
300
5
132
550
55

Operating Manual

Installation

When the pump and motor are directly coupled, pay attention to the concentricity between the pump shaft and the motor output shaft. Correct installation is crucial for smooth operation and long service life, so alignment must be performed carefully and accurately.

The pump coupling must be secured with bolts, and the nuts should be locked. Loose nuts can cause axial movement of the impeller, leading to mechanical failures.

To maintain a certain amount of liquid in the pump casing for good self-priming performance and to prevent dry running of the mechanical seal, the pump inlet should be installed above the pump shaft centerline.

Suction Pipeline Installation:

A. The installation height of the suction inlet should not exceed 3.5 meters. When possible, install the suction inlet as low as possible below the minimum liquid level in the sump, and keep the suction line as short as possible with fewer elbows. This helps shorten self-priming time and improve self-priming performance.

B. Valves, flanges, and other fittings in the suction line must be leak-free. Air leakage in the suction line is not acceptable.

C. Solid particles and debris must be prevented from entering the pump. A strainer should be installed on the suction pipeline. The effective open area of the strainer should be 2–3 times the cross-sectional area of the suction pipe, and the strainer should be inspected and cleaned regularly.

D. Both the suction and discharge pipelines must be supported by their own pipe supports. The pump casing must not bear the weight or stress of the pipelines.

During installation, the static grounding resistance of the pump and pipelines must meet the specified requirements.

Carefully check that the static grounding resistance of the pump casing and pipelines meets the specified requirements.

Align the coupling between the pump and the motor and check the installation clearance and concentricity. The allowable misalignment should be within 0.1 mm. The height difference between the pump shaft and the motor shaft can be adjusted by adding shims under the base.

After the unit has run for 3–4 hours, perform a final inspection. If no abnormalities are found, the installation is considered correct. During trial operation, check the bearing temperature; the bearing housing temperature should not exceed 70°C.

For pump bearing housings equipped with a cooling chamber, the cooling water connectors are designed for rubber or plastic hoses with an inner diameter of 12 mm, and the thread size is M12×1.25.

If a check valve is installed on the discharge pipeline and air cannot be discharged smoothly during self-priming, a small vent pipe and valve should be added at the pump outlet to exhaust air.

Operation

(I) Installation

This series of self-priming pumps uses high-quality calcium-based grease or No.10 machine oil for lubrication, depending on operating conditions. For pumps using grease lubrication, regularly add grease to the bearing housing. For pumps using oil lubrication, top up the oil if the level is insufficient.

Check whether the liquid level inside the pump casing is higher than the upper edge of the impeller. If not, fill the pump casing directly through the filling port. The pump must not be started with insufficient liquid; otherwise, it will not operate properly, and the mechanical seal may be damaged.

Check whether any rotating parts of the pump are rubbing or jamming.

Check whether the nuts on the pump base and all connection points are loose.

Check the concentricity and parallelism between the pump shaft and the motor shaft.

Check whether there is any air leakage in the suction pipeline. If leakage is found, it must be eliminated.

Open the suction valve and slightly open (do not fully open) the discharge control valve.

(II) Start-up and Running

Jog the motor to check whether the pump shaft rotates in the correct direction.

Pay attention to any abnormal noise or vibration during rotation.

Observe the readings of the pressure gauge and vacuum gauge. After start-up, when the readings fluctuate for a period of time and then stabilize, it indicates that the pump has been fully primed and has entered normal conveying operation.

During self-priming, pay special attention to the water temperature in the pump. If the self-priming time is too long, the water temperature may become too high. In this case, stop the pump and check for the cause.

If a high liquid temperature in the pump causes difficulty in self-priming, stop the pump temporarily and let the liquid in the discharge pipeline flow back into the pump, or add liquid directly through the filling port to reduce the temperature, then restart the pump.

If severe vibration and noise occur during operation, cavitation may be happening. Cavitation is usually caused by excessive suction flow velocity or excessive suction lift. When the flow velocity is too high, adjust the discharge control valve to increase the pressure at the pump outlet. If there is a blockage in the suction pipeline, remove it in time. If the suction lift is too high, lower the installation height of the pump appropriately.

If the pump is stopped during operation and needs to be restarted, slightly open (do not fully close) the discharge control valve before start-up. This helps exhaust air during self-priming and allows the pump to start under a lighter load.

(III) Pump Shutdown

First, close the gate valve on the discharge pipeline.

Stop the pump.

In cold seasons, drain the liquid from the pump casing and the cooling chamber in the bearing housing to prevent damage caused by freezing.

OEM & Custom

We offer OEM/ODM manufacturing including material selection (cast iron or stainless steel), voltage (220V/380V/415V), and flange standards (DIN, ANSI, JIS). Optional control panels, baseplates, and explosion-proof motors are available. All pumps are ISO9001 and CE certified for global export.

FAQs

  1. Q: What is the difference between ZX and ZXL models?
    A: ZX uses cast iron for clean water, while ZXL uses stainless steel for light corrosive liquids.
  2. Q: What’s the maximum suction height?
    A: Up to 6 meters under proper installation and sealing conditions.
  3. Q: Can the pump handle corrosive media?
    A: Yes, ZXL models with stainless steel construction can handle weak acids or alkalis.
  4. Q: What’s the maximum temperature?
    A: 80°C for standard models; special configurations available on request.
  5. Q: Is the pump suitable for firefighting systems?
    A: Yes, it can be used for firefighting water supply and emergency systems.
  6. Q: Do you offer OEM branding?
    A: Yes, private labeling and packaging customization are available for export clients.
  7. Q: What certifications are provided?
    A: All SEAPUMP products are ISO9001 and CE certified to meet international standards.