Pumps hydraulic pressure

K — Hydraulic pressure pump L — Pressure surge chamber (not recommended)... 

Oil-hydraulic pressure pumps are frequently employed for the operation of cable presses instead of pressure water pumps, see p. 203. Their advantage being that they require less floor space and that they may even be mounted on the press. Claims in favor of pressure water pumps are the higher operating pressures, resulting in a simpler design of the press, and, last not least, the elimination of the danger of fire. 

Fig. 167, 168 and 169 show an oil-hydraulic pressure pump the outstanding feature of which being the provision of intake- and delivery valves. This pump has proved itself especially at high pressures of 300 to 400 atmospheres on a continuous duty basis. Valve-less pumps have... 

Variable delivery oil-hydraulic pressure pumps are in axial or radial design as illustrated in the schematic representation Fig. 170. The radial pump possesses a stationary shaft a on which the pump body 6, which is. 

The principle of operation of the hydraulic reciprocating pump is similar to the beam pump, with a piston-like sub-surface pump action. The energy to drive the pump, however, is delivered through a hydraulic medium, the power fluid, commonly oil or water. The power fluid drives a downhole hydraulic motor which in turn drives the pump. A separate surface pump delivers the hydraulic power. The power fluid system can be of the closed loop or of the open type. In the latter case, the power fluids are mixed with the produced fluid stream. The performance of the hydraulic pump is primarily monitored by measuring the discharge pressures of both surface and sub-surface pumps. 

The jet pump relies on the same hydraulic power being delivered sub-surface as to the hydraulic reciprocating pump, but there the similarity ends. The high-pressure power fluid is accelerated through a nozzle, after whioh it is mixed with the well stream. The velocity of the well stream is thereby increased and this acquired kinetic energy is converted to pressure in an expander. The pressure is then sufficient to deliver the fluids to surface. The jet pump has no moving parts and can be made very compact. 

The characteristics of the pump relate the applied pressure on the cake to the flowrate at the exit face of the filter medium. The cake resistance determines the pressure drop. During filtration, liquid flows through the porous filter cake in the direction of decreasing hydraulic pressure gradient. The porosity (e) is at a minimum at the point of contact between the cake and filter plate (i.e., where x = 0) and at a maximum at the cake surface (x = L) where sludge enters. A schematic definition of this system is illustrated in Figure 2. 

Underreamer Hydraulics. Pressure losses across the underreamer nozzles (orifice) are shown in Figures 4-178 and 4-179 [58]. The shaded area represents the recommended pressure drop required for cutters to fully open. These pressure drop graphs can be used for pressure losses calculations (given pump output and nozzles) or for orifice (nozzle) selection (given pump output and pressure loss required). 

This is the energy source for hydraulic systems. It converts electrical energy into dynamic, hydraulic pressure. In almost all cases, hydraulic systems utilize positive displacement pumps as their primary power source. These are broken down into two primary sub-classifications constant-volume or variable-volume. In the former, the pumps are designed to deliver a fixed output (i.e. both volume and pressure) of hydraulic fluid. In the later, the pump delivers only the volume or pressure required for specific functions of the system or its components. 

Over the years the performance standards of hydraulic equipment have risen. Whereas a pressure of about 1000 psi used to be adequate for industrial hydraulic systems, nowadays systems operating with pressures of 2000-3500psi are common. Pressures above 5000psi are to be found in applications such as large presses for which suitable high-pressure pumps have been developed. Additionally, systems have to provide increased power densities, more accurate response, better reliability and increased safety. Their use in numerically controlled machine tools and other advanced control systems creates the need for enhanced filtration. Full flow filters as fine as 1-10 micron retention capabilities are now to be found in many hydraulic systems. 

The conjoint action of a tensile stress and a specific corrodent on a material results in stress corrosion cracking (SCC) if the conditions are sufficiently severe. The tensile stress can be the residual stress in a fabricated structure, the hoop stress in a pipe containing fluid at pressures above ambient or in a vessel by virtue of the internal hydraulic pressure created by the weight of its contents. Stresses result from thermal expansion effects, the torsional stresses on a pump or agitator shaft and many more causes. 

In the recycle flow pressurization system (Figure 27.10), a portion (15-50%) of the clarified effluent from the flotation chamber is recycled, pressurized, and semisaturated with air in the air dissolving tube. The recycled flow is mixed with the unpressurized main influent stream just before admission to the flotation chamber, with the result that the air bubbles come out of aqueous phase in contact with suspended particulate matter at the inlet compartment of the flotation chamber. The system is usually employed in applications where preliminary chemical addition and flocculation are necessary and ahead of flotation. It eliminates the problems with shearing the flocculated particles since only the clarified effluent passes through the pressurizing pump and the friction valve. It should be noted, however, that the increased hydraulic flow on the flotation chamber due to the flow recirculation must be taken into account in the flotation chamber design. 

