Permissible Operating Conditions
Typical External Heat Transfer Co-efficient.
The glass process plant and pipeline components detailed in this catalogue have either standard flat buttress ends (Type A + B from DN 25 to DN 450)
The following table provides dimensional information on standard flat buttress ends form for the range of glass components detailed in this catalogue.
A + B
Maximum Working Pressures
Depending on shape and working conditions, glass components can be used, under certain circumstances, at higher internal pressures.
Although bar is a measure of absolute pressure, throughout these pages the figures given for maximum recommended working pressure represent pressures above atmospheric; i.e., "gauge" pressure.
Because of the potential energy of gases under pressure, we recommend you specify and provide safeguards for equipment and personnel in the unlikely event of a systems failure. For the same reason, pressurized as should not be used to test a system.
All sizes are safe for use under full vacuum.
Borosilicate glass retains its mechanical strength and will deform only at temperatures which approach its strain point. The practical upper limit for operating temperatures Is much lower and is controlled by the temperature differentials in the glass, which depend on the relative temperatures of the contents of the equipment and the external surroundings.
provided borosilicate glass is not subjected to rapid change in temperature, creating undue thermal shock, it can be operated safely at temperatures up to 4500F (2320C). The normal limiting factor is actually the gasket material. The degree of thermal shock (usually defined as sudden chilling) which it can withstand depends on many factors, for example: stresses due to operating conditions; stresses imposed in supporting the equipment; the wall thickness of the glass, etc. It is therefore undesirable to give an overall figure but, as a general guide, sudden temperature changes of up to about 2160F (1200C) can be accommodated
At sub-zero temperatures, the tensile strength of borosilicate glass tends to increase and equipment can be used with safety at cryogenic temperatures It is always advisable to discuss any difficult applications with our engineers.
Jacketed components are designed to complement the standard range of glass process plant and pipeline equipment's detailed in this catalogue by extending the range of applications for which glass can be used. Jacketed components, as their name implies, are standard glass components with a glass jacket around them. The jacket is sealed onto the glass component with silicone rubber.
Jacketed components are not only used to avoid heat loss for the purpose of saving energy, but also where the product characteristics have to be maintained to prevent crystallizing or unwanted reactions from occurring. A further area of application is thermal insulation where the ability to still monitor the process visually is a major advantage.
Jacketed versions of all the major glass components detailed in this catalogue are available. The range therefore includes pipeline components, valves and vessels as well as a wide variety of column components and heat exchangers.
Permissible Operating Conditions
For the inner part of jacketed components, the permissible operating pressure are identical to those for their non-jacketed counterparts. These pressures are detailed in the previous pages of this section.
However, deviations will arise in the permissible operating temperature for the inner component and the permissible operating conditions in the jacket itself. These are due to permanently flexible silicone seal, which absorbs the different expansion levels of the inner component and jacket.
Permissible Operating Temperature
The permissible operating temperature for the inner component is -40°C to +_150°C. For the jacket it is -40°C to +130°C.
In special circumstances, the operating temperature can be increased to +170°C for the inner component and +150°C in the jacket.
Permissible Operating Pressure
The permissible operating pressure in the jacket is –0.2bar.g to + 0.1bar.g, unless lower values are derived from Figure 3 to 8 on the previous pages.
If there is a vacuum in the jacket, care must be taken to ensure that the pressure difference between the inner component and the jacket does not exceed the permissible operating pressure for given Figure 3 to 8 on the previous pages.
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