The KFK-3 is a Soviet-era photometer that is still widely used in laboratories across Russia, the CIS, Africa, and Asia. It has been in production since the 1980s at the Zagorsk Optical-Mechanical Plant (ZOMZ), and thousands of units are still in service today. Despite its age, the KFK-3 remains reliable, repairable, and accurate enough for most routine photometric measurements.
This guide is for English-speaking engineers, lab technicians, and researchers who work with the KFK-3 but don’t have documentation in their language. We’ll cover the device’s specifications, how to read Russian markings, common issues, and where to get a proper English manual.
1. What is the KFK-3?
2. Modifications: KFK-3, KFK-3-01, -02, -03, -30MZ
3. Key technical specifications
4. How to read Russian markings
5. Common issues and troubleshooting
6. Verification (poverka) in Russia — what it means
7. Where to get the English manual
8. Frequently asked questions
9. Checklist: preparing the KFK-3 for use
1. What is the KFK-3?
The KFK-3 (Russian: КФК-3) is a single-beam photometer (photocolorimeter) designed for measuring the transmittance and optical density of transparent liquid solutions. It operates in the visible and near-infrared spectral range from 315 to 990 nm.
The device is used in environmental monitoring, drinking water analysis, food industry, metallurgy, chemical plants, and educational laboratories. It measures the concentration of dissolved substances by comparing the light intensity before and after passing through a sample.
The KFK-3 is registered in the Russian State Register of Measuring Instruments (Gosreestr SI) under number 32672-06. This means it is legally approved for use in regulated fields.
2. Modifications: KFK-3, KFK-3-01, -02, -03, -30MZ
The KFK-3 family includes several modifications. They look similar but differ in interface, automation, and features.
| Model | Key feature | Typical use |
|---|---|---|
| KFK-3 | Base version, manual cuvette change, no PC interface | Routine measurements |
| KFK-3-01 | RS-232 port for PC connection | Most common in labs |
| KFK-3-02 | RS-232 + thermal printer output, improved cuvette thermal stabilization | Medical and biochemical tests |
| KFK-3-03 | USB/RS-232, semi-automatic flow-through cuvette system | High-throughput labs |
| KFK-3-30MZ | Same as KFK-3-01; «30MZ» is a plant code (ZOMZ) | Export and domestic |
3. Key technical specifications
Below are the main specifications of the KFK-3, as listed in the Gosreestr SI and the manufacturer’s documentation.
| Parameter | Value |
|---|---|
| Spectral range (display), nm | 315 – 1000 |
| Spectral range (measurement), nm | 330 – 780 |
| Transmittance range, % | 1 – 93 |
| Optical density range (display), B | 0 – 3 |
| Optical density range (measurement), B | 0.004 – 2 |
| Wavelength setting accuracy, nm | ±3 |
| Absolute transmittance error, % | ±0.6 |
| Light source | Halogen lamp KGM12-10-2 |
| Cuvette path lengths, mm | 1, 3, 5, 10, 20, 30, 50, 100 |
| Power supply | 220 V, 50 Hz |
| Power consumption, VA | ≤ 60 |
| Dimensions, mm | 405 × 360 × 165 |
| Weight, kg | ≤ 11 |
4. How to read Russian markings
If your KFK-3 has Russian labels (which most do), here is what they mean.
| Russian | Latin / English | Meaning |
|---|---|---|
| Т (T) | T | Transmittance mode |
| А (A) | A | Optical density (absorbance) mode |
| С (S) | C | Concentration mode |
| ДЛИНА ВОЛНЫ | Wavelength | Wavelength setting knob |
| НЕТ СВЕТА | No light | Lamp failure or optic path blocked |
| ПРОГРЕВ ПРИБОРА | Warming up | Device is warming up |
| ГОТОВ К РАБОТЕ | Ready | Device ready for measurements |
| МПИ | MPI | Verification interval (usually 1 year) |
| Госреестр | Gosreestr | State Register of Measuring Instruments |
5. Common issues and troubleshooting
Most KFK-3 problems fall into three categories. Below are the typical symptoms and what to do.
1. Lamp failure (most common)
The KGM12-10-2 halogen lamp has a service life of about 250 hours. When it fails, the device loses sensitivity or won’t zero at all.
Symptoms: «No light» error, unstable readings, cannot set 100% transmittance.
What to do: Replace the lamp. After replacement, realign the light spot — this is critical for accurate measurements.
2. Power supply and electronics
The device consumes up to 60 VA. In buildings with unstable voltage, the power supply or control board may fail.
Symptoms: Random reboots, blinking indicator, device won’t turn on.
3. Optics contamination
Dust, residue from samples, and fingerprints on cuvettes can cause drifting readings.
Symptoms: Unstable results, cannot reach 100% transmittance, high noise level.
6. Verification (poverka) in Russia — what it means
In Russia, all measuring instruments used in regulated fields must pass periodic verification (Russian: poverka). This is different from calibration:
- Poverka — mandatory, state-regulated procedure. Confirms that the device meets its declared metrological characteristics.
- Calibration — voluntary procedure for devices outside state regulation.
For the KFK-3, the verification interval (MPI) is 1 year. After any repair that touches the optics or electronics, an extraordinary verification is required.
7. Where to get the English manual
The original KFK-3 manual (Russian) is available in PDF. An English translation is in progress. If you need it urgently, please contact us — we can share the relevant sections or the full document once it’s ready.
8. Frequently asked questions
Can I use the KFK-3 outside Russia?
Yes. The device is technically sound and works with 220 V / 50 Hz. In countries with 110 V or 60 Hz, a step-up transformer is needed.
How often should I verify the KFK-3?
Every 1 year if used in regulated fields. For internal use, calibration is sufficient.
What lamp does the KFK-3 use?
KGM12-10-2 halogen lamp, ~250 hours lifespan. After replacement, realignment of the light spot is mandatory.
Can I repair the KFK-3 myself?
Only basic tasks (lamp replacement, optics cleaning). For anything deeper — power supply, control board, monochromator — contact a service center.
Do you ship spare parts to other countries?
Yes, we work with labs in CIS countries and beyond. Contact us for details.
Does the KFK-3 support a computer connection?
Yes, models KFK-3-01, -02, and -03 have RS-232 or USB ports. The base model does not.
9. Checklist: preparing the KFK-3 for use
- Place the device on a stable, level surface, away from direct sunlight
- Connect to a properly grounded 220 V / 50 Hz power source
- Turn on and wait for the «Ready» signal (about 10 minutes warm-up)
- Set the required wavelength
- Place the reference cuvette in the far holder
- Place the sample cuvette in the near holder
- Calibrate: press «#» to set 100% transmittance (or 0 absorbance)
- Move the cuvette holder to the right to measure the sample
- Repeat 3 times and take the average
- Record the result and clean the cuvettes after use
📞 Need help with your KFK-3?
We work with KFK-3 photometers and other Soviet-era lab equipment since 2008. We can help with:
- Diagnostics and repair
- Lamp replacement and optical realignment
- Calibration and verification
- Spare parts for KFK-3, KFK-2, SF-46, and other models
- Shipping to CIS countries and beyond
Describe your issue and we’ll get back to you with what can be done and an estimate. Diagnostics is free if you repair with us.