CN1141561C - Device and method for testing output performance of impacter - Google Patents

Abstract

The present invention relates to a method and a device for testing the output performance of an impact device by the air pressure change of a sealed air chamber. The present invention is characterized in that the tail part of a piston 2 of the impact device 1 is provided with the sealed air chamber 3, and an outer shell of the sealed air chamber and a cylinder body of the impact device are correspondingly fixed; the output performance of the impact device is tested by testing the air pressure change in the air chamber 3 due to the movement of the piston 2 in the sealed air chamber 3 in definite time. Tested data is accurate, rapid and convenient.

Description

The proving installation of output performance of impacter and method of testing

The present invention relates to a kind of method of testing and equipment thereof that utilizes gas pressure change in the seal air cavity to detect output performance of impacter.

Knocker impact property parameter is to weigh an importance of knocker level and quality, and its major parameter needs to measure by research technique, and goes out the result with data or diagrammatic representation.Impact energy and frequency of impact are mainly measured in the examination of knocker performance.Knocker impact property method of testing commonly used at present has stress wave, the photoelectric displacement differential method, inductive electromagnetic method, contact method, high-speed photography method, load-position diagram method and energy method.Yet, because the restriction of tested person instrument and equipment, these methods exist that the preliminary work amount is big, complicated operation, high material consumption, expensive and to defectives such as the reflection of piston motion state are incomplete, especially are not suitable for the running of impact device at the construction field (site) and do to detect in good time.

The objective of the invention is to find a kind of accurately, safety, economy, quick and easy knocker performance test method and device thereof.

The present invention is that the technical scheme that adopts that achieves the above object is:

1. a cover output performance of impacter proving installation is provided, it is made up of knocker 1, piston 2, seal air cavity 3, packoff 4, pressure transducer 5, data acquisition board 6, computer system 7, display system 8 (printer, display), it is characterized in that: piston 2 afterbodys of knocker 1 are installed the cylinder body relative fixed of an airtight air cavity 3 and knocker 1, one end of its inside forms an airtight air cavity 3 by O-ring seal 4 shutoff, and the other end connects pressure transducer 5.

2. a kind of method---pneumatic process of the impact device 1 output performance test of adopting said apparatus and realizing is proposed.By regularly detecting, and obtain the parameter of knocker output services performances such as corresponding piston 2 speed, displacement, impact energy, frequency of impact through computer system calculating with this because of piston 2 variation of gas pressure in the air cavity 3 that causes of in seal air cavity 3, move.

The proving installation and the data that method of testing is surveyed of output performance of impacter of the present invention are accurate, handling safety, quick and easy.Not only be used in the laboratory a certain product is made performance test, also can realize the online detection of knocker performance easily.Help the adaptability and the security of construction operation greatly, help operation and managerial personnel and grasp equipment running status in good time, and help the maintenance of equipment.

Be further described below in conjunction with accompanying drawing:

Fig. 1: be the formation synoptic diagram of proving installation of the present invention;

Fig. 2: be the graph of relation between adiabatic process gaseous tension P of the present invention and the volume V;

Fig. 3: be principle of work synoptic diagram of the present invention.

Fig. 1 has described the composition of proving installation of the present invention.Piston 2 afterbodys of knocker 1 are installed the cylinder body relative fixed of an air cavity 3 and knocker 1, one end of its inside forms an airtight air cavity 3 by O-ring seal 4 shutoff, and the other end connects pressure transducer 5 and forms with data acquisition board 6, computer system 7, display 8, printer 9.

The providing of the above-mentioned test macro of the present invention realized the test with " pneumatic process " impact device output performance.

The gas external world that Fig. 2 has described certain mass does not have under the condition of exchange heat, from a certain state (P ₁, V ₁, T ₁) change to another state (P ₂, V ₂, T ₂) the adiabatic process of change in relation between gaseous tension P and the volume V, this P-V curved line relation meets adiabatic equation:

PV ^kIn=C (1) formula: k-is an adiabatic exponent; C-is a constant.

