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Celrith sintered activated carbon stick filter Ф37.5×75 is a coconut-shell carbon block water filter that reduces chlorine, odours, colour, and heavy metals such as lead and mercury, while softening water through built-in ion exchange resin. It suits point-of-use purifiers, reverse osmosis systems (as a CTO or T33 stage), direct-drinking dispensers, refrigerator water filters, and commercial coffee machines. By combining high-iodine-value coconut carbon with food-grade resin in a sintered structure, it relieves the contaminant load that causes bad taste, scale, and premature wear in downstream equipment.
Municipal water may carry residual chlorine, organic matter, off-tastes, and traces of heavy metals. In appliances, these contaminants do more than affect taste: chlorine and organics can degrade seals and membranes, while hardness minerals form scale that clogs flow paths and reduces heat-transfer efficiency. Fine particles such as rust and sediment can also pass through simple screens and deposit inside valves and pumps.
Celrith’s carbon stick is designed to address these issues at the point of use. The coconut-shell carbon has a high iodine value, giving it a large internal surface area for adsorbing chlorine, volatile organic compounds (VOCs), and colour bodies. The integrated ion exchange resin targets hardness ions and heavy metals, softening the water and reducing scaling potential. The sintered block structure provides uniform micropores that trap particulate matter without releasing carbon fines downstream.
When untreated water flows through a purifier or appliance, the cumulative load of contaminants shows up as reduced flow, taste complaints, and maintenance calls. Chlorine attacks rubber components and thin-film membranes; scale narrows pipes and coats heating elements; sediment abrades pump impellers. In coffee machines, even small amounts of chlorine and organics can distort flavour and accelerate scale buildup in boilers.
By reducing these contaminants before they reach sensitive components, the Celrith filter helps maintain flow rates and protect downstream parts. Its high adsorption capacity means it can hold more contaminant mass before saturation, extending the interval between replacements. The absence of carbon fines also prevents clogging of fine orifices and post-filters.
Celrith manufactures the sintered carbon stick using a fully flexible forming process. The carbon and resin are blended and sintered into a rigid block with precise dimensions. The Ф37.5×75 mm size is part of a standard range that also includes diameters from 30 mm to 60 mm and various lengths; custom sizes, inner/outer diameter ratios, and end-cap welding are available under OEM/ODM. This flexibility allows the filter to fit compact domestic purifiers as well as larger commercial units.
The filter operates at a rated flow of approximately 0.5–1.0 L/min, with a typical filtration accuracy of 5–10 micrometres. It removes ≥95% of residual chlorine and reduces VOCs, odours, and colour. The ion exchange resin contributes softening and heavy-metal reduction, helping prevent scale and meeting water safety expectations. Because the block is sintered, it does not release loose carbon particles, so downstream components stay clean.
Celrith also offers formulation adjustments: iodine value, CTO ratio, and filtration accuracy can be tuned to specific water conditions. This is useful where source water varies widely or where a particular contaminant challenge exists. The result is a filter that can be matched to the application rather than forcing the application to accept a one-size-fits-all cartridge.
| Item | Detail |
|---|---|
| Product name | Carbon Block Water Filter / CTO Filter for water purifiers and refrigerators |
| Core filtration material | High iodine value coconut shell carbon + food-grade ion exchange resin |
| Core performance | Softens water and inhibits scaling, adsorbs residual chlorine (bleach), removes off-colour and odour, reduces harmful heavy metals such as lead and mercury |
| Accuracy and service life | Uniform micropore structure, high initial flow, high filtration accuracy, no carbon fines; large adsorption capacity for long service life |
| Standard sizes (outer diameter × length, mm) | Ф60×130 / Ф62×240 / Ф37.5×75 / Ф38×57 / Ф40×195 / Ф51×127 / Ф32×126 / Ф32×106 |
| Main end applications | Household reverse osmosis purifiers (RO pre-filter CTO / post-filter T33), direct-drinking dispensers, side-by-side refrigerator water filters, commercial coffee machines |
| Customisation | Full OEM/ODM support. Custom moulding for length, diameter, and inner/outer diameter ratio; end-cap welding available |
| Quality certification | Production base (20,000 m²) certified to ISO 9001 and IATF 16949. Filter media meet strict water-contact safety and hygiene standards, with quality control backed by a national CNAS testing centre. |
| Rated flow | Approximately 0.5–1.0 L/min |
| Filtration accuracy | Typically 5–10 micrometres |
| Chlorine removal | ≥95% |
This carbon stick is used by manufacturers and brand owners of household water purifiers, especially reverse osmosis systems where it serves as a pre-filter (CTO) to protect the RO membrane or as a post-filter (T33) for taste polishing. It is also found in direct-drinking water dispensers, side-by-side refrigerators with built-in water filters, and commercial coffee machines where water quality affects beverage taste and machine longevity.
