Taking the flow rate from 6000 L/h up to 18000 L/h, the proposal that is heard most easily is to fit a bigger pump. Carried through to the end, however, that line of thinking shows that the pump only solves the problem of whether the machine can draw the oil at all; what really decides whether the machine can keep delivering oil is a number of other sections that have to be scaled up as well.
The pump set: the pumping speed and the power have to be scaled up together
The ZYD-100 has a flow rate of 6000 L/h, the ZYD-200 12000 L/h and the ZYD-300 18000 L/h. Three times the flow rate means that three times the oil has to be pushed in and out within the same time. If the pumping capacity is not scaled up with it, the first symptom is often not an alarm but the working vacuum dropping out of the -0.08 ~ -0.0999 MPa range, with the degassing efficiency falling accordingly. The pumping speed and the power of the combination of the X-100 rotary vane pump and the JRP-500 Roots pump have to be recalculated for the new oil throughput.
Pipe diameter: once the velocity rises the pressure loss goes with the square
If the pipe diameter is not scaled up, the velocity of the same pump in the same line rises several times over. The pressure loss in the pipework is proportional to the square of the velocity, and the result is that a large part of the head of the pump is spent in the pipework, while the pressure actually available to push the oil into the tank becomes smaller. What is seen on site is pressure at the pump outlet with no oil rising in the tank, or a flow rate that drops on its own once the oil temperature rises. When the flow rate is scaled up, therefore, the pipe diameter, the number of bends and the routing of the line have to be changed as one group, not added afterwards once the flow has fallen.
The filtration area and the number of filter elements
Filtration is the section of this equipment where the bottleneck appears first. The standard configuration of the ZYD-100 is 5 × 150-500-5 fine filter elements in parallel, with a filtration accuracy of ≤1 μm, and the treated oil has a cleanliness of NAS 1638 class 5, a water content of ≤3 ppm (GB/T 7600), a gas content of ≤0.01% (GB/T 423) and a breakdown voltage of ≥65 kV (GB/T 507). These figures hold at the rated throughput. If the flow rate is tripled while the filtration area stays the same, the differential pressure across the elements climbs at a rate that is visible to the eye, the dirt holding capacity is used up quickly, and whether the figures can be held becomes a matter of luck.
- Pump set: recalculate the pumping speed and the power for the new oil throughput, so that the negative pressure does not collapse during continuous feeding.
- Pipework: scale up the diameter and the routing at the same time, so that the pressure loss does not eat up the head and the flow does not fall on its own once the oil is heated.
- Filtration: increase the filtration area and the number of elements in proportion to the flow rate, so that the rate of rise in the differential pressure stays the same.
- Tank and thermal load: scale up the effective volume of the tank, the heating power and the heat dissipation capacity together, so that the temperature control is stable.
Tank volume and thermal load
Far-infrared carbon fibre heating is responsible for holding the oil temperature inside the set range. Once the flow rate is scaled up, the amount of oil passing through per unit of time is three times what it was, and the heating power, the effective volume of the tank and the heat dissipation area all have to be calculated accordingly. Increasing the power without increasing the tank means the oil is drawn off before it has been heated evenly and the temperature field stays disordered; increasing the tank without increasing the power means the heat-up time is multiplied and the time the site spends waiting for the oil is longer.
| Section | ZYD-100 baseline | Scaled up to 12000 / 18000 L/h | What to check on acceptance |
|---|---|---|---|
| Flow rate | 6000 L/h | 12000 L/h, 18000 L/h | The steady flow rate during continuous feeding |
| Pump set | X-100 rotary vane pump with the JRP-500 Roots pump | Pumping speed and power scaled up with the flow rate | Whether the negative pressure is steady at -0.08 ~ -0.0999 MPa |
| Filtration | 5 × 150-500-5 fine filter elements in parallel | Filtration area and number of elements increased at the same time | The rate of rise in the differential pressure and the cleanliness at the outlet |
| Tank and heating | Far-infrared carbon fibre heating | Effective volume, heating power and heat dissipation scaled up together | The stability of the temperature control and the heat-up time |
Scaling up the flow rate is four sections moving together, not a matter of fitting a bigger pump; if any one of them does not keep up, it will finally show up as a vacuum level or an outlet figure that does not meet the requirement.