Manifold heat pipes

Heat pipes are created in the nozzle casing, while the nozzle is heated by a band heater or just by the heat from the manifold (in the case of certain manifold nozzles). This method helps in the processing of plastics with a narrow processing temperature range (including PVC). 

Heat pipes. In an attempt to balance ont the temperatnres along the flow path, the company Dynisco HotRunners has fitted its manifolds with rectilinear tubular heaters, and also with heat pipes (see Figure 4.86). 

The heat pipes are set between the flow channel and the tnbular heaters. According to the manufacturer, this method creates isothermal conditions for the process in the manifold, and facilitates the processing of plastics with a narrow temperature window, like PVC. 

Figure 4.86 Manifold with screw-in nozzles and heat pipes...

In the classic D-M-E version, the manifold has large-diameter (24-50 mm) drilled flow channels in which cartridge heaters in a tubular body are located. The melt thus flows through an annular channel between 4 and 9 mm wide (see Chapter 1). Because of the heating pipe in the centre of the channel, the channels cannot cross over as in externally-heated manifolds, but must be connected adjacently. Torpedoes must also be connected with a butt joint to the flow channels. This creates certain restrictions as regards the mould cavity arrangement, and it is not easy to achieve a natural flow balance (see Figure 4.91). 

Pump sets, intake screens and filters, valves, manifold, crane Piping prefabrication and erection with supports, connections to heat exchangers (interfaces with other systems) Cabling and connections, earthing, cathodic protection Low suction level and vibration protection on pumpsets, pressure and flow measuring systems, cabling, etc. 

Indirect-Heat Rotary Steam-Tube Dryers Probably the most common type of indirec t-heat rotaiy diyer is the steam-tube diyer (Fig. 12-69). Steam-heated tubes running the full length of the cylinder are fastened symmetrically in one, two, or three concentric rows inside the cylinder and rotate with it. Tubes may be simple pipe with condensate draining by gravity into the discharge manifold or bayonet-type. Bayonet-type tubes are also employed when units are used... 

Flash steam. This will result from the blowdown heat recovery referred to in Section 7.13. Flash steam is introduced into the tank through a dip pipe terminating in a distribution manifold near the bottom of the tank. 

The blowdown from the boiler(s) will be run to a flash-steam vessel mounted adjacent to the feed tank. Flash steam will be introduced into the feed tank through a dip pipe terminating in a distribution manifold. The drain from the flash vessel may then be taken to a residual blowdown heat exchanger. Any remaining heat is then transferred to the make-up water to the tank before the blowdown runs to drain. 

Heat loss in the exhaust pipe from the exhaust manifold to the converter can also be analyzed by Eq. (30). The flow is turbulent, and Nu depends on (Re)2/S. Assuming a tail pipe that is 3 ft long, and a Reynolds number of 30,000, the results of the computation are also shown in Table VII. Due to the low surface area, only 20% of the temperature above the wall temperature would be lost through the walls, and 80% would arrive at the converter inlet. As the gas velocity increases, heat loss through the... 

The micro-channels utilized in engineering systems are frequently connected with inlet and outlet manifolds. In this case the thermal boundary condition at the inlet and outlet of the tube is not adiabatic. Heat transfer in a micro-tube under these conditions was studied by Hetsroni et al. (2004). They measured heat transfer to water flowing in a pipe of inner diameter 1.07 mm, outer diameter 1.5 mm, and 0.600 m in length, as shown in Fig. 4.2b. The pipe was divided into two sections. The development section of Lj = 0.245 m was used to obtain fully developed flow and thermal fields. The test section proper, of heating length Lh = 0.335 m, was used for collecting the experimental data. 

The car, which he runs on a daily basis, is a restored, eight-cylinder 1978 Chevy Camaro with stock 350 (5.7 litre) engine, no computer controls, automatic transmission, stock 4-barrel carburettor and stock fuel pump. The fuel tank has been replaced with a metal water tank with the filler cap vented to release heat and pressure. The exhaust was replaced with a new 2 inch pipe which is ducted into the water tank. The water tank has baffles inside it which also muffles the exhaust noise. The stock exhaust manifolds were used, but they will rust on the inside - custom stainless steel pipes would be best but these were not used due to their cost. 

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