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EXPANSION VALVES FOR REFRIGERATING SYSTEMS

EXPANSION VALVES FOR REFRIGERATING SYSTEMS
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EXPANSION VALVES FOR REFRIGERATING SYSTEMS

Product catalog summary
Overview: The document provides comprehensive information on Castel's expansion valves used in refrigeration and air conditioning systems. It emphasizes the company's commitment to quality, certified by UNI EN ISO 9001:2008, and compliance with EEC Directives and both European and American quality standards.
Product Specifications: The document details the specifications of thermostatic expansion valves, highlighting their application in systems such as refrigeration, air conditioning, heat pumps, and liquid chillers. It describes the construction of the valves, which include a body and an interchangeable orifice assembly, made from materials like stainless steel and forged brass.
Operation and Functionality: Thermostatic expansion valves regulate refrigerant flow based on superheat levels to ensure efficient evaporator use. The document explains the operation mechanism, focusing on the thermostatic element and orifice assembly's role in controlling refrigerant flow.
Technical Standards and Testing: All products undergo tightness and pressure containment tests, adhering to standards like EN 12284:2003 and Directive 97/23/EC. The valves are tested for external leakage and pressure strength to ensure reliability and safety.
Warranty and Guarantee: Castel offers a 12-month warranty covering defects, with specific conditions for returns and replacements. The warranty excludes damages from incorrect installation or misuse.
Selection and Installation: A step-by-step guide is provided for selecting the appropriate expansion valve, considering factors such as refrigerant type, evaporator capacity, and pressure conditions. Instructions for ordering components based on connection types (SAE Flare or ODS) are included.
Tables and Data: The document includes tables detailing the general characteristics of body assemblies, orifice assemblies, and rated capacities, providing essential data for selecting and configuring the valves.
Specifications: Detailed specifications for various refrigerants, including R22, R407C, R134a, R404A, and R507, are provided. It includes rated capacities for different temperature ranges and conditions, such as evaporating and condensing temperatures, and refrigerant liquid temperatures ahead of the valve.
Procedures: A sizing example is provided for selecting the appropriate valve based on specific conditions like evaporator capacity, evaporating temperature, condensing temperature, and pressure drop. The procedure involves calculating the pressure drop across the valve, determining the required valve capacity using a subcooling correction factor, and selecting the appropriate orifice size from capacity tables.
Standards and Norms: The document references standards for materials used in valve construction, such as hot forged brass, copper tube, and various types of stainless steel. It also mentions compliance with European directives for refrigerant fluids.
Recommendations: Recommendations include using an electronic regulator for more accurate refrigerant metering and efficiency, and ensuring the valve is sized correctly for the system's hardest conditions. The document also advises on the use of specific coil types and connectors for optimal performance.
Construction and Materials: The valves are constructed with materials like hot forged brass, copper, and stainless steel, with interchangeable orifices for different capacities. The document specifies the materials used for various valve components, ensuring durability and compliance with industry standards.
Operations: The solenoid expansion valve operates using Pulse Width Modulation (PWM) to regulate refrigerant flow, enhancing efficiency and response to load variations. The document outlines the operational mechanism and the importance of correct valve sizing.
Pressure Drop Calculation: The pressure drop across the valve is calculated using the formula Δptot = Pc - Pe + Δp, where Pc is the condensing pressure, Pe is the evaporating pressure, and Δp is the sum of pressure drops in the liquid line, distributor, and evaporator.
Subcooling Correction: Use the evaporating capacity Qe to select the required valve size at a given evaporating temperature. Correct the evaporator capacity for subcooling using the formula ΔTsub = Tc - Tl. Find the corrector factor Fsub from the subcooling corrector factor table and calculate the required valve capacity as Qsub = Qe * Fsub.
Application Correction: Oversize the valve to ensure its closing period is between 25% and 50% of the total period T of the regulator. The correcting factor Fev is dependent on the evaporation temperature, with Fev = 1.25 for Tev >= -15°C and Fev = 1.50 for Tev <= -15°C. Calculate the corrected valve capacity as Qev = Qsub * Fev.
Orifice Size Determination: Use the pressure drop across the valve, the evaporating temperature, and the calculated evaporator capacity Qe to select the corresponding orifice size from the capacity table for the chosen refrigerant.
Liquid Line Sizing: Since the valve is an ON/OFF type, size the diameter of the pipes in the liquid line according to the maximum flow rate across the orifice to avoid decrement of valve capacity due to pressure drop.
Sizing Example: For refrigerant R404A with an evaporator capacity of 2.8 kW, evaporating temperature of -5°C, condensing temperature of +35°C, liquid refrigerant temperature of +20°C, and a pressure drop of 2 bar, the steps are as follows:
  • Calculate pressure drop: Δptot = 9.76 bar.
  • Determine valve capacity: ΔTsub = 15°C, Fsub = 0.83, Qsub = 2.324 kW.
  • Application correction: Fev = 1.25, Qev = 2.91 kW.
  • Select orifice size: Use capacity table for R404A with a pressure drop of 9.76 bar and evaporating temperature of -5°C to select orifice 04.
Tables: The document includes tables with general characteristics of PWM expansion valves, coils, orifice sizes, and rated capacities for various refrigerants (R22, R134a, R404A/R507, R407C, R410A) at different pressure drops. Correction factors for subcooling are also provided.
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Catalog excerpts