Air from a cylinder at pressures up to about 10 bar (150 psi) is applied to a gas piston that has a relatively large surface area. The gas piston is attached to a hydraulic piston that has a smaller surface area. The pressure applied to the liquid = gas pressure x area of gas piston/area of hydraulic piston. With 10 bar inlet pressure and a 50 1 area ratio, the hydraulic pressure obtained is 500 bar (7500 psi). On the drive stroke, the outlet valve on the pump head is open to the column and the inlet valve closed to the mobile phase reservoir. At the end of the drive stroke, the air in the chamber is vented and air enters on the other side of the gas piston to start the return stroke. On the return stroke the outlet valve closes, the inlet valve opens and the pump head refills with mobile phase. The pump can be started and stopped by operation of a valve fitted between the cylinder regulator and the pump. 

Hydraulic fracturing is a method of stimulating production of oil or gas from rock formations. A fluid is pumped under conditions of high pressure and high rate Into the formation to fracture it. The fluid also carries sand or a similar proppant material into the fractures. When the pumping is stopped and the hydraulic pressure is released at the wellhead, the fracture partially closes on the sand leaving a highly permeable channel for the oil or gas to flow back to the well. 

The direction and flow rate of the test and hydraulic fluids are determined by nine three-way valves and six a1r-dr1ven hydraulic pumps that must be sequenced 1n the proper order. The position of the valves 1s determined by six air-driven actuators. Two of the pumps are miniaturized, air-driven, hydraulic pumps used for sample loading and pressurization. One of the remaining four pumps 1s a high-pressure, constant volume, positive displacement, piston metering pump to provide hydraulic pressure, and the other three are positive displacement syringe pumps for In-line addition of additives. 

A hydraulic press is powered by a remote high pressure pump. The gage pressure at the pump is 20 MPa, and the pressure required to operate the press is 19 MPa (gage) at a flow rate of 0.032 m3/min. The press and pump are to be connected by 50 m of drawn stainless steel tubing. The fluid properties are those of SAE 10 lube oil at 40°C. What is the minimum tubing diameter that can be used ... 

Fig. 16.12 Principle and advantages of the falling film electrolyser. Advantages include improved mass and heat transfer low gas content in electrolyte low concentration difference constant hydraulic pressure low expected voltage of 2.70 V at 3 kA m-2 leading to power consumption reduction of 70 kWh per tonne of NaOH at 4kA m-2, including circulation pumps and small element depth. 

Z) Walking Bearn Test. The purpose of this fuze test is to det the operating characteristics of pressure-actuated fuzes. The test consists of placing the test fuze under the end of a rod that is attached to the test equipment. A hydraulic hand pump, which is a part of the equipment is operated behind a barticade with the desired load being applied to the fuze (p IIB-40 of Ref 39)... 

The EOF-induced flow has been amplified by using multiple capillary channels (of width 1-6 pm), so that the multiple flow streams are combined to produce adequate hydraulic pressure for liquid pumping (see Figure 3.7) [115]. The multiple channels (100) ensure the generation of sufficient flow rate (10-400 nL/min), while the small dimensions (of depth 1-6 pm) result in the necessary hydraulic pressure to prevent pressurized backflow leakage (up to 80 psi) [115]. Based on a similar approach, a narrow-gap EOF pump was constmcted to produce 400 Pa pressure with 850-nm-deep channels cascaded in three stages to produce a 200-pm/s flow velocity [390]. Another pump was constructed with 130-nm-thin channels cascaded in 10 stages to produce 25 kPa pressure [264]. 

Answer 11.6 The Migennes well has already been discussed in the text. It is reported to be a confined well, but the tritium-14C combination indicates two water types are pumped in this well as a mixture. This nature is distinct from the comparison of the repeated measurements (10/67 and 7/69). In the last sample the percentage of recent water was greater than in the first sample. Corrosion and rupturing of the well casing may have deteriorated the well, so it pumps an increasing amount of shallow recent water. However, such a well may cause a short circuit between the two aquifers due to different hydraulic pressures, water from one aquifer may flow uncontrolled into the other aquifer. Repair of the well may be necessary. 

Typical "plant equipment is shown in Fig. 3. The equipment racks are assembled and tested before being installed in hot cells. This rack, which served for some five years, has one high-pressure pump, a short "loading column, two long elution columns, and appropriate associated valves, feed vessels, product collection apparatus, and plumbing. Resin was periodically replaced by hydraulic transfer. 

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