Pump Bypass Valve Control for Minimum Refrigerant Flow
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Solution Overview
Problem
Centrifugal pumps in refrigeration systems require a continuous minimum flow-through rate to maintain stability, leading to inefficiencies and increased costs due to the need for pumps with higher capacities than necessary, as well as larger primary flow lines, which are not optimally utilized when refrigerant load requirements vary.
Innovation Solution
A bypass control apparatus comprising a bypass flow line, a bypass valve, and a controller that determines the existing flow-through rate and adjusts the bypass valve to either allow or prevent fluid circulation from the discharge to the suction side of the pump, ensuring a predetermined flow-through rate is maintained, thereby optimizing pump capacity and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pump with higher capacity is selected to meet maximum refrigerant load requirements, then the pump can handle peak demand, but the pump operates inefficiently at low loads and requires larger primary flow lines that are not optimally utilized
Solution Approach 1:
The patent applies dynamics by making the bypass valve adjustable to dynamically change the bypass flow rate. This allows the system to adapt the pump's effective operating point in real-time based on refrigerant load requirements, enabling the pump to operate efficiently across a range of conditions rather than being fixed at a single operating point
Solution Approach 2:
The patent changes the flow rate parameter through the bypass line by adjusting the bypass valve. This parameter change effectively modifies the pump's operating characteristics, allowing the same pump to deliver different flow rates efficiently depending on the bypass setting, thereby resolving the contradiction between handling peak demand and operating efficiently at low loads
2Reliability
If a fixed orifice or manually adjustable valve is used in the bypass flow line to set minimum flow-through rate, then the pump maintains stable operation, but the system lacks flexibility to optimize for varying refrigerant load requirements
Solution Approach 1:
The patent replaces static flow control devices (fixed orifice, manual valve) with a dynamic electronic control system that includes a controller and an adjustable bypass valve. This dynamic system can continuously adapt the bypass flow rate based on real-time refrigerant load conditions, maintaining pump stability while providing the flexibility needed for varying operational demands
Solution Approach 2:
The patent implements feedback control by using sensors to detect refrigerant flow rate or pump operating conditions and feeding this information back to the controller. The controller then adjusts the bypass valve position accordingly, creating a closed-loop system that automatically maintains optimal pump operation across varying loads without manual intervention
3Productivity
If the bypass flow line is sized for maximum flow requirements, then the system can handle peak loads, but the primary flow lines and pump are oversized for typical operating conditions
Solution Approach 1:
The patent uses dynamic bypass valve control to redirect excess flow through the bypass line when operating below peak capacity. This allows the system to maintain the physical infrastructure sized for peak loads while dynamically managing the actual flow distribution to match current demands, preventing energy waste from running oversized pumps and flow lines at partial capacity
Data Source
AI summary
A bypass control apparatus is used with a pump pumping a fluid therethrough. A bypass flow line circulates fluid about the pump. A bypass valve is interposed in the bypass flow line and moves between an opened state to permit the fluid to circulate through the bypass flow line back to the pump and a closed state to prevent the fluid from circulating through the bypass flow line. A sensor determines an existing flow-through rate of the fluid flowing through the pump. The controller communicates with the sensor and the bypass valve and moves the bypass valve to the closed state when determined that the existing flow-through rate of the fluid through the pump is at least a predetermined flow-through rate and moves the bypass valve to the opened state when determined that the existing flow-through rate of the fluid through the pump is less than the predetermined flow-through rate.