Oil and Emulsion cooling plants

TRANSFER PUMP PLANT

The transfer pump plant is a preparatory (auxiliary) unit used in machine tools in the machining procedures such as: turning, milling, drilling, grinding, polishing, honing etc. for the purpose of supply of machine tools with oil and emulsions and other operating media of required properties. Since during the above machining procedures, the coolant mixes with the scraps resulting from the stock removal process and its heating, it is necessary to prepare the coolant for reuse, i.e. it is necessary to bring it into the shape suitable for its reuse with the same properties. The second task of this unit is direct supply of the machine tool with processed oils and emulsions required for the specific treatment procedure and their bringing into the treatment zone.

PLANT EXPLANATION

In the machining processes, it is necessary to recycle the liquids used as operating media, which is done by placing directly next to the machine a transfer pump unit which collects “dirty” oil and emulsions and transfers them to the central preparation unit which filters them, cools them and retransfers them to the transfer pump unit. The central preparation unit serves for the simultaneous preparation of operating media for all machine tools or only those for similar treatment procedures.
In view of the above functions, the transfer pump unit has two hydraulic rings with the supporting elements.
1.Ring - transfer of the so-called “dirty cooling medium” to the central unit. This ring consists of:
- pump which transports operating media to the central unit
- control valve of pipeline line
- manometer
- control valves
2.Ring - return of purified oil. This ring consists of:
- Pneumatically operated valves
- high pressure pump
- pressure switches
- working area rinse unit
- flow sensor
- safety valve etc.
The entire composition of the transfer pump unit is managed by a PLC, and it is equipped with the required electrical components such as:
  • level sensors (operating and safety)
  • foam sensor
  • flow meters etc.

The purpose of the return ring is to hold the purified and cooled oil, perform its additional filtration and convey it by the appropriate electrical or pneumatically operated valves to two rings:
The first ring is a low pressure ring which needs to supply the machine with the working area rinse medium by means of the appropriate cleaning guns. Another function enabled by the low pressure ring is bringing of the operating medium to the treatment zone for the purpose of reduction of friction and improvement of treatment parameters. The high pressure ring is directed to cooling the work piece during the honing procedure. Depending on the treatment procedure, in addition to the oil and emulsions, processing waste of various forms and sizes can appear at the collection unit. This is characteristic of treatment procedures in turning where the so-called turnings of larger lengths and diameters get into the tank, which as such are not suitable for transport to the central filtration unit. In that case, the transfer pump plant should be equipped with a unit for turnings breaking into the form and size suitable for transport to the central unit.

Other important functions that need to be fulfilled by this plant are:
  • Washing away of deposits of small processing waste from the internal walls of the tank and their directing to the sucking zone of the pump.
  • Process flow management: work cycles and tank liquid level control.
  • Work process self-management, i.e. detection of work interruption, its diagnostics and removal
  • Prevention of coolant loss and waste


The described system of renewal and management of the working fluid flows in treatment processes on machine tools provides an integral fulfilment of all its expected functions, from its transfer to the central unit, filtration, cooling, supply of machine with processed oil to an integral control of the functions and manner of operation.