Hygienic Fittings
Total Page:16
File Type:pdf, Size:1020Kb
INDUSTRIAL FITTINGS - couplings Stainless steel hygienic couplings Stainless steel hygienic couplings are intended for food, pharmaceutical, cosmetics and chemical industries as well as for biotechnology. At first the couplings were primarily used in dairy and brewing industry to connect pipe installations using an internal expansion method (a pipe is pressed from the inside out into a fitting). Nowadays they are welded using methods that ensure the highest quality of the weld adequate to the hygienic requirements. The hygienic couplings come in different standards that differ in terms of the type of connection and sealing that further determine different levels of hygiene of the couplings required by various applications. The hygienic design of a coupling is defined by accessible and easy cleaning and sterilization without dismantling (CIP, SIP) and use of adequate materials. The requirements for hygienic couplings are set in several regulations and standards e.g. 3-A (3-A Sanitary Standards Incorporated), EHEDG (European Hygienic Engineering & Design Group), ASME BPE-2009 (Bioprocessing Equipment). In general, the standards require to avoid all kinds of crevices or dead spaces that may cause particles accumulation and growth of microorganisms. Internal surfaces must be smooth and nonporous. The surface roughness must not exceed Ra = 0.8 µm and Ra = 0.4 µm when the requirements for the internal surface roughness are higher. Some surfaces may need electro-polishing. Welds are subject to separate requirements. The internal folds of the surface should be smoothened out by an angle that facilitates cleaning. Seals should be the closest possible to the transferred medium avoiding crevices and the risk of product getting under the seal. Coupling material Depending on the medium and level of requirements, hygienic couplings are made of AISI 304 (304L) stainless steel or (e.g. for low pH media and for higher requirements) of AISI 316 (316L) steel or other materials. Seals should be compliant with appropriate standards (e.g. FDA 21 CFR177.2600 and USP Class VI for elastomers, FDA 21 CFR 177.1550 for PTFE). DIN11851 couplings NH-DZS-050 fitting with Rd 78x1/6” male thread hygienic weld hygienic weld NH-DUS-050 seal NH-DWS-050 fitting 53x1.5 pipe (DIN 11850) 53x1.5 pipe (DIN 11850) NH-DN-050 nut with Rd 78x1/6” female thread Threaded couplings according to DIN11851 with a rounded thread (marked Rd) are widely used in food and chemical industry. A seal with a D-shaped cross section is a standard. In order to ensure higher level of hygiene a seal with a lip is used which fills the crevice between connected halves. Maximum working pressure (for a coupling according to DIN 11851 itself) is 40 bar (DN 10 ÷ DN 40), 25 bar (DN 50 ÷ DN 100) and 16 bar (DN 125 ÷ DN 150). 555 INDUSTRIAL FITTINGS - couplings Stainless steel hygienic couplings SMS couplings NH-SZS-050 fitting with Rd 70x1/6” male thread hygienic weld hygienic weld NH-SUE-050 seal NH-SWS-050 fitting 51x1.2 pipe (ISO 2037) 51x1.2 pipe (ISO 2037) NH-SN-050 nut with Rd 70x1/6” female thread Threaded SMS couplings according to Swedish standard with a rounded thread (marked Rd) are used in food industry. A seal with a rectangular cross section is a standard. The coupling facilitates dismantling of segments of installation. Maximum working pressure (for a coupling itself) is 15 bar. IDF couplings NH-IZS-050 fitting with male trapezoidal thread hygienic weld hygienic weld NH-IUN-050 seal NH-IWS-050 fitting 50.8x1.6 pipe (BS 4825-1) 50.8x1.6 pipe (BS 4825-1) NH-IN-050 nut with female trapezoid al thread Threaded IDF (International Dairy Federation, BS 4825-4 and ISO 2853 standards) couplings with a trapezoidal thread are used in food industry. A seal with a T-shaped cross section as a standard gives a crevice free design and so a high level of hygiene. Maximum working pressure (for a coupling according to BS 4825-4 itself) is 16 bar. RJT couplings NH-RZS-050 fitting with male Whitworth thread(BS-84) hygienic weld hygienic weld NH-IUN-050 seal NH-RWS-050 fitting 50.8x1.6 pipe (BS 4825-1) 50.8x1.6 pipe (BS 4825-1) NH-RN-050 nut with female Whitworth thread (BS-84) Threaded