Oil-Injected Compressor Temperature Control via Bypass Pipe
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Solution Overview
Problem
Oil-injected compressor devices with variable speed controllers face challenges in controlling temperature to prevent condensation and oil degradation, as existing methods either lead to energy loss or inadequate cooling when reducing flow rate, especially when using inlet throttle valves.
Innovation Solution
A method involving a bypass pipe across the oil cooler, where the fan or pump speed is adjusted or switched off when temperature drops, and oil is diverted through the bypass pipe or reduced injection when necessary, to gradually reduce cooling capacity and maintain optimal temperature, ensuring condensation prevention and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the speed of the compressor element is reduced to lower the flow rate, then the power absorption and heat generation are reduced, but the temperature control becomes difficult and condensation may occur
Solution Approach 1:
The invention changes the parameter being controlled from flow rate to temperature. The controller monitors temperature and adjusts the cooling system (bypass valve, cooler, fan/pump) based on temperature feedback, allowing the compressor to operate at low flow rates without condensation while maintaining proper temperature control
Solution Approach 2:
The invention implements a feedback control system where the temperature sensor continuously monitors the compressor element temperature and feeds this information back to the controller. The controller then adjusts the cooling system accordingly, creating a closed-loop control that prevents condensation even at reduced flow rates
2Productivity
If an inlet throttle valve is applied to reduce flow rate in a variable speed compressor, then the flow rate is reduced, but the temperature drops too low causing condensation
Solution Approach 1:
The invention introduces a bypass valve as an intermediary element that allows controlled mixing of cooled and uncooled oil. This bypass valve acts as a mediator between the cooler and the compressor element, enabling precise temperature control to prevent condensation while maintaining reduced flow rates
Solution Approach 2:
The invention shifts the control parameter from flow rate to temperature. By monitoring temperature and adjusting the cooling system accordingly, the system can operate at low flow rates without condensation, effectively changing what parameter is being actively controlled
3Temperature
If the fan or pump is kept running at constant speed to cool the oil, then the oil temperature is controlled, but energy is wasted when cooling is not required
Solution Approach 1:
The invention makes the cooling system dynamic by allowing the fan or pump speed to be adjusted based on actual cooling requirements. The controller varies the rotational speed of the fan or pump according to temperature feedback, enabling energy-efficient operation while maintaining proper oil temperature control
Solution Approach 2:
The invention changes the operating parameter of the fan/pump from constant speed to variable speed. By adjusting the rotational speed parameter based on temperature requirements, the system reduces energy consumption when full cooling capacity is not needed
4Object-affected harmful factors
If oil is diverted through the bypass pipe to prevent condensation, then condensation is prevented, but the lubrication quality may be compromised
Solution Approach 1:
The invention changes the control parameter from flow distribution to temperature. By controlling the bypass valve to maintain proper temperature rather than simply diverting oil flow, the system prevents condensation while ensuring adequate lubrication quality through temperature-controlled oil properties
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively prevents temperature drops and condensation, reduces energy consumption by adjusting cooling capacity first, and minimizes oil reduction to maintain lubrication, allowing for lower flow rates without detrimental consequences, while ensuring the temperature remains within safe limits.
Implementation Method 1
a cooler (18) in which the oil (15) can be cooled
Implementation Method 2
a fan (19) whose rotational speed can be varied, by which cooling air can be supplied to the cooler (18)
Data Source
Figure 1~2
AI summary
Method for controlling a compressor device (1) with a compressor element (2) and oil circuit (14) with oil (15) that is injected into the compressor element (2) by a fan (19) via a cooler (18), with a bypass pipe (20) across the cooler (18), whereby when the temperature (T) of the compressor element (2) is less than a value (Tset) the method consists of taking the following steps: - the fan (19) is switched off; - when the temperature (T) is still less than Tset, the oil (15) is driven via the bypass pipe (20); - when the temperature (T) is still less than Tset, the quantity of oil (15) that is injected into the compressor element (2) is decreased until the temperature (T) is equal to Tset.