EXPANSION VALVES FOR REFRIGERATING SYSTEMS-1

EXPANSION VALVES FOR REFRIGERATING SYSTEMS FROM QUALITY OUR NATURAL DEVELOPMENT Achieved the goal of fty years working in the industry of Refrigeration and Air Conditioning, Castel Quality Range of Products is well known and highly appreciated all over the world. Quality is the main issue of our Company and it has a special priority, in every step, all along the production cycle. UNI EN ISO 9001:2008, issued by ICIM, certies the Quality System of the Factory. Moreover Castel Products count a number of certications in conformity with EEC Directives and with European and American Quality Approval. We produce on high tech machinery and updated automatic production lines, operating in conformity with the safety and environment standards currently enforced. Castel oers to the Refrigeration and Air Conditioning Market and to the Manufacturers fully tested products suitable with HCFC and HFC Refrigerants currently used in the Refrigeration & Air Conditioning Industry. Expansion valves 1

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EXPANSION VALVES FOR REFRIGERATING SYSTEMS-3

INDEX THERMOSTATIC EXPANSION VALVES SERIES 22 PWM SOLENOID EXPANSION VALVES EXTERNAL LEAKAGE All the products illustrated in this Handbook are submitted, one by one, to tightness tests besides to functional tests. Allowable external leakage, measurable during the test, agrees to the denition given in Par. 9.4 of EN 12284 : 2003 Standard: “During the test, no bubbles shall form over a period of at least one minute when the specimen is immersed in water with low surface tension, …”. PRESSURE CONTAINMENT All the products illustrated in this Handbook, if submitted to hydrostatic test, guarantee a...

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EXPANSION VALVES FOR REFRIGERATING SYSTEMS-5

THERMOSTATIC EXPANSION VALVES SERIES 22 WITH INTERCHANGEABLE ORIFICE ASSEMBLY APPLICATION Castel thermostatic expansion valves series 22 regulate the ow of refrigerant liquid into evaporators; the liquid injection is controlled by the refrigerant superheat. e new Castel “22” series are designed to work with interchangeable orice assembly, to provide exibility in selection of capacities, and can be used in a wide range of applications as listed below: - Refrigeration systems (display cases in supermarkets, freezers, ice cream and ice maker machines, transport refrigeration etc). - Air conditioning...

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EXPANSION VALVES FOR REFRIGERATING SYSTEMS-7

materials: - stainless steel for bulb, capillary tubing, diaphragm casing, diaphragm and rod - hot forged brass EN 12420 – CW 617N for body - brass EN 12164 – CW 614N for superheat setting spindle and spring holder - steel DIN 17223-1 for spring - copper tube EN 12735-1 – Cu DHP for solder connection Orice assembly: interchangeable orice assembly provides a wide range of capacity from 0,5 up to 15,5 kW (nominal capacity with R22). e external cartridge contains the following elements: housing, plug (metering device), seat, spring and strainer. e rigid design of orice assembly and its internal...

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EXPANSION VALVES FOR REFRIGERATING SYSTEMS-8

40 43 35 66 42 Ø 39 42 29 40 Q sub Qe Fsub Step 3 Determine required orice size. Use the pressure drop across the valve, the evaporating temperature and the calculated evaporator capacity to select the corresponding orice size from the capacity table corresponding to the chosen refrigerant. Step 4 Select a thermostatic charge. Chose the type of charge, liquid without MOP or gas with MOP, and the temperature range, normal temperature or low temperature. Step 5 Determine if external equalizer is required. External equalizer is always required if a distributor is used or if there is an appreciable...

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EXPANSION VALVES FOR REFRIGERATING SYSTEMS-9

- Body assembly (see tabs 1a/1b) - Orice assembly, completed with strainer (see tab 2) If ODS connections you have to order the following three parts: - Body assembly (see tabs 1a/1b) - Orice assembly, completed with strainer (see tab 2) - Solder adapter (see tab. 3) SIZING EXAMPLE - Type of refrigerant R134a - Evaporator capacity, Qe 6 kW - Evaporating temperature/pressure, Te - 10 °C - Lowest possible condensing temperature/pressure, Tc +30 °C - Liquid refrigerant temperature, Tl + 20 °C - Pressure drop in the liquid line, distributor and evaporator, Δp 1,5 bar Table 2: Orice Assemblies - Rated...

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EXPANSION VALVES FOR REFRIGERATING SYSTEMS-14

PWM SOLENOID EXPANSION VALVE WITH INTERCHANGEABLE ORIFICE OPERATIONS CONSTRUCTION Solenoid expansion valve Castel type 2028 regulates the refrigerant ow into the evaporator by modulating the opening time phase of the plug and so permitting a wide range of power. is valve must be used with a coil type HM4 (see table 2), controlled by an electronic regulator device (not supplied by Castel). is valve is most frequently used in refrigeration systems, in particular refrigerated cabinets in the supermarket, which use the following refrigerant uids: R22, R134a, R404A, R407C ; R410A, R507 proper to the...

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EXPANSION VALVES FOR REFRIGERATING SYSTEMS-15

- Evaporating temperature/pressure, Te/pe - Lowest possible condensing temperature/pressure, Tc/pc - Liquid refrigerant temperature, T, - Pressure drop in the liquid line, distributor and evaporator, Ap The following procedure helps to select the correct valve for the Determine the pressure drop across the valve. The pressure drop is - Ap = sum of pressure drops in the liquid line, distributor and Subcooling correction. Use the evaporating capacity Qe to select the required valve size at a given evaporating temperature. If necessary, correct the evaporator capacity for subcooling. Subcooling...

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*Prices are pre-tax. They exclude delivery charges and customs duties and do not include additional charges for installation or activation options. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates.