Digital refractometers measure the refractive index of a gel, liquid or solid sample to in order to determine the sample’s concentration. Since more concentrated samples bend light at a larger angle, digital refractometers operate by illuminating the sample against a prism and digitally measuring the angle of refracted light with photodiode detectors. Digital refractometers are used to measure a variety of substances, from the concentration of sugar in grape juice to the purity of solvents, and are widely employed in production and quality control applications in the food, chemicals and pharmaceutical industries. Digital refractometers may be designed for manual, semi-automatic or fully automatic sample reading. Compared to an analog instrument, a digital refractometer offers quick and extensive selection between measurement units and easily exports results. The upper and lower reading limits vary significantly between digital refractometer models. Temperature-controlled digital refractometers, for ranges up to 10 to 120°C, provide better accuracy by compensating for the changes in a sample’s refractive index caused by heat or cold. Handheld digital refractometers offer convenience but may be less accurate and require larger sample sizes compared to desktop instruments. Some digital refractometer models are designed for specific applications with more limited capabilities but optimized performance.
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| Company | Rudolph Research Analytical | Rudolph Research Analytical | Rudolph Research Analytical | Rudolph Research Analytical | Rudolph Research Analytical |
| Item | J457 Automatic Refractometer | Contact Lens Refractometer J457CLR | J257 Wide Range Automatic Refractometer | J357 High Performance Automatic Refractometer | J47 and J47 WR Refractometers |
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| Catalog Number | J457-SC / J457-FC / J457-WC | Refractometer J457CLR | Inquire | Inquire | Inquire |
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| Description | All J457's come with Smart Measure™ Technology that automatically detects when the prism is improperly cleaned, insufficient sample is loaded, or if the instrument is improperly calibrated.
Exclusive Dual Temperature Control System
All J457 models come with Rudolph's exclusive Dual All J457's come with Smart Measure™ Technology that automatically detects when the prism is improperly cleaned, insufficient sample is loaded, or if the instrument is improperly calibrated.
Exclusive Dual Temperature Control System
All J457 models come with Rudolph's exclusive Dual Temperature Control System utilizing Peltier Technology. The J457 heats and cools the sample from both prism surface and sample cover. The insulating cover housing seals the Prism Well Ring to create a uniform temperature environment providing unmatched temperature control uniformity
Features - Dirty prism detection
- Incorrect calibration detection
- Insufficient sample load detection
- Cross contamination detection
- Improper water zero detection
- Trapped air bubble on prism surface detection
... Read More | Rudolph's Contact Lens Refractometers are designed for measurement of contact lenses both hard and soft as well as accurately checking saline solutions. | Rudolph Research Analytical, working together with refractometer users from the polymer, petroleum, pharmaceutical and essential oil industries, has developed the J257 Wide Range Automatic Refractometer. The J257 Refractometer features include electronic cooling and heating with an extended Rudolph Research Analytical, working together with refractometer users from the polymer, petroleum, pharmaceutical and essential oil industries, has developed the J257 Wide Range Automatic Refractometer. The J257 Refractometer features include electronic cooling and heating with an extended refractive index range.
Application: The J257 is designed as a multi purpose refractometer for a broad range of refractive index applications. The wide refractive index range of 1.26-1.70 means that this instrument can measure many materials that a refractometer with a food refractive index range of 1.33-1.53 cannot.
Operation: Operating the J257 is as simple as placing a sample on the prism, closing the cover and reading the answer — all in just a few seconds. There are no shadow lines to match and there is no eyepiece requiring any kind of operator determination or manual adjustment. When the "measure when stable" mode is selected, the J257 automatically waits until the sample has been heated or cooled to a predefined temperature before initiating a measurement.
Interface: A large 7.5cm x 10cm cold cathode fluroescent back lit graphics LCD allows the scale, sample temperature, set temperature, air temperature, time, date, and temperature correction status to be easily viewed. All functions are activated through a touchscreen panel that will not wear out or get misplaced like traditional or detachable keyboards. The touchscreen is resistant to fingernails, sharp objects, chemicals, and acids.