Because the filter can be customised in size, formulation, and end-cap design, it suits both standard cartridge platforms and proprietary designs. OEM/ODM customers use Celrith’s engineering support to develop filters that match their specific flow requirements, contaminant challenges, and installation spaces.
Celrith products comply with REACH and RoHS environmental regulations, and compliance documents are available on request. The company holds ISO 9001, ISO 14001, and ISO 45001 certifications, and in 2024 obtained IATF 16949 automotive quality management certification. These systems govern quality and environmental management across the manufacturing process.
The production base in Zhongshan, Guangdong, China, covers 50,000 m², including six cleanrooms totalling 20,000 m². The on-site laboratory is CNAS-accredited and can issue test reports for filtration efficiency, dust holding capacity, and resistance. With more than 20 years of experience in filtration research and manufacturing, Celrith has developed over 1,000 filtration solutions and exports to Europe, the United States, Japan, and South Korea.
Quality control follows IQC, IPQC, and OQC procedures, and multiple automated production lines support monthly output in the millions of pieces. This capacity, combined with a mature supply chain, helps ensure stable delivery for both standard and custom orders.
To receive a tailored quote or discuss a custom specification, please contact our team. It helps if you can provide the following details:
Send your inquiry through our contact page and we will respond promptly with technical recommendations and pricing.
It reduces residual chlorine by ≥95%, adsorbs volatile organic compounds (VOCs), off-odours and colour, and through the integrated ion exchange resin it softens water and reduces heavy metals such as lead and mercury. It also traps particulate matter down to 5–10 micrometres. This combination addresses taste, scale, and health-related impurities in one cartridge.
By removing chlorine, organics, and hardness minerals before they reach sensitive components, the filter helps prevent membrane degradation, scale buildup, and sediment clogging. This supports stable flow and reduces maintenance frequency. The sintered block does not release carbon fines, so fine orifices and post-filters stay clean.
Yes. Celrith offers full OEM/ODM customisation, including outer diameter, length, inner diameter ratio, end-cap welding, and formulation adjustments such as iodine value and CTO ratio. Standard sizes range from Ф30 to Ф60 mm in diameter. Provide your device model and space constraints, and our engineers will recommend a matching design.
For the standard Ф37.5×75 size, samples are typically free; you only cover international courier costs. Stock samples ship in about 3–5 working days. Custom specifications require a sample development period of 7–15 working days, during which we confirm a detailed specification sheet to ensure the sample meets your requirements.
The MOQ for the standard Ф37.5×75 carbon stick is usually 5,000–10,000 pieces, depending on packaging. Customised products are evaluated case by case. Standard lead time is 15–25 days, supported by the 50,000 m² production base and mature supply chain. Long-term customers can arrange rolling deliveries or VMI stock to shorten lead times.
Replacement is typically every 3–6 months, depending on water quality and daily usage. Higher contaminant levels or larger volumes will shorten the interval. Monitoring flow rate and taste is a practical guide; when flow drops noticeably or taste changes, it is time to replace.
The production base is certified to ISO 9001 and IATF 16949, and the company holds ISO 14001 and ISO 45001. Products comply with REACH and RoHS, and compliance documents are available. The on-site CNAS-accredited laboratory provides testing for filtration efficiency, dust holding capacity, and resistance.
Yes. We can provide REACH and RoHS compliance documents, and test reports from our CNAS-accredited laboratory. For specific market requirements, please let us know your target region and we will advise on available documentation. Contact our team to discuss your project.