In the world of industrial metering pumps, asphalt transfer has always been a "hot potato." When the customer is a research institution requiring extremely small volumes of asphalt with real-time flow display, the selection challenge multiplies.
Today, let's walk through a real customer case and see how the CIXIFM technical team solved this tricky problem.
A research institution needed a metering pump for asphalt transfer with the following specifications:
| Parameter | Requirement |
|---|---|
| Flow range | 80–120 L/H |
| Pressure | Approx. 0.5–0.7 bar |
| Asphalt temperature | 90–150°C |
| Viscosity at operating temp | 300–600 mm²/s |
| Flow measurement error | Within ±3% |
| Display requirement | Real-time L/H, at least 2 decimal places |
At first glance, the flow is modest and the pressure is low — seemingly not complicated. But the customer emphasized one critical challenge:
After each experiment, the asphalt cools to ambient temperature and must be reheated before the next experiment. Therefore, a flow meter is NOT a suitable solution.
This single statement eliminated the most common approach: metering pump + flow meter.
In conventional industrial settings, flow display is typically achieved through:
Metering Pump + Flow Meter + Display Instrument
But under asphalt conditions, this approach has fatal flaws:
Asphalt solidifies when cooled: Residual asphalt inside the flow meter pipes solidifies, clogging the meter and potentially damaging sensors.
Reheating is difficult: Flow meters have complex internal structures. Jacket heating cannot cover all dead corners, and uneven heating causes measurement distortion.
High cleaning and maintenance costs: The flow meter must be thoroughly cleaned after every experiment — a nightmare for researchers.
Precision is hard to guarantee: Viscosity changes dramatically with temperature, causing flow meter readings to drift. Maintaining ±3% accuracy consistently is nearly impossible.
So what the customer needed was not a "pump + flow meter" but a metering pump that inherently delivers precise measurement without an additional flow meter.
After consultation with our technical team, we recommended the following configuration:
| Configuration | Specification |
|---|---|
| Pump type | Plunger metering pump |
| Rated flow | 120 L/H |
| Rated pressure | 1.0 MPa |
| Inlet/Outlet | DN15 flange connection |
| Pump head | Full jacket heating |
| Motor | 0.75KW-4 standard motor |
| Pump head material | 304 stainless steel |
| Power supply | AC380V 50HZ 3PH |
1. Plunger design delivers high metering accuracy
A plunger metering pump achieves quantitative transfer through the reciprocating motion of a plunger. Each stroke has a fixed displacement, and flow is precisely controlled by adjusting stroke length or frequency. Under stable conditions, metering accuracy can reach ±1%, fully satisfying the customer's ±3% requirement.
2. Full jacket heating pump head — designed for asphalt
The pump head features full jacket heating, allowing steam, thermal oil, or hot water to circulate through it. This ensures asphalt maintains its 90–150°C operating temperature throughout the transfer process without solidifying. After the experiment, the jacket continues to provide heat, so the next experiment can start directly without disassembly or cleaning.
3. No flow meter needed — eliminating clogging risks
Flow is achieved through stroke adjustment and frequency control. The displayed value comes directly from the pump's operating parameters, not from a flow sensor inside the pipeline. This fundamentally avoids the problem of asphalt cooling and clogging the flow meter.
4. 304 stainless steel pump head — corrosion-resistant and easy to clean
The 304 stainless steel construction is suitable for asphalt and similar media. The smooth surface facilitates maintenance.
5. Flow display function can be integrated
Although not dependent on a flow meter, a stroke frequency signal + flow conversion module can be used to display real-time L/H on a screen with two decimal places, meeting the customer's monitoring requirements.
| Pump Type | Suitable? | Reason |
|---|---|---|
| Gear pump | ❌ | Asphalt solidifies when cooled — gears jam |
| Screw pump | ⚠️ | Moderate precision; flow display still requires a flow meter |
| Diaphragm pump | ⚠️ | High-temperature asphalt damages the diaphragm |
| Centrifugal pump | ❌ | Cannot meter precisely; flow fluctuates with pressure |
| Plunger metering pump | ✅ | High precision, heatable, no flow meter needed |
If you're also struggling with high-temperature, high-viscosity, easily solidifying media in micro-flow applications, here are some selection guidelines:
Prioritize metering pumps over "pump + flow meter": For media that solidify, the flow meter is the most failure-prone component.
The pump head must have a heating jacket: Ensure the medium stays above its flow temperature throughout the process.
Choose heat-resistant and corrosion-resistant materials: 304 or 316 stainless steel are common choices.
Flow display can be derived from pump parameters: No need to rely on inline flow meters.
For high precision, plunger type beats diaphragm type: Plunger pumps offer higher repeatability.
Asphalt metering pump selection may seem like a matter of flow and pressure, but it's really a comprehensive consideration of medium characteristics, process conditions, and maintenance costs. Especially in research settings, equipment must not only "work" but also be "user-friendly, durable, and hassle-free."
CIXIFM specializes in the selection and customization of industrial metering pumps and chemical metering pumps. If you have similar application requirements, feel free to contact us for a one-on-one technical solution.
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CIXIFM Winny
Email: [email protected]
WhatsApp: +86 18049841995
Whether it's asphalt, resin, grease, or other high-temperature, high-viscosity media, we can find the right metering solution for you.
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