• Korean Journal of Microbiology
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• v.49 no.4
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• pp.313-320
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• 2013

Biofilm formed on stainless and copper in water treatment plant was investigated for sixteen weeks. Biofilm reactor was specially designed for this study. It was similar to that of a real distribution pipe. Raw water, coagulated, settled, filtered and treated water were used in this study. The average number of heterotrophic bacteria counts was $1.6{\times}10^4CFU/ml$, $5.8{\times}10^3CFU/ml$, $1.8{\times}10^3CFU/ml$, $1.3{\times}10^2CFU/ml$, 1 CFU/ml, respectively. Density of biofilm bacteria formed on stainless and copper pipes in raw, coagulated and settled water increased above $2.9{\times}10^3CFU/cm^2$ within second weeks while more biofilm bacteria counts were found on the stainless pipe than on the copper pipe. In case of filtered water (free residue chlorine 0.44 mg/L), there was no significant difference in the number of biofilm bacteria on both pipes and biofilm bacteria below $18CFU/cm^2$ were detected on both pipe materials after fifth weeks. Biofilm bacteria were not detected on both pipe materials in treated water (free residue chlorine 0.88 mg/L). According to the results of DGGE analysis, Sphingomonadacae was a dominant species of biofilm bacteria formed on the stainless pipe while the copper pipe had Bradyrhizobiaceae and Sphingomonadaceae as dominant bands. In case of filtered water, a few bands (similar to Propionibacterium sp., Sphingomonas sp., Escherichia sp., and etc.) that have 16S rRNA sequences were detected in biofilm bacteria formed on both pipes after fifth weeks. Stainless pipe had higher species richness and diversity than the copper pipe.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.116-119
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• 2003

본 연구에서는 LCD 공정에 사용되는 ball spacer를 전해 연마(Electro-Polishing, EP) 처리된 스테인리스(stainless)관 내부에서 마찰대전으로 하전시켜 하전량을 측정하는 하전 메커니즘과 하전 특성을 관찰하였다. Ball spacer의 농도를 일정하게 하고, 유입하는 공기의 유량을 201pm, 301pm으로 변화시키면서 실험하였다. 유입되는 공기의 유량은 일정하게 하여 ball spacer의 농도를 분진공급장치(dust feeder)를 통해 변화시키면서 하전수를 측정하였다. 이 때 측정결과는 EP 처리된 스테인리스관에 유입되는 공기의 유량이 증가했을 때, 하전이 더 많이 되는 것을 보여주었다. 또한 일정한 공기의 유량에서 주입되는 ball spacer의 농도가 증가했을 때 입자당 하전수가 증가하였다.

• 월간 기계설비
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• s.302
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• pp.78-81
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• 2015

다이아몬드표 나사식 관이음쇠로 유명한 (주)신한메탈(대표 전진화)이 최근 SH-조인트로 상표등록 하고 스테인리스 강관 조인트 시장에 본격 진출했다. 최근들어 내식성, 내마모성이 뛰어난 스테인리스강 수요가 크게 늘면서 이중링 조인트 사용이 활발해지자 스테인리스 배관 시장변화에 능동적으로 대처하기 위해서다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.200-206
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• 2010

건축환경의 변화에 따라 최근 스테인리스배관을 소방배관에 사용하고자 하나 국가화재안전기준에 관련근거가 없어 사용이 어려운 것이 현실이다. 따라서 본 논문에서는 이 기준에서 사용할 수 있는 배관가운데 동관(KS D 5301)과 일반배관용 스테인리스 배관(KS D 3595)의 성능비교를 통하여 사용가능성을 확인하였다. 비교한 성능은 강도, 내식성 및 내열성이며 유한요소해석과 관련 시험을 통해 성능을 비교한 결과 동등이상임을 확인할 수 있었다.

• Fire Science and Engineering
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• v.24 no.5
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• pp.94-101
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• 2010

The pipes using in water-based fire protection systems are used steel pipes for ordinary piping, carbon steel pipes for pressure service, copper and copper alloy seamless pipes and tubes, etc. By last buildings of high-rising, complexity, in fire protection systems, the corrosion resistance, easy construction, lightweight and cost-effective use of the pipes is being considered. Among the pipes, the possibility of used for fire protection system being used in the existing copper pipe of material properties, strength, corrosion resistance, heat resistance through and compare the performance was evaluated. As a result of that assessment light gauge stainless steel pipes for ordinary piping (KS D 3595) at a water pressure of less than 1.2 MPa can be used in sufficient physical properties, strength, corrosion resistance, heat resistance and have been observed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1203-1210
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• 2006

