Device for cool drying a gas
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Solution Overview
Problem
Existing cool drying devices for gases face inefficiencies in cooling capacity during unloaded states, leading to potential freezing and energy loss, with conventional pressure-controlled bypass valves resulting in suboptimal cooling and higher pressure dew points when loaded.
Innovation Solution
Reconnecting the control pressure pipe upstream of the evaporator outlet in the cooling circuit, potentially with an additional restrictor, to manage pressure and temperature dynamics, ensuring more intense cooling and reduced pressure dew point fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cooling capacity is increased to improve drying performance, then the drying efficiency is improved, but the risk of freezing in the evaporator increases
Solution Approach 1:
The bypass valve dynamically adjusts the coolant flow distribution between the evaporator and bypass line based on operating conditions. When the heat exchanger is heavily loaded, more coolant flows through the evaporator to maximize drying efficiency. When lightly loaded or unloaded, the bypass valve redirects coolant away from the evaporator to prevent freezing, thus adapting the cooling capacity to match the actual drying demand.
2Reliability
If the bypass valve is opened during unloaded state to prevent freezing, then the freezing risk is reduced, but energy is wasted due to continuous coolant circulation
Solution Approach 1:
The harmful effect of continuous full-capacity coolant circulation during unloaded states is extracted and redirected through the bypass line. The bypass valve separates the coolant flow into two paths: a reduced flow through the evaporator sufficient for preventing freezing, and a larger flow through the bypass line that returns to the compressor inlet, thereby eliminating unnecessary energy consumption while maintaining freezing protection.
3Ease of operation
If the control pressure is tapped downstream of the evaporator, then the bypass valve responds to evaporator pressure, but the pressure dew point is higher and cooling is less intense
Solution Approach 1:
The control pressure is tapped upstream of the evaporator, allowing the bypass valve to anticipate and respond to pressure changes before they occur in the evaporator. This preliminary control action enables the bypass valve to adjust coolant flow in advance, optimizing the pressure dew point and ensuring more intense cooling by maintaining better control over the evaporator operating conditions throughout load transitions.
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 configuration allows for more effective cooling of gases to a lower pressure dew point, reducing the risk of freezing and energy wastage, enabling better drying performance and potentially downsizing the exchanger while maintaining consistent dew points across varying loads.
Implementation Method 1
As a result of the evaporation of the coolant in the evaporator, or thus the primary part of the heat exchanger, as is known, heat is extracted from the gas to be dried flowing through the secondary part, whereby this gas to be dried is cooled
Implementation Method 2
As a result of the evaporation of the coolant in the evaporator, or thus the primary part of the heat exchanger, as is known, heat is extracted from the gas to be dried
Implementation Method 3
a condenser connected to an outlet of the compressor
Implementation Method 4
an expansion means followed by an evaporator connected to an inlet of the aforementioned compressor
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Device for cool drying a gas that consists of a closed cooling circuit (2) with a compressor (3), and which further in the direction of flow (M) of the coolant successively contains a condenser (5), an expansion means (7) followed by an evaporator (8), that constitutes the primary part of a heat exchanger (9) with a secondary part (10) through which the gas to be dried is guided, and whereby there is a bypass pipe (17) in the cooling circuit (2) that can be closed by means of a bypass valve (18) with a valve element (23) and a pressure-sensitive element (30) acting on it that is exposed to a local control pressure in the cooling circuit (2), whereby the control pressure pipe (38) is connected to the closed cooling circuit (2) upstream of the outlet of the evaporator (8).