Pump cavitation occurs and the stage and type

First, the process of cavitation occurs when the pressure of liquid vaporization of liquid vaporization pressure (saturated vapor pressure). The size of liquid vaporization pressure and temperature. The higher the temperature, the more intense the molecular motion, the greater the pressure of vaporization. The vaporization pressure of 20 Â° C clear water at normal temperature is 233.8 Pa (0.0238 kgf / cm2), while the vaporization pressure of 100 Â° C water is 10,1296 Pa (1.033 kgf / cm2) (a large steam pressure). Therefore, at room temperature (20 â„ƒ) â€‹â€‹water pressure drops to 233.8Pa, began to vaporization. Visible, under certain temperature pressure is to promote liquid vaporization of the external factors. Liquid at a certain temperature, reducing the pressure to the temperature of the vaporization pressure, the liquid will produce bubbles. The phenomenon of bubbles is called cavitation. However, the gas inside the bubble is actually not exactly steam but also contains gas (mainly air) in the form of a solution or a core. The dissolved gas in the liquid diffuses into the bubble and encourages the growth of bubbles. Cavitation bubble generated when flowing to high pressure Department, its volume decreases and even burst. This phenomenon of air bubbles disappearing into the liquid due to the pressure increase is called cavitation collapse. Second, the stage and types of cavitation The occurrence of cavitation can be divided into the following stages 1. The nascent stage: with the naked eye or other means to detect the occurrence of cavitation 2. Advanced stage: further development of the nascent stage, a fierce occurred Stage 3. Final stage: stage of disappearance of bubbles due to pressure rise Cavitation is divided into the following four types: 1. Free or moving cavitation 2. Fixed or attached cavitation 3. Vortex cavitation 4. Vibrating cavitation Free cavitation is performed at Flow of liquid bubbles, while growing in the liquid to high pressure and collapse. Fixed cavitation is placed in the flow of objects on the surface or the side walls to form holes, and attached to the wall above. Vortex cavitation occurs in the vortex in the low pressure part of the hole, the propeller wing end of the cavitation belongs to this cavitation. Vibrating cavitation is a kind of cavitation occurring in large-amplitude and high-frequency pressure pulsating liquids. Cavitation erosion experiments often use this kind of cavitation, which is usually not seen in hydraulic machinery and often occurs in hydraulic machinery at the same time Cavitation and fixed cavitation.

Hejian Deris Both manufacturer and distributor, specialize on Hole opener ranging from 8inch to 66inch that is divided into three types: MT Hole Opener and TCI Roller Cones Hole Opener, PDC Hole Opener, Assembly drill bit are used in various compressive strength of the formations. The product widely used for the reaming of the water , oil, gas, petrochemical, sewage, power and fiber optic pipelines in the no-dig horizontal directional drilling.

Feature of Roller cones hole opener

Hole opener Size	8",10",12",14",16",18",19",20",22",24",26",28",30",32", 36",40",42",44",46",48",52",58",60",66"
Cones type	117, 127, 217, 317, 417,437,517, 537, 617, 637
Cones Bearing	Rubber or metal sealed journal bearing
Connection	3 1/2";4 1/2";6 5/8";7 5/8"API reg pin /box
Nozzle Qty	5NZ (according to your demands)
Make up Torque(KN.m)	4 -4.8 / 6-7.5 / 9.5-12 / 16-22 / 38-43 / 46-54
Formation	soft ,medium soft ,hard,medium hard,very hard formation

PDC hole opener feature

Hole opener Size

8",10",12",14",16",18",19",20",22",24",26",28",30",32",

36",40",42",44",46",48",52",58",60",66"

Blades
3 blades 4 blades 5 blades 6 blades ,7 blades 8 blades 9 blades or as your need

Body type

Matrix and steel body

Connection

3 1/2";4 1/2";6 5/8";7 5/8"API reg pin / box

Cutter size 1308 1313 1613 1616 1916

Nozzle Qty

5NZ (according to your demands)

Make up Torque(KN.m)

4 -4.8 / 6-7.5 / 9.5-12 / 16-22 / 38-43 / 46-54

Formation

soft ,medium soft ,hard,medium hard,very hard formation

The Hole Opener Advantage

Straighter Holes- By drilling a smaller hole with a "pilot" bit, then attaching that said bit onto the bottom of the hole opener. The hole opener will follow the path of the hole drilled by the smaller bit.

Larger Holes with Smaller Rigs - By drilling a hole in stages, larger holes can be drilled with smaller rigs. A smaller hole requires less power.

Replacing Cutters and Cutting Cost- On most Hole Opener designs, the cutters can be easily replaced. The cost to replace a cutter is a fraction of the cost to replace a large Tricone Rock Bit.

Cost of Large Rock Bits - Larger diameter rock bits not only cost a lot, they can be difficult to find. A more economic solution is to use a hole opener that uses smaller tricone rock bit segments..

Flexibility - Hole Openers can be fabricated in just about any size, and can be configured to drill through any formation.

Operational Considerations

Drilling Weight - The choice of drilling weight is determined based on the recommendations of the bit manufacturer and the number of cutters on the hole opener.

Number of Cutters - The number of cutters placed on a hole opener is governed by the following facts:

1.Maximum number which will fit around the perimeter.

2.The greater the number of cutters, the less the weight, which therefore reduces the penetration rate.

3.In softer formations, less weight is needed to penetrate.

4.The greater the number of cutters, the smoother the tool will run.

5.The greater the number of cutters, the greater the cost.

6.The greater the number of cutters, the longer the cutters will last

Rotary Speed - Maximum speed is determined by the manufacturer's recommendation and the calculation to account for the linear distance the cutter is moving per revolution.

Hole Cleaning - A frequently over looked point of hole opener operation is hole cleaning. The volume of cuttings to remove from a hole increase by a squared factor with an increase in hole diameter.

Hole Opener

Hole Opener,Diamond Hole Opener,Trenchless Hole Opener,Non-Dig Hole Opener

Hejian Deris Petroleum Drilling Equipment Co.,Ltd. , http://www.welldrillingbit.com