When most projects compare a domestic oil purifier against an imported one during the enquiry stage, they compare the flow rate, the power and the price. Once the contract is signed it turns out that the time is actually spent on the interfaces, the spare parts and the parameters. The price difference on the machine itself is visible; the interface work, the shutdown window and the waiting for spare parts are not, and they are usually the larger part. Checking those three lines before the swap is what turns a replacement into a replacement rather than a modification.
Establish the scope of the swap first
Start by establishing whether the whole machine is being replaced or only part of the system. Swapping the degassing unit and keeping the existing filtration is a different job from swapping the whole machine, with a different number of interfaces and a different effect on the process. The existing conditions that can still be used also have to be listed first: the oil tank, the heating system, the route of the pipework, the capacity of the supply, the position of the distribution board and the foundation. These are the most valuable part of a replacement and the part most easily left out, because they do not appear on the quotation but they decide how long the shutdown window has to be.
Interfaces: pipe diameter, flange and voltage are different things
The interfaces fall into three kinds: oil pipework, electrical and mechanical installation. For the oil side, check the pipe diameter and the flange standard, because a conversion between standards needs transition pieces, and enough straight pipe has to be kept before and after the transition; adding two elbows on the spot makes the flow resistance clearly worse. For the electrical side, confirm the supply system and the voltage level. The supply of the machine is three-phase 380V, 50Hz, so if the original system is three-phase 400V or a different frequency, the supply side has to be adjusted. For the mechanical side, the dimensions of the ZYD-100 are 1200×1400×1800 mm and the weight is approx. 720 kg, so the foundation, the lifting route and the door opening all have to be checked against the real figures rather than against the model name.
Spares: what to do when the part numbers do not match
The spares are harder to sort out than the machine itself, and filter elements are the typical case. The element specification system of an imported machine is different from ours: if the dimensions, the filtration accuracy or the thread of the connection differ in any one respect, the element cannot be fitted directly. The elements commonly used on our machines are the coarse elements 150-250-50 and 110-250-50, the second stage 110-400-20 and the fine elements 110-600-5 and 150-500-5, of which 150-500-5 is the standard configuration of the ZYD-100 with 5 elements in parallel. Going through the specification of the new machine against the specification actually in use on the old one before the swap saves a good deal more time than waiting for parts afterwards.
Parameters: the same nominal size does not mean the same duty
Lastly, compare the duty parameters. The same 6000 L/h flow gives different treatment results under different oil types, different oil temperatures and different vacuum levels. To see whether the terms are the same, look at three figures: the working vacuum range, the heating temperature control range and the filtration accuracy. The working vacuum of the ZYD-100 is -0.08 ~ -0.0999 MPa, the ultimate vacuum is ≤5 Pa and the filtration accuracy is ≤1 μm, with a water content after purification 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). Putting those figures next to the acceptance record of the machine that was there before is what tells you whether the new machine holds the original level or has to meet a different requirement.
| Item to check | What to compare | How to handle a difference | What it affects |
|---|---|---|---|
| Oil pipe connections | Pipe diameter, flange standard, length of straight pipe | Fit transition pieces and work out the resistance again | Length of the shutdown window |
| Electrical connections | Voltage level, frequency, power capacity | Adjust the supply side or choose a different configuration | Cost of the distribution work |
| Mechanical installation | Dimensions, weight, foundation and door opening | Adjust the foundation or the handling plan | The conditions for delivery on site |
| Spares specification | Element dimensions, accuracy, connection thread | Stock a first batch to the new specification | Waiting time during later shutdowns |
| Duty parameters | Working vacuum, temperature control range, filtration accuracy | Set the acceptance terms again on the basis of the figures | The acceptance conclusion |
- Copy the actual operating figures of the old machine; the figures on the nameplate are not enough.
- Stock the spares for the first batch in one go, and do not order elements against the old part numbers.
- Do the interface work in one shutdown window if at all possible; doing it in two costs more.
- Rebuild the baseline for the vacuuming time after the swap, because the volume and the pipework of the new machine are different.
A machine swap saves money on the machine itself and spends it on the time spent on interfaces and parts. Add up the last three items first and the account is a real one.
