Injection units

Injection unit consists of barrel, screw, and nozzle. The flow starts from machine barrel through the nozzle of the injection 

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Liquid Injection. Liquid injection units are the most common type of incinerator today for the destmction of Hquid hazardous wastes such as solvents. Atomizers break the Hquid into fine droplets (100—150 microns) which allows the residence time to be extremely short (0.5—2.5 s). The viscosity of the waste is very important the waste must be both pumpable and capable of being atomized into fine droplets. Both gases and Hquids can be incinerated in Hquid injection units. Gases include organic streams from process vents and those from other thermal processes in the latter case, the Hquid injection incinerator operates as an afterburner. Aqueous wastes containing less than 75% water can be incinerated in Hquid injection units. 

F11 Rotary Kiln with Liquid Injection Unit R24 Metals Recovery - Reverse Osmosis... 

The contribution of the equipment between injection unit and detector cell should be negligable in relation to the column for a sufficient column characterization short connections with narrow capillaries and zero dead volume unions are the precondition for reliable plate numbers. Every end fitting of a column causes additional band broadening. In the past a column type was offered that could be directly combined without any capillary links unfortunately, it has disappeared from the market. 

Accuracy and repeatability of temperature/time/velocity/pressure controls of injection unit, accuracy and repeatability of clamping force, flatness and parallelism of platens, even distribution of clamping on all tie rods, repeatability of controlling pressure and temperature of oil, oil temperature variation minimized, no oil contamination (by the time you see oil contamination damage to the hydraulic system could have already occurred), machine properly leveled. 

The earliest injection method in hplc used a technique borrowed from gc in which a microlitre syringe was employed to inject the sample through a self-sealing rubber septum held in an injection unit at the top of the column. In another method, (stopped flow), the flow of mobile phase through the column was halted and when... 

The application of instrumentation to the automatic control of a sequence of operations, e.g., injection moulding processes. Once the mould has been loaded with inserts (assuming a rubber to metal bonded part) into the press, the operation of a push-button starts the controller which closes the press, injects the rubber, controls the cure cycle, recharges the injection unit, opens the press, operates the ejectors and presents the mould for cleaning and loading of inserts. 

The essence of the early 1960s process was that one injection unit fed 4, 6, 8, 10 or 12 vertical presses on a rotating mould carrier. Sometimes two injection units were used at different mould stations, one injecting a soft upper compound for a bootee and the other a harder sole compound. Sometimes two different coloured compounds were used. 

For applications requiring two different compounds, such as a double hardness sealing ring or a two colour rubber shoe sole, some machines have two injection units. One injects into the bottom/centre mould plate and the other into the parting line. Two injection units on a singlestation vertical press are used in combination with twin rotating cavity plates. 

This process uses the plasticising and heat advantages of the injection unit to impart good flow properties to the rubber mix. It also offers the advantages of the flexibility of the transfer layout without the sprue and runners of the balanced runner system required by injection moulding. The space used by runners in other systems can be profitably used by more mould cavities. 

After the mould has closed, but before final clamping, a measured quantity of rubber is injected into the transfer port. The rubber forces the transfer port open until it contains the required volume. With a top injection system the mould is forced downwards and the transfer piston remains stationary. With a bottom injection unit the mould is stationary and the transfer piston is raised. In both cases the effective volume of the port is increased by the filling action of the rubber. 

Tables 5.1 and 5.2 display some examples of clamping and injection unit characteristics. There are a large number of machines and these data are only examples without claiming to be exhaustive.

An injection unit doses and mixes the monomer and catalyst. The mix is discharged under pressure, through an injection cone, into the closed mould. The injection pressure is not negligible and the moulds must be rather rigid and resistant. The precision of the cavity and the quality of its surfaces govern the precision and finish of the parts. 

Injection molding involves two distinct processes. The first is melt generation, mixing, and pressurization and flow, which is carried out in the injection unit of the molding machine. The second is product shaping, which takes place in the mold cavity. Injection molders, therefore, have two distinct parts the injection unit and the mold/clamping unit. The function of the injection unit is to melt the polymer and inject it into the mold the function of the clamping unit is to hold the mold, open and close the mold, and eject the finished product. 

To ensure that the anti-foam agent was adequately mixed, it was injected upstream of the dehydrators. Thus, an existing demulsifier injection unit with the necessary feed tank and metering pumps could be used temporarily... 

To safeguard future operations, additional reliability was built into the design of the permanent anti-foam injection unit. This included separate power supply sources ior the running and standby injection pumps with low-flow arid pump-failure alarms in the process control room... 

Fridman ML, Konyshev YuV, Ivankov DV (1971) Injection unit of molding machine. Auth. Certif. USSR No. 291803, Bull. No. 4... 

The plasticating and injection unit. A plasticating and injection unit is shown in Fig. 3.45. The major tasks of the plasticating unit are to melt the polymer, to accumulate the melt in the screw chamber, to inject the melt into the cavity, and to maintain the holding pressure during cooling. 

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