Fig. 3 has described the test job situation of using output performance of impacter proving installation of the present invention to be carried out.The compression air cavity increases air pressure during piston 2 backhauls, and air cavity 3 pressure reduce during stroke.Piston 2 is in airtight air cavity 3 high speed to-and-fro movements, and the heat in the nitrogen has little time to carry out heat interchange (heat radiation or heat absorption) with the external world, and this process can be regarded as adiabatic process.

At t=t ₁Moment useful area is that the piston of A is in x=x ₁The position, nitrogen pressure is P in this moment nitrogen chamber 3 ₁, volume is V ₁At x=x ₂The position, nitrogen pressure is P in this moment nitrogen chamber 3 ₂, volume is V ₂By adiabatic equation as can be known: $P_1{V}_1^k=P_2{V}_2^k=P_2{[V_4-(x_1-x_2)A]}^k=P_2{(V_1-\mathrm{\Δx}\·A)}^k$ Can get by following formula: $\mathrm{\Δx}=\frac{V_1}{A}\·[1-\sqrt[k]{\frac{P_1}{P_2}}]----\left(2\right)$

Because piston 2 is at Δ t=t ₂-t ₁The time intrinsic displacement is Δ x, passes through x at piston 2 as can be known ₁, x ₂Dot spacing from average velocity be: $\stackrel{\‾}{v}=\frac{\mathrm{\Δx}}{\mathrm{\Δt}}=\frac{V_1}{A\·\mathrm{\Δt}}\·[1-\sqrt[k]{\frac{P_1}{P_2}}]----\left(3\right)$

Following formula P ₁, P ₂Can obtain by 5 pairs of nitrogen chambeies of pressure transducer, 3 pressure timing samplings.When sampling interval hour, then this average velocity can comparatively accurately reflect the piston motion state of 2 this moments.

After obtaining the movement velocity of piston 2, by the stroke maximal rate can be regarded as the impact energy of piston 2.And frequency of impact can obtain by the following method: a series of pistons 2 movement velocity numerical value that obtain after calculating are compared, find two residing times of adjacent velocity peak values, the absolute value of its difference is 2 cycles of piston, and frequency of impact is the inverse in cycle.Its mathematical notation is as follows:

T＝|t _vmax1-t _vmax2| (4)

f＝1/T (5)

If 2 speed cycle of piston variation tendency or 3 air pressure cycle of the nitrogen chamber variation tendency formal representation with curve is come out, then can read 2 periods of motion of piston intuitively, and calculate frequency.

Impact energy and frequency of impact obtain under same test condition in the pneumatic process.

The parameter of knocker output services performances such as the piston speed that the present invention tested, displacement, impact energy, frequency of impact all as calculated the machine system print show, the data of surveying accurate, quick and easy.

Claims (3)

1. output performance of impacter proving installation, it is made up of knocker (1), piston (2), closed cylinder (3), packoff (4), pressure transducer (5), data acquisition board (6), computer system (7), display system (8) (printer, display), it is characterized in that: piston (2) afterbody of knocker (1) is installed the cylinder body relative fixed of an air cavity (3) and knocker (1), one end of its inside forms an airtight air cavity (3) by O-ring seal (4) shutoff, and the other end connects pressure transducer (5).

2. output performance of impacter proving installation according to claim 1, utilize the middle gas pressure change of seal air cavity (3) to detect the method for testing of output performance of impacter, it is characterized in that: detect the middle variation of gas pressure of air cavity (3) of in seal air cavity (3), moving and causing by timing, and obtain the parameter of knocker output services performances such as corresponding piston (2) speed, displacement, impact energy, frequency of impact through computer system calculating with this because of piston (2).

3. method of testing according to claim 2 is characterized in that: the gas external world in the air cavity (3) does not have under the condition of exchange heat, from a certain state (P ₁, V ₁, T ₁) change to another state (P ₂, V ₂, T ₂) the adiabatic process of change in relation between gaseous tension P and the volume V, meet adiabatic equation:

PV ^kIn=C (1) formula: k-is an adiabatic exponent; C-is a constant.

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