RJT couplings (Ring Joint Type, BS 4825-5 standard) with Whitworth thread are extensively used in British food industry in particular. Sealed by a thick O-ring. Very easy to dismantle. Due to a large crevice, the couplings are not suitable for cleaning without dismantling (CIP). Maximum working pressure (for a coupling according to BS 4825-5 itself) is 10 bar. 556 INDUSTRIAL FITTINGS - couplings Stainless steel hygienic couplings TRICLOVER (Tri-Clamp) couplings NH-TKS-064-050 NH-TKS-064-050 fitting fitting hygienic weld hygienic weld 53x1.5 pipe 53x1.5 pipe (DIN 11866-A) NH-TUS-064-050 NH-TO-064 clamp (DIN 11866-A) seal TRICLOVER couplings consist of two flanges („plates”) with grooves to accommodate a seal, secured by a clamp. The seal fills up the crevice between two flanges so that it ensures high hygiene of the coupling. Used in pharmaceutical, food, cosmetic and chemical industries, in biotechnology, for fluids and high viscosity media. TRICLOVER couplings are manufactured in compliance with such standards as: ISO 2852, DIN 32676, BS 4825-3 and other, which generally define the same basic dimensions of connection (see table). It is typical of TRICLOVER couplings that the diameter of the flange (A) and the internal diameter (d) correspond to the internal diameter of the pipes in the installation. The working pressure of the coupling itself depends on the size of the coupling and type of the clamp applied (at least 16 bar up to 2”, 10 bar - above 2”). ISO 1127 ASME BPE standard ISO 2852 DIN32676 - A BS 4825-3 DIN 32676 - B DIN32676 - C size DIN 11866 - A ISO 1127 ASME BPE pipe standard ISO 2037 BS 4825-1 [inch] DIN 11850 DIN 11866 - B DIN 11866 - C A B c e D d D d D d D d D d 6** 4** 6.35 4.57 1/4 8 6 10 8 10.2 7 9.53 7.75 3/8 25 20.2 3.6 0.8 12 10 13.5 10.3 12.7 9.4 12.7 9.5 1/2 (25.4*) (20.3*) (3.7*) (0*) 14** 12** 16** 14** 18** 16** 17.2 14 19.05 15.75 19.05 15.85 3/4 2.85 12 10 12.7 10.7 13 10 34 27.5 17.2 15.2 19 16 21.3 19.3 23 20 2.85 21.3 18.1 0 25 22.6 29 26 26.9 23.7 25.4 22.1 25.4 22.2 1 50.5 43.5 33.7 31.3 35 32 33.7 29.7 38 35.6 41 38 38.1 34.8 38.1 34.9 1.1/2 2.85 40 37.6 42.4 38.4 64 56.5 51 48.6 53 50 48.3 44.3 50.8 47.5 50.8 47.6 2 77.5 70.5 2.85 63.5 60.3 60.3 56.3 63.5 60.2 63.5 60.3 2.1/2 Note: * - according to BS 4825-3; ** - utilized, but not listed in a standard. 557 INDUSTRIAL FITTINGS - couplings Stainless steel hygienic couplings TRICLOVER couplings - table follow up ISO 1127, ASME BPE, standard ISO 2852 DIN32676 - A BS 4825-3 DIN 32676 - B DIN32676 - C size DIN 11866 - A, ISO 1127, ASME BPE, pipe standard ISO 2037 BS 4825-1 [inch] DIN 11850 DIN 11866 - B DIN 11866 - C A B c e D d D d D d D d D d 70 66.8 70 66 91 83.5 2.85 76.1 72.9 76.1 72.1 76.2 72.9 76.2 73 3 106 97 2.85 88.9 84.9 85 81 88.9 84.3 119 110 2.85 101.6 97.6 104 100 101.6 97.38 101.6 97.6 4 130 122 2.85 0 114.3 110.3 114.3 109.7 114.3 110.3 155 146 5.6 139.7 135.7 129 125 139.7 134.5 139.7 135.7 167 156.5 5.6 152.4 146.86 6 183 174 5.6 168.3 163.1 154 150 168.3 163.1 168.3 163.1 233.5 225 5.6 219.1 213.9 204 200 219.1 213.9 219.1 213.9 Hygiene of TRICLOVER couplings In order to ensure hygiene of a TRICLOVER coupling, both halves must have the same internal diameter. Otherwise there is a shoulder in the flange bore which creates a dead space where particles can accumulate. As cleaning of such spot requires dismantling, the connection is no longer hygienic. Therefore TRICLOVER couplings must be selected with regard to a flange diameter (A) and to a pipeline internal diameter (d). It applies to fittings that are welded in the installation and flexible hose assemblies as well. The internal diameter of a seal must be also property selected (nominally by 0.2 mm bigger than the pipeline internal diameter d). in correct correct Aseptic couplings The couplings according to DIN standard were developed to make aseptic DIN11853 and DIN 11864 couplings (compatible, of different length), available in 3 standard options: DIN 11853-1 / DIN 11864-1 - screwed Rd thread couplings DIN 11853-2 / DIN 11864-2 - flange couplings bolted together DIN 11853-3 / DIN 11864-3 - flange couplings clamped together (as TRICLOVER) All couplings are sealed with an O-ring in a special groove.