Answer EKG Question 26

Q26. With reference to Gear pumps used for lubricating oil transfer. (a) Sketch and describe a gear type pump indicating the flow of fluid. (b) state the materials that gear type pump components may be manufactured from. (c) specify THREE applications that are suitable for the employment of gear type pumps.

Answer:

(a) Sketch and describe a gear type pump indicating the flow of fluid.

 pump uses two identical gears rotating against each other --one gear is driven by a motor and it in turn drives the other gear.Each gear is supported bya shaft with bearings on both sides of the gear. 

1.As the gears come out of mesh, they create expanding volume on the inlet side of the pump. Liquid flows into the cavity and is trapped by the gear teeth as they rotate.

2.Liquid travels around the interior of the casing in the pockets between the teeth and the casing --it does not pass between the gears. 

3.Finally, the meshing of the gears forces liquid through the outlet port under pressure

1 Gland / Seal Housing	6 Rotors (2)	11 Bushes – Back Cover	16 Locknut
2 Shaft Sealing	7 Key	12 Back cover	17 Adjusting Screw
3 Front cover	8 Body Gaskets	13 Relief Valve	18 Plug
4 Bushes – Front Cover	9 Following Shaft	14 Spring
5 Driving shaft	10 Body	15 Sealing Washer

(b) state the materials that gear type pump components may be manufactured from.

Externals (head, casing, bracket)-Iron, ductile iron, steel, stainless steel, high alloys, composites (PPS, ETFE)

Internals (shafts)-Steel, stainless steel, high alloys, alumina ceramic

Internals (gears)-Steel, stainless steel, PTFE, composite (PPS)

Bushing-Carbon, bronze, silicon carbide, needle bearings

Shaft Seal-rubber oil seal, Gland Packing, lip seal,mechanical seal.

(c) specify THREE applications that are suitable for the employment of gear type pumps.

(1)The gear pumps are used widely for engine lubrication.

(2) For transfer of lub oil and fuel oil in ships.

(3) For hydraulic power transmission in deck machinery