Dual Temperature Control System: Unlike other temperature controlled refractometers, the J257 has temperature control from both above and below the sample. The sample cover is controlled to the same temperature as the prism and, when lowered, is designed to provide a temperature controlled micro environment that provides unrivaled temperature stability, fast measurement time and minimal evaporation. Depending on options, the sample cover can also be used to initiate measurement. This means that the operator doesn't even need to touch the refractometer screen on a day to day basis, simple lower the cover and measurement starts automatically.... Read More | Designed as a research quality instrument the J357 has the highest performance of any refractometer in the Rudolph range. This instrument offers the same extra wide range as our chemical industry models combined with the high accuracy of our food industry models. It also offeres the most powerful Designed as a research quality instrument the J357 has the highest performance of any refractometer in the Rudolph range. This instrument offers the same extra wide range as our chemical industry models combined with the high accuracy of our food industry models. It also offeres the most powerful temperature control and is able tot measure at up to 120 °C
Operation: Operating the J357 is as simple as placing a sample on the artificial sapphire prism, closing the presser and reading the answer -- all in just a few seconds. There are no shadow lines to match and there is no eyepiece requiring any kind of operator determination or manual adjustment. When the "measure when stable mode" is selected, the J357 automatically waits until the sample has been heated or cooled to a predefined temperature before initiating a measurement.
Dual Electronic Temperature Control to 120C: Unlike other temperature controlled refractometers, the J357 has temperature D6control from both above and below the sample. The sample cover is controlled to the same temperature as the prism and, when lowered, is designed to provide a temperature controlled micro environment that provides unr+D18ivaled temperature stability, fast measurement time and minimal evaporation. With he Auto Measure option, the sample cover can also be used to initiate measurement.... Read More | The Rudolph J47 and J47 WR refractometer features a fully automatic measuring system designed to meet the unique needs of a food and beverage testing where the samples are mostly a mixture of sugar and water and the refractometer is viewed more as a tool than a laboratory instrument. The J47’s The Rudolph J47 and J47 WR refractometer features a fully automatic measuring system designed to meet the unique needs of a food and beverage testing where the samples are mostly a mixture of sugar and water and the refractometer is viewed more as a tool than a laboratory instrument. The J47’s single flat measurement surface, temperature correction and one button measurement capability make it perfect for heavy use applications.
Features: - Temperature Correction (ICUMSA or custom)
- High accuracy in appropriate circumstances
- High durability sapphire prism
- Lower cost of use
- 1 or 2 point user calibration
- Easy to clean measurement surface
... Read More |
| Refractive Index Range | 1.26 to 1.72 RI | 1.26 to 1.72 RI | 1.26 - 1.72 RI | 1.26 - 1.72 RI | 1.32 to 1.53 RI or 1.30 to 1.7 RI (model dependent) |
| Brix Range | 0 to 100 BRIX | 0 to 100 BRIX | 0 - 100 BRIX | 0 - 100 BRIX | 0 to 100 BRIX |
| Resolution | ±0.00001 RI (or 0.001 BRIX) | ±0.00001 RI (or 0.001 BRIX) | ±0.0001 RI (or ±0.00001 RI Optional or ±0.01 BRIX) | ±0.00001 RI (or ±0.001 BRIX) | ±0.00001 RI (or ±0.01 BRIX) or ±0.0001 RI (or ±0.1 BRIX) (model dependent) |
| Temperature Range | 10°C to 110°C | 10°C to 110°C | 10°C to 100°C (±10°C Optional) | 10°C to 100°C (±10°C Optional) | 4°C to 95°C |
| Optical Wavelength | 589.3 nm | 589.3 nm | 589.3 nm | 589.3 nm | 589.3 nm |
| Measuring Time | < 30 seconds (User configurable) | < 30 seconds (User configurable) | 20 Seconds | < 2 seconds | < 5 seconds |
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