Automated Gas Ballast Operation to Improve Oil Life
in Rotary Vane Vacuum Pumps

Industry
Pharmaceutical

Customer Concern
A pharmaceutical customer was using a rotary vane oil-sealed vacuum pump during
final product distillation. During the process, toluene vapours were coming out and
entering the oil vacuum pump.

These vapours were affecting the pump oil condition, resulting in faster oil
contamination, reduced vacuum performance, frequent oil changeover, and early
maintenance issues.

Although rotary vane oil vacuum pumps are generally provided with a gas ballast
arrangement, it is commonly operated manually. Due to manual dependency, the gas
ballast is often not used at the correct time or under the right operating condition,
leading to poor removal of low-boiling vapours from the pump oil.

Problem Observed Vovac Engineers studied the customer’s final product distillation process and observed that toluene vapours were entering the oil-sealed vacuum pump during operation.

The customer was facing:
● Toluene vapour carryover into the oil vacuum pump
● Frequent oil contamination
● Reduced oil life
● Frequent oil changeover requirement
● Early maintenance issues
● Vacuum performance drop due to contaminated oil
● Manual dependency for gas ballast operation
● Improper removal of low-boiling vapours from the pump
● Incoming vapours settling in the pump oil during cold start condition

Vovac Engineers’ Solution
Vovac Engineers introduced an automated gas ballast operation in the rotary vane
oil-sealed vacuum pump system. This helped remove toluene and other low-boiling
vapours from the pump more effectively during operation.

The automation was designed in such a way that when the pump starts, it does not
directly connect to the process. Instead, the pump is allowed to run in a blind condition for a defined period, allowing the pump oil temperature to gradually rise close to 80°C. Once the oil reaches the required operating condition, the pump is then connected to the process. This ensures that incoming toluene vapours do not immediately settle or condense in cold pump oil. Under vacuum and at the correct oil temperature, the low-boiling vapours can be removed more effectively from the pump through gas ballast operation. By automating this sequence, Vovac Engineers reduced manual dependency and improved the consistency of vapour removal from the pump.

The solution included:
● Automated gas ballast operation
● Initial blind running of pump before connecting to process
● Controlled oil heating up to approximately 80°C
● Delayed process connection to avoid toluene vapour settling in cold oil
● Effective removal of toluene and other low-boiling vapours from the pump
● Controlled operation based on pump/process condition
● Reduced manual intervention
● Improved oil life and pump reliability

Result Achieved
With automated gas ballast operation and controlled start-up logic, the pump was
protected from direct process vapour entry during cold start condition.
The initial blind running allowed the pump oil to reach the required temperature before exposure to process vapours. This helped prevent incoming toluene vapours from settling in the oil and improved their removal during vacuum operation.
As a result, the customer achieved improved oil condition, reduced oil contamination,
better oil changeover frequency, and reduced early maintenance issues.

Customer Benefit
● Improved handling of toluene vapours during final product distillation
● Improved oil life
● Reduced oil changeover frequency
● Lower maintenance requirement
● Better removal of low-boiling vapours
● Reduced vapour settling in pump oil during start-up
● Pump protected from direct cold-start process vapour exposure
● Reduced manual dependency
● Improved pump reliability
● More stable vacuum performance
● Lower operating and maintenance cost

Key Value Delivered
Vovac Engineers helped a pharmaceutical customer overcome oil contamination
caused by toluene vapour during final product distillation by introducing
automated gas ballast operation with controlled blind start-up. The pump was
allowed to heat the oil before process exposure, helping prevent incoming
vapours from settling in the oil, improving oil life, reducing oil changeover
frequency, and minimizing early maintenance issues.