Pumps axial piston

Piston pumps are reliable and durable but are usually higher in cost than other pumps. Examples of piston pump types include radial piston pumps, axial piston pumps, swash plate in-line piston pumps, wobble plate in-line piston pumps, and bent axis or angle type pumps. A piston pump and component parts are shown in FIGURE 9-7. 

In 1840 a hydrauHc power network, which involved large reciprocating pumps that were driven by steam engines, suppHed fluid power to London. However, concurrent technology in steam (qv) turbines and the electric generators outmoded such networks until hydrauHc systems were improved with the use of rotary pumps and oil. The rotary piston pump marked the transition from use of water to oil as the hydrauHc fluid (4). The use of vacuum-distilled, refined mineral oils were instmmental in the success of rotary axial piston pumps and motors such as the Waterbury variable speed gear... 

High water-content fluids are used in some hydrauhc systems where work-stroke speeds are very low, eg, large freight elevators and large forging and extmsion presses. Pressures in these systems may be from 13.8—20.7 MPa (2000—3000 psi). Vertical in-line pumps with packed plungers and special axial—piston pumps are used with these fluids. 

Fixed-volume and variable-volume pumps are the two types commonly applied in the press application. Fixed-volume pumps are normally vane type and are used for fixed-speed presses and for auxiliary circuits such as filtering, cooling, and pilot pressure. Variable-volume pumps are normally radial or axial piston type and are used for variable pressing speeds and pressure compensated circuits. 

The two variable-delivery axial piston pumps k and I for the motions of the ram and the piercing mandrel are driven by a common motor and arranged on the top of the frame directly above the main cylinder. The oil collector tank and two geared pumps for the auxiliary drives are arranged in a pit below floor level. The auxiliary drive units operate the container and die-carrier shifting devices, the shear, the locking mechanism of the die-carrier and the control gears of the two axial piston pumps. 

We selected our standard fixed stroke 906 size aircraft piston pump for pumping liquid nitrogen. This unit consists of 9 axial pistons 3/l6 in. in diameter), a cylinder block, a valve plate, a drive shaft supported by anti-friction roller bearings, and an aluminum housing. The pump has a theoretical hydraulic displacement of 0.095 cu, in. per revolution and a rated continuous speed of about 7, 000 RPM, with an intermittent speed rating of 12,000 RPM. 

Mixed flow pumps Incorporate the features of both axial flow pumps and radial flow pumps. Axial flow pumps operate on a vertical plane and radial flow pumps operate on a horizontal plane to the flow direction of water. Mud pumps Built to transfer heavy sludge or mud. Some larger versions are used to pressure. Th are sometimes used on oil rigs to pressurize and circulate fluid. Petrochemical pumps Made to transfer petroleum products that are often very viscous and corrosive. They can be magnetic drive pumps, diaphragm pumps, piston pumps, and others. 

In much the same manner as pumps, compressors are classified as one of two general classes positive displacement or dynamic (see Figure 3-68) [23]. These two general classes of compressors are the same as that for pumps. The positive displacement class of compressors is an intermittent flow device, which is usually a reciprocating piston compressor or a rotary compressor (e.g., sliding vane, screws, etc.). The dynamic class of compressor is a continuous flow device, which is usually an axial-flow or centrifugal compressor (or mix of the two). 

Non-contact seals with defined narrow clearances, such as labyrinth seals in turbo-machines (Fig. 4.1-47 A), are less problematic owing to the relatively low differential pressures however, the fluid should not have an erosive effect. Differential pressures up to several hundred bar occur at the axial-thrust compensation pistons of centrifugal pumps and compressors, but the fluid expansion is distributed over the many labyrinth stages. 

The metering system takes the conditioned intermediates from the supply tanks and delivers them to the mixing head at the desired rate and pressure. There are two basic types of metering systems high pressure axial or radial piston pumps, and lance displacement cylinders. The piston pumps are hydraulic pumps that have been modified to handle chemicals. They are capable of continuously metering at... 

Analytical columns are packed by the slurry technique, where a dilute suspension of the packing is pumped at a high flow rate and a high pressure through the column. Particles are retained by a porous frit at the end of the column. Preparative columns with dp between 10 and 30 xm are, preferably, packed by the dynamically axial compression technique (Unger, 1994). The column contains a movable piston that keeps the packing under an external pressure during operation. The operation pressure should be always less than the piston pressure. 

Several types of compressor have characteristics intermediate between those of PD compressors and centrifugal or axial-flow compressors. These include the lobe type, sliding vane, and liquid piston. For all these, the discussion of compressor work and compressor efficiency applies just as well as the above-mentioned types. Descriptions of the mechanical arrangements of these can be found in texts on pumps and compressors [2]. 

A variable-delivery axial pump is shown in Fig. 174. The drive shaft a is seated in the pump housing in two bearings and has seven cylinder bores, arranged parallel to its axis, with pistons h. The pistons sit with spherical shoes c on a thrust bearing in the cradle d. At each rotation of... 

In axial pumps the reversal of the fluid flow direetion may eause significant down times when several reversals are used. In a novel system discussed by Cegarra, a piston-like device inside the kier is used that allows frequent and efficient flow reversals. 

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