Venturi pump

Decant or aspirate the supernatant. Aspiration, using a Pasteur pipette attached to a simple Venturi pump, is normally preferable unless very wide-base tubes are used. 

Foam inhibitors are always insoluble materials, usually liquids, but some solids such as waxes, gums, or soaps are used. Their foam-inhibiting action arises from their ability to spread spontaneously over the surface of the foamy liquid. A single drop of the spreading liquid, once it has arrived at the surface of the liquid film, acts effectively is a venturi pump, ejecting on every side all the liquid lying... 

Figure 3 Front view of machine. Vie small box on the left side of the bottom shelf is the venturi pump, Vacuum storage tanks are in the background. Notice the frailer tongue jack mounted on the top shelf. It is used to raise and lomr the platen. The coturol panel contains the vacuum gauge on the left, the heater control dial and indicator light in the center and on the right side of the panel is the electric vacuum pump switch and indicator light.

The valve that opens and closes the tine between the venturi pump and the storage tanks is opened and we begin pulling a vacuum on the tanks. 

Your machine will use a dual vacuum source being either an air venturi pump or electric vacuum pump. And your professional quality forming machine will be on wheels making it easy to move when not in use. 

The final result of my endeavors and the subject of this book is the machine shown in figure 1. It uses a 120 volt heating element and is capable of forming 12 x 15 sheets of plastic up to l/4 thick and uses both positive and negative molds. The machine shown in figure 1 is using an air venturi pump for the vacuum source, but the it is set up to easily operate with an electric vacuum pump if you so choose. The machine is built on wheels so it can be easily moved from place to place and anotlier nice feature is the adjustable platen table making it possible to form molds of different sizes. 

The valve mounted on the left front leg of the cart is used to control the incoming air supply to the venturi pump if one is used. The two valves on the top shelf of the cart operate as follows The valve on the left connects the vacuum pump directly to the storage tanks. With the valve open you can pull a vacuum on the tanks. After a vacuum has been pulled you close the valve to store the vacuum. The valve on the right opens and closes the vacuum line from the storage tanks to the platen.To form a sheet of plastic, you would open this valve. 

Air venturi pumps create a vacuum by forcing compressed air through a limiting orifice into a venturi section. As the air exits the orifice it expands, increasing in velocity to supersonic speeds before entering the venturi section. This creates a vacuum or negative pressure at the vacuum inlet port. In the past air venturi pumps have been an expensive device. I had considered making one until I discovered... 

The collection of particles larger than 1—2 p.m in Hquid ejector venturis has been discussed (285). High pressure water induces the flow of gas, but power costs for Hquid pumping can be high because motive efficiency of jet ejectors is usually less than 10%. Improvements (286) to Hquid injectors allow capture of submicrometer particles by using a superheated hot (200°C) water jet at pressures of 6,900—27,600 kPa (1000—4000 psi) which flashes as it issues from the nozzle. For 99% coUection, hot water rate varies from 0.4 kg/1000 m for 1-p.m particles to 0.6 kg/1000 m for 0.3-p.m particles. 

Capacity. Pumps deHver a certain capacity, Q, sometimes referred to as flow, which can be measured directly by venturi, orifice plate (11), or magnetic meters (12) (see Flow measurement). The indirect way to determine capacity is often used. Whereas this method is less accurate than applying a flow meter, it often is the only method available in the field. The total head is measured and the capacity found from the pump head—capacity (H— curve (Fig. 2). More recently, sonic flow meters (13) have been used, which can be installed on the piping without the need for pipe disassembly. These meters are simple to use, but require relatively clean single-phase Hquid for reHable measurements. 

Jet Pumps. A jet pump is a clever way of using a high pressure motive fluid and a venturi to aspire a low pressure fluid to an intermediate pressure level. 

The principal advantage of self-induced spray scrubbers is the efim-ination of a pump for recirculation of the scrubbing liquid. However, the designs for high-energy service are somewhat more complex and less flexible than those for venturi scrubbers. 

FIG. 23-25 Typ es of industrial gas/Hqiiid reactors, (a) Tray tower, (h) Packed, counter current, (c) Packed, parallel current, (d) Falling liquid film, (e) Spray tower, if) Bubble tower, (g) Venturi mixer, h) Static in line mixer, ( ) Tubular flow, (j) Stirred tank, (A,) Centrifugal pump, (/) Two-phase flow in horizontal tubes. 

The power consumed to operate a wet electrostatic precipitator is much less than that required by most other methods of control. There are four areas in which power is consumed (1) electrostatic power, (2) fan power, (3) insulator heating power, and (4) pump power. The total electrostatic power input required for operation is 0.8 to 1.0 kW/1,000 ft of collection area. A comparable piece of equipment is a venturi scrubber with 50-in.wg pressure drop. The power required for this installation would be 6 to 7 kW/1,000 cfm. This would mean that approximately seven times the power would be needed to achieve the same amount of cleaning with a venturi scrubber as opposed to using a precipitator. 

The scrubbing liquid is fed into the pool at the bottom of the scrubber and later recirculated from the entrainment separator baffles by gravity instead of being circulated by a pump as in venturi scrubbers. Many devices using contactor ducts of various shapes are offered commercially. The principal advantage of this scrubber is the elimination of a pump for recirculation of the scrubbing liquid. 

Fig. 3.3 1-3 Cooling Tower Water (. hloriuiiiiuu Basin water u- circulated by the pump throitgi the venturi at 3t> gpm. Chlorine gas, piiivulril ir. a ton tank, is reduced to zero pressure ni tr.e /r.. s snj c reducing valve to be brought in - < llie u. /-...

Air ejectors (jet pumps) A device injecting high-velocity (pressurized) primary air into the secondary air. It allows air to be moved without passing through a fan, it may be a simple or Venturi-type ejector. 

Saug-luft, /. vacuum, suction inlet air. -luft-anlage, /. vacuum equipment or plant, -liifter, m. exhauster, -luftkessel, m. vacuum vessel, -maschine, /. exhauster aspirator, -messer, m. vacuometer. -nkpfchen, n. suction cup. -papier, n. absorbent paper, -pipette, /. suction pipet(te). -pumpe, /. suction pump, -raum, m. suction chamber, -rohr, n., -rohre,/. suction tube or pipe, sucking pip siphon Venturi tube, -rdhrehen,... 

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