Three enclosure structures change three things about the same machine
When selecting an oil purifier, flow rate and accuracy are usually the first questions. The second question often comes up only in the latter half of a technical discussion: where will this unit be installed, and what weather will it work in over long periods. The three enclosure structures — open type, canopy type and fully enclosed — do not decide what the machine can do; they decide under which conditions it can run continuously, whether maintenance staff can stand in front of the unit, and whether cleanliness can be maintained.
The first thing is rain protection. When oil pipe fittings, terminal blocks and filter element end caps stay exposed year-round, rainwater runs down the columns and then seeps into the seams from the outside. The consequence is not only corrosion but premature ageing of the seals and moisture in the insulating components. Neither of these triggers an alarm directly; they show up in other ways: once the seals harden, slow air leakage on the vacuum side becomes more likely.
The second thing is dust protection. When dust settles on the equipment, in the ambient temperature range of -20–45 °C, dust mixed with oil mist forms an adhering layer on the inner walls of the electrical cabinet and on the heat sinks, the heat cannot be dissipated and the temperature inside the cabinet rises. A unit with a total power of 72 + 5 kW may, under these conditions, trip on protection precisely because of insufficient heat dissipation. The actual service life of seals and electrical components is shortened in such an environment.
The third thing is accessibility for maintenance. Whether the cabinet doors can be opened as a whole, and whether maintenance staff can stand facing the unit while changing elements, directly determine how long one element change takes. The enclosure protects the equipment, but the price is often reduced maintenance space, and the loss in efficiency when people work squeezed into a confined position can outweigh the benefit of the upgraded protection.
Size determines handling, and the enclosure structure amplifies this constraint
Take ZYD-100 as an example: overall dimensions 1200×1400×1800 mm, equipment weight approx. 720 kg. This size means two things: first, it cannot be carried by an ordinary hand cart, and second, it has to pass through a doorway the right way round. The 1200 mm corresponds to the width of the cabinet including the outer frame, and the 1800 mm corresponds to the height of the tank plus the top piping. The clear width and clear height of doorways and goods lifts must both be checked against these dimensions, and if no margin is left, it will not go through.
The enclosure structure is not neutral in this respect. A fully enclosed unit also needs clearance outside for the door swing; if the cabinet door opens outwards as a whole, there must additionally be space for a person to stand on the opening side. A canopy type unit adds a roof and columns, so on the same site it occupies a larger floor area than an open type unit. This calculation has to be made on the usable site area, not on the footprint of the machine itself.
The handling difficulty caused by weight is not solved by the enclosure, but it is amplified by it. An open type unit has no door frame constraint, so components can be lifted in sections; a fully enclosed unit is a single integral cabinet and can only be delivered to site as a whole. This is where the value of mobile selection lies: TYG-100 is a 6000 L/h mobile vacuum oil purifier, and the point of mobility is to pull it to the position where the work has to be done.
Correspondence between environmental conditions and enclosure structure
The temperature range of -20–45 °C marks the environmental limits of the equipment. On the low-temperature side, outdoor placement raises the viscosity of the oil and increases the start-up resistance; the upper limit of 45 °C corresponds to the difficulty of controlling the oil temperature. Here the enclosure acts as a buffer and not as a modifier: a canopy type blocks direct sunlight and rain, a fully enclosed unit can also keep ambient wind out, so the temperature control setting of 45–80 °C is easier to keep stable, the oil temperature fluctuates less, and the efficiency of the degassing stage is more consistent.
Altitude affects the vacuum level. This has no direct relation to the enclosure form, but it means that temperature alone is not enough when selecting a unit. Writing the installation location and the altitude into the technical requirements, together with the delivery of the equipment to the plant, is less trouble than finding a solution once the equipment has arrived on site. Only by checking the ambient temperature and the altitude together can it be established whether the conditions at the target site fall within the applicable range.
When a structural upgrade is not worthwhile
The most common waste is making equipment that is permanently installed inside a workshop into a fully enclosed unit. Inside a workshop the unit is already protected from rain and direct sunlight, and an open type unit with a canopy added is enough to cover the operational requirements; one more layer of doors and sealing brings only a limited improvement, and every movable part added is one more potential leak point. The other case is temporary work, where the unit moves between several sites and the transport burden of a fully enclosed unit is markedly higher than that of an open type unit.
List the site conditions first, then choose the structure
| Site conditions | Structural preference | Consequence |
|---|---|---|
| Permanently outdoors, frequent rain | Start with canopy type | Electrical components and seals take up moisture |
| Outdoors with heavy dust | Fully enclosed | Dust accumulation raises the temperature inside the cabinet |
| Inside a workshop, fixed position | Open type | Lowest level of protection, best maintenance access |
| Frequent relocation between sites | Open type or mobile type | Transporting the complete cabinet increases the transport burden |
| Installation at high altitude | No form restriction, altitude listed separately | The attainable vacuum level changes accordingly |
- First determine where the unit will be placed in future: indoors, outdoors, or moved between sites with the vehicle. This single point determines all the trade-offs that follow.
- Write down the site temperature range and the altitude, check whether they fall within -20–45 °C, and state the high-altitude requirement separately.
- Measure the minimum clear width and clear height of doorways, goods lifts and maintenance access routes; the cabinet plus its door swing radius has to be included in the calculation.
- Confirm the maintenance method: working with the cabinet door opened from the front, or drawing the filter elements out from the side; the requirements on the door position differ.
- Determine whether the cleanliness requirement is already guaranteed by the upstream process. Where upstream coarse filtration and settling are present, the enclosure level can be reduced by one grade.
The enclosure structure does not solve processing capacity; it answers the question of under which conditions this unit can finish the job. List the site conditions first, then decide whether it is worth paying for conditions that cannot be seen.