The filmwise condensation heat transfer coefficients of R-134a on the horizontal copper and stainless steel tubes were measured and analyzed. The outside diameter of the tubes was 15.88 mm, and the tube thickness ranged from 0.89 to 1.65 mm. The polished stainless steel tube had an RMS surface roughness($R_q$) of 0.37 $\mu$m, and commercial stainless steel tubes had an surface roughness($R_q$) of 1.855 $\mu$m. The tests were conducted at the saturation temperatures of 20 and $30^{\circ}C$, and the liquid wall subcoolings from 0.4 to $2.1^{\circ}C$. The measured condensation heat transfer coefficients were significantly lower than the predicted data by the Nusselt analysis. This trend in the stainless steel tube was explained by the effects of thermal resistance of tube material and surface roughness. Based on the experimental data with respect to wall thickness and surface roughness, it was suggested that the existing correlation on external condensation should be modified by considering material and surface roughness factors. The revised correlation was developed by introducing the effects of wall thickness and surface roughness into the Nusselt equation. The average deviation of the revised correlation was 13.0 %.

• Fire Science and Engineering
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• v.31 no.4
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• pp.65-70
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• 2017

The seismic performance of press fittings is studied, which is one of the weldless joints of stainless steel pipe used in the water piping of recent fire protection system. The piping of this study was constructed based on the piping connection reference of NFPA 13. The permissible displacement of the piping was set as the allowed amount which is given in the Building Structure Standard, and the measurements were repeated 10 times. The Von-mises stress of the piping was 2.48 and 1.25 times of the allowed amount of stress, which was less than the standard, noted three times on the NPPs Allowable Stress for Level D service loading. Therefore, the press fittings shows enough seismic performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4658-4664
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• 2013

This paper presents the effects of the tube materials on the heat transfer performance of double-tube heat exchangers for the development of heat exchangers using deep sea water. Heat exchangers made of titanium, aluminum. stainless steel, iron, copper, and aluminum with carbon black 0.015mm and 0.15mm coating were tested. Also, the heat transfer rate of each heat exchanger was calculated by using EES program. The calculated values were compared with the experimental ones, and the deviations were less than 10%. From the above experiment and analysis, aluminum with carbon black 15 coating can be considered the most promising candidate for the replacement of titanium heat exchanger.

• 월간 기계설비
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• s.288
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• pp.75-80
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• 2014

나사식 가단주철제 관이음쇠는 신한메탈, 영화테크(전신 영화금속) 외 국산 8개사, 중국산 9개사 등 모두 17개사가 공급에 참여하고 있다. 그러나 심한 가격경쟁으로 짝퉁과 중국산 제품이 판치는 시장에서 100% 국내 가공으로 최고의 품질을 자랑하며 고객과 신뢰를 쌓아가기란 여간 어렵지 않다. 나사식 가단주철제 관이음쇠 분야의 명품을 꼽으라면 설비건설업계는 대부분 다이아몬드가 표시된 제품을 집는다. 다이아몬드 표시로 더 알려진 관이음쇠 생산업체인 (주)신한메탈(대표 전진화)은 작년에 영화금속의 나사식 관이음쇠 부문을 인수한 후 경쟁력을 더욱 강화한데 이어 최근에는 엘보, 티 등 스테인리스 조인트 가공시장에 본격 진출하기 위해 생산시설 도입에 박차를 가하고 있다.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.258-266
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• 2011

Scale induced by hardness materials in water must be controled because of it can be result in remarkable damages of pipeline as well as water quality deterioration. Especially hot water system is one of scale management required facility as scale formation can be accelerated by temperature. The scale control performance of frequency driver (FD) was tested instead of existing methods such as chemical, physical and electromagnetic methods which needs chemicals and electric power. Three kinds of pipe coupons were submerged in test water with 500 mg/L of hardness for 33 days and XRD and SEM were analysed for comparing scale formation characteristics of these coupons. Calcite ($CaCO_3$) which came from hardness of water was formed on only cast iron pipe coupon and this coupon showed higher corrosion rate than copper and stainless steel pipe coupon. Hot water circulating system connected cast iron pipe with and without FD was operated with 300 mg/L of hardness water at $50^{\circ}C$ for monitoring of scale formation and water quality with and without FD. XRD showed that FD leaded to magnetite ($Fe_3O_4$) scale which is good scale for preventing corrosion than calcite and SEM image also indicated the scale control effect of FD. Scales of 16% on pipe joint, 14% on pipe length, and 42% on heat exchanger decreased with FD comparing scales of those parts without FD. From the results of water quality, FD reduced crystallization of hardness material without chemical reaction in water and it can indicate that FD is safe and proenvironmental technology for scale reduction.