CIG Pump with Different Teeth

CIG Pump with Different Teeth

Inventor: Varuzhan Harutyunyan, Nor-Nork 9th massive 97/7, 0059 Yerevan, Armenia

Application No.: AM20120061U

Filed: April 16, 2012

Field of the invention

The invention concerns positive displacement rotary pumps and compressors. 

Description of related art

A crescent internal gear pump in the field concerned is described in the book: A. G. Skhirtladze, V. I. Ivanov, V. N. Kareev “Gidravlicheskie i pnevmaticheskie sistemi” pages 94-101, published at 2006.

Abstract

The utility model represents as positive displacement rotary pump.

CIG Pump with Different Teeth consists of a case with two ports: one for the liquid suction and the other one for the liquid discharge, internally meshing cylindrical external gear connected with actuator, internal gear and crescent part rigidly mounted with the case.

The external gear additionally has two opposite big teeth having the pitch greater than pitch of small teeth in 3, 5, 7 or more times, while the internal gear has three big cavities apart from each other at an angle 1200 and having the pitch greater than pitch of small teeth in 3, 5, 7 or more times.

Because of the high volume of the chamber between two opposite big teeth of external gear, the pump has high admission and compression ratio, which improves the pump performance characteristics and enables to use it as compressor as well.

The reliability and effectiveness are enhanced.

Brief Description of the Drawings

Fig. 1 is an axonometric view of the CIG Pump with Different Teeth without cover

Fig. 2 is a plan view of the pump without cover

Description

Engineering level

The crescent internal gear pump consists of meshing internal and external cylindrical gears, case and a crescent part rigidly mounted with the case, which has two ports: one for liquid intake and the other one for its discharge. One of the gears receives rolling motion from actuator, while the other one rotates through meshing with the previous gear. The liquid is filled into the cavities between teeth and is delivered to discharge port along the crescent part contours. The liquid cannot flow in the opposite direction because of the teeth internal meshing.

The pump has following limitations:

Since the suction occurs when a tooth of one gear leaves a cavity of the other gear, the pump generates low vacuum, which prevents its use for delivering high viscous liquids and limits suction head as well. Based on the suction and discharge nature, the pump has low admission and compression ratio, which results high volumetric losses after slight wear of teeth especially at high pressure. Because of the low compression ratio, the device cannot be used as compressor.        

Disclosure of the utility model

The purpose of the invention is to improve the gear pump design so, that it will have relatively high admission and compression ratio to enhance its volumetric efficiency and to enable its usage as compressor. The pump has external gear 1 and internal gear 2. The external gear is in pin connection with case 3 through shafts 4, whereas the internal gear is inserted in the case. Between the gears there is a crescent part 5, which divides the volume flanked by them into two chambers. The case has inlet 6 and outlet 7 ports. The external gear 1 has many small teeth 8 and two opposite big teeth 9, whereas the internal gear 2 has many small teeth 10 and three big cavities 11. The pitch of the big teeth and the big cavities is greater than the pitch of small teeth in 3, 5, 7 or more times. The contours of all teeth of the external gear have the same pitch diameter 12, whereas the contours of small teeth and big cavities of the internal gear have the same pitch diameter 13. The gears are mounted against each other in the case in such a way that a big tooth of the external gear meshes with a big cavity of the internal gear. The pump operates in the following way: The actuator 14 rotates the external gear 1 through shaft 4. The internal gear 2 is rotated from the external gear 1 through meshing. When the pump rotates in the mentioned direction of Fig. 2, the liquid is filled through inlet port 6 into continuously increasing chamber between a big tooth and the internal gear teeth till another big tooth gets in touch with crescent part flank. Afterwards the liquid travels in the chamber between two big teeth in constant quantity till the next big tooth gets free of touch from crescent part flank. Then the liquid is discharged through the outlet port 7, because the volume of the liquid bounding chamber continuously decreases. The liquid is delivered through the cavities of the internal gear too. The gear meshing eliminates the liquid opposite flow from discharge zone to suction zone. Because of the high volume of the chamber between two opposite big teeth of the external gear, the pump has high admission and compression ratio, which reduces volumetric losses, provides high suction head, enables to deliver high viscous liquids and to use it as compressor. Since the gears have a lot of small teeth (rated), more teeth are engaged in meshing, which improves meshing hermeticity and volumetric efficiency accordingly. The pump can be used in hydraulic machines as pump and hydraulic motor and can deliver lubricants, liquid fuel and other liquids as well. The pump can be used as compressor to compress gases like refrigerants in refrigerating systems, air, various gases in chemical industry etc. It can be used as pneumatic motor too.

Claim

CIG Pump with Different Teeth consists of a case with two ports: one for the liquid suction and the other one for the liquid discharge, internally meshing cylindrical external gear connected with actuator, internal gear and crescent part rigidly mounted with the case.

In addition, the external gear has two opposite big teeth having the pitch greater than pitch of small teeth in 3, 5, 7 or more times, while the internal gear has three big cavities apart from each other at an angle 1200 and having the pitch greater than pitch of small teeth in 3, 5, 7 